NADH pyrophosphatase; NADH pyrophosphatase, also known as NUDIX (nucleoside diphosphate linked moiety X)) motif 13/Nudt13, is thought to have NADH pyrophosphatase activity, be involved in NADH metabolic process and NADP catabolic process, catalyzing the cleavage of NADH into reduced nicotinamide mononucleotide (NMNH) and AMP, and located in mitochondrion. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity. Members of this family are also recognized by the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. A block of 8 conserved amino acids downstream of the NUDIX motif is thought to give NADH pyrophosphatase its specificity for NADH. NADH pyrophosphatase forms a dimer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   2 APVAITLVSDGT-RCLLARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSgSLMIACH 80
Cdd:cd03429    1 DPAVIVLVTNGEdKILLARQPRWPPGRYSLLAGFVEPGETLEEAVRREVKEEVGLRVKNVRYVGSQPWPFPS-SLMLGFT 79

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 545688245  81 ATVKPGqtEIQVNLRELETAAWFSHDEVATALkrkgpytqqqngtfpfWLPPKLAISHQLIKEWV 145
Cdd:cd03429   80 AEADSG--EITVDDDELEDARWFSRDELPEAL----------------FLPPPGSIARRLIRAWL 126

NUDIX domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245    4 VAITLVSDGTRCLLARQSSFP-KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMIACH-- 80
Cdd:pfam00293   6 VGVVLLNEKGRVLLVRRSKKPfPGWWSLPGGKVEPGETPEEAARRELEEETGLEPELLELLGSLHYLAPFDGRFPDEHei 85

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 545688245   81 ---ATVKPGQTEIQVNLRELETAAWFSHDEVATALKRKGPY 118
Cdd:pfam00293  86 lyvFLAEVEGELEPDPDGEVEEVRWVPLEELLLLKLAPGDR 126

NADH pyrophosphatase; NADH pyrophosphatase, also known as NUDIX (nucleoside diphosphate linked moiety X)) motif 13/Nudt13, is thought to have NADH pyrophosphatase activity, be involved in NADH metabolic process and NADP catabolic process, catalyzing the cleavage of NADH into reduced nicotinamide mononucleotide (NMNH) and AMP, and located in mitochondrion. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity. Members of this family are also recognized by the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. A block of 8 conserved amino acids downstream of the NUDIX motif is thought to give NADH pyrophosphatase its specificity for NADH. NADH pyrophosphatase forms a dimer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   2 APVAITLVSDGT-RCLLARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSgSLMIACH 80
Cdd:cd03429    1 DPAVIVLVTNGEdKILLARQPRWPPGRYSLLAGFVEPGETLEEAVRREVKEEVGLRVKNVRYVGSQPWPFPS-SLMLGFT 79

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 545688245  81 ATVKPGqtEIQVNLRELETAAWFSHDEVATALkrkgpytqqqngtfpfWLPPKLAISHQLIKEWV 145
Cdd:cd03429   80 AEADSG--EITVDDDELEDARWFSRDELPEAL----------------FLPPPGSIARRLIRAWL 126

NUDIX domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245    4 VAITLVSDGTRCLLARQSSFP-KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMIACH-- 80
Cdd:pfam00293   6 VGVVLLNEKGRVLLVRRSKKPfPGWWSLPGGKVEPGETPEEAARRELEEETGLEPELLELLGSLHYLAPFDGRFPDEHei 85

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 545688245   81 ---ATVKPGQTEIQVNLRELETAAWFSHDEVATALKRKGPY 118
Cdd:pfam00293  86 lyvFLAEVEGELEPDPDGEVEEVRWVPLEELLLLKLAPGDR 126

NUDIX hydrolase superfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   4 VAITLVSDGTRCLLARQSSFP-KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGS---LMIAC 79
Cdd:cd02883    3 VGAVVFDDEGRVLLVRRSDGPgPGGWELPGGGVEPGETPEEAAVREVREETGLDVEVLRLLGVYEFPDPDEGrhvVVLVF 82

                         90       100
                 ....*....|....*....|....*
gi 545688245  80 HATVKPGQTEIQVNlRELETAAWFS 104
Cdd:cd02883   83 LARVVGGEPPPLDD-EEISEVRWVP 106

8-oxo-dGTP pyrophosphatase MutT and related house-cleaning NTP pyrophosphohydrolases, NUDIX family [Defense mechanisms];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   4 VAITLVSDGTRCLLARQSSFP--KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMI--AC 79
Cdd:COG0494   16 VVVVLLDDDGRVLLVRRYRYGvgPGLWEFPGGKIEPGESPEEAALRELREETGLTAEDLELLGELPSPGYTDEKVHvfLA 95

                         90       100       110
                 ....*....|....*....|....*....|....*
gi 545688245  80 HATVKPGQTEIQVNlRELETAAWFSHDEVATALKR 114
Cdd:COG0494   96 RGLGPGEEVGLDDE-DEFIEVRWVPLDEALALVTA 129

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  16 LLARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGS---LMIACHATVKPGqtEIQV 92
Cdd:cd18886   15 LLNRNKKPNMGKWNGVGGKLEPGESPEECAIREVFEETGLELEDLQLRGIVTFPSFDGGedwLMYVFLAEAFSG--ELVE 92

                         90
                 ....*....|....*...
gi 545688245  93 NLRElETAAWFSHDEVAT 110
Cdd:cd18886   93 SDRE-GILAWVPIDWLLN 109

MutT homolog 2; MutT Homolog 2 (MTH2; EC 3.6.1.9), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 15/Nudt15, may catalyze the hydrolysis of nucleoside diphosphates, triphosphates including dGTP, dTTP, dCTP, their oxidized forms like 8-oxo-dGTP, and prodrug thiopurine derivatives 6-thio-dGTP and 6-thio-GTP. MTH2 may also play a role in DNA synthesis and cell cycle progression by stabilizing PCNA. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 545688245   4 VAITLVSDGTRCLLA-RQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYA 64
Cdd:cd04678    5 VGVIVLNDDGKVLLGrRKGSHGAGTWALPGGHLEFGESFEECAAREVLEETGLEIRNVRFLT 66

MutT homolog-1 (MTH1); MutT homolog-1 (MTH1; EC 3.6.1.- ), also called nucleoside diphosphate-linked moiety X)) motif 1 (Nudt1), is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 545688245   8 LVSDGTRCLLAR-QSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMIACH 80
Cdd:cd03427    8 VLRGDDRVLLGLkKRGFGAGKWNGFGGKVEPGETIEEAAVRELEEEAGLTATELEKVGRLKFEFPDDPEAMDVH 81

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   4 VAITLVSDGTRCLLARQSSFPK----GMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMIAC 79
Cdd:cd18882    4 AIAILYDDRGKVLLQLRDDKPGipypGYWGLFGGHLEPGETPEEAIRRELEEEIGYEPGEFRFFLLYTEDDGEDRIRHVF 83

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|...
gi 545688245  80 HA--TVKPGqteiQVNLRELETAAWFSHDEVatalkRKGPYTQQQNGTFPFWL 130
Cdd:cd18882   84 HAplDVDLS----DLVLNEGQALRLFSPEEI-----LQGPLYSNLAGILRPLL 127

ADP-ribose pyrophosphatase and similar proteins; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   4 VAITLVSDGtRCLLARQSSFP-KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMIACHAT 82
Cdd:cd04691    4 VGGVVVKEG-KVLLVKRAYGPgKGRWTLPGGFVEEGETLDEAIVREVLEETGIDAKPVGIIGVRSGVIRDGKSDNYVVFL 82

                         90       100
                 ....*....|....*....|....*..
gi 545688245  83 VKPGQTEIQVNLRELETAAWFSHDEVA 109
Cdd:cd04691   83 LEYVGGEPKPDERENSEAGFLTLEEAL 109

nucleoside diphosphate-linked moiety X)) motif 17; Nucleoside diphosphate-linked moiety X)) motif 17 (EC 3.6.1.-) encoded by the NUDT17 gene on chromosome 1q21.1 and encodes an enzyme thought to hydrolyse some nucleoside diphosphate derivatives. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245   4 VAITLVSDGTRCLLARQS----SFPkGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQY------YASQHWPFPSG 73
Cdd:cd04694    5 VVVLIEDSDDRVLLTRRAkhmrTFP-GVWVPPGGHVELGESLLEAGLRELQEETGLEVSDIQSlsllglWESVYPTLLSI 83

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*
gi 545688245  74 SLMIACHATV-------KPGQTEIQVNL--RELETAAWFSHDEVA 109
Cdd:cd04694   84 GLPKRHHIVVyylvklsESHENQEQLKLqeDEVDAAVWLPKSLLA 128

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20
                 ....*....|....*....|....*
gi 545688245  36 DIGESVEETIRREVAEEVGLEVESL 60
Cdd:cd04686   36 EFGESLEDALKREFAEETGMTVTSY 60

ADP-ribose pyrophosphatase, UDP-glucose pyrophosphatase, and similar proteins; ADP-ribose pyrophosphatase (ADPRase) ( NUDIX (Nucleoside diphosphate-linked moiety X)) motif 5; Nudt5) catalyzes the hydrolysis of ADP-ribose and a variety of additional ADP-sugar conjugates to AMP and ribose-5-phosphate. In humans, there are four distinct ADPRase activities, three putative cytosolic enzymes (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). Human ADPRase-II is also referred to as NUDT5. It lacks the N-terminal target sequence unique to mitochondrial ADPRase. The different cytosolic types are distinguished by their specificities for substrate and specific requirement for metal ions. NUDT5 forms a homodimer. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. UDP-glucose pyrophosphatase (UGPPase) (EC 3.6.1.45; also known as nucleoside diphosphate-linked moiety X)) motif 14; Nudt14) hydrolyzes the pyrophosphate of the nucleoside diphosphate sugar to generate glucose-1-P and UMP. In mammals, UDP-glucose is the glucosyl donor for the synthesis of the storage polysaccharide glycogen. UGPPase, as a regulator of UDP-glucose, could play a regulatory role, but it has been shown to prefer ADP-ribose over UDP-glucose. Like other members of the NUDIX hydrolase superfamily, it requires a divalent cation, such as Mg2+, for its activity. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 545688245   4 VAITLVSDGTRCLLARQssFPKGMYSAL----AGFCDIGESVEETIRREVAEEVGLEVESLQYYAS 65
Cdd:cd03424    5 VAVLAITDDGKVVLVRQ--YRHPVGRVLlelpAGKIDPGEDPEEAARRELEEETGYTAGDLELLGS 68

DR1025 and similar proteins; DR1025 from Deinococcus radiodurans, a member of the NUDIX hydrolase superfamily, show nucleoside triphosphatase and dinucleoside polyphosphate pyrophosphatase activities. Like other enzymes belonging to this superfamily, it requires a divalent cation, in this case Mg2+, for its activity. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. In general, substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  25 KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGSLMI--ACHATVKPGQTEIQVNLRELETAAW 102
Cdd:cd04700   42 AGLWHIPSGAVEDGENPQDAAVREACEETGLRVRLVKFLGAYLGRFPDGVLVLrhVWLAEPEPGQVLAPAFTDEIAEASF 121

                 ....*..
gi 545688245 103 FSHDEVA 109
Cdd:cd04700  122 VSREEFA 128

nudix hydrolase

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 545688245   6 ITLVSDGTRCLLARQ-SSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQY 62
Cdd:PLN02325  13 VVFLLKGNSVLLGRRrSSIGDSTFALPGGHLEFGESFEECAAREVKEETGLEIEKIEL 70

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 545688245  22 SFPkGMY--SAlAGFCDIGESVEETIRREVAEEVGLEVESLQY 62
Cdd:cd04692   52 DFP-GLWdiSA-AGHIDAGETYEEAAVRELEEELGLTVSPEDL 92

ADP-ribose pyrophosphatase and similar proteins; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  28 YSALAGFCDIGESVEETIRREVAEEVGLEVE--SLQY---YASQHWPFPSGSLMIACHATV---------KPGQTEIQ-V 92
Cdd:cd18880   27 YILPGGGQEHGETLPEALKRECLEETGLDVEvgDLLFvreYIGPNKPVHQVELFFLCTLEGgeltlgsdpDLNQVGVEwI 106

                 ....*
gi 545688245  93 NLREL 97
Cdd:cd18880  107 PLEEL 111

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 545688245   4 VAITLVSDGTRCLLARQSSFP-KGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYA 64
Cdd:cd04511    4 VVGCLPEWEGKVLLCRRAIEPrKGYWTLPAGFMELGETTEQGAARETREEAGARVEIGSLYA 65

CDP-choline pyrophosphatase; CDP-choline pyrophosphatase catalyzes the hydrolysis of CDP-choline to produce CMP and phosphocholine. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  11 DGTRCLLARQSSfpKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYA---SQHWPFPSG-----SLMIACHAT 82
Cdd:cd18890   12 DKEEILLVKEKE--DGKWTLPGGWADVGYTPTEVAAKEVEEETGLEVSPKKLLAildKRKHPHPPQptyvyKLFILCEIE 89

                         90       100
                 ....*....|....*....|....*
gi 545688245  83 VKPGQTEIqvnlrELETAAWFSHDE 107
Cdd:cd18890   90 GGELKPSF-----ETGEVRFFSENE 109

diadenosine tetraphosphate; Diadenosine tetraphosphate (Ap4A; EC 3.6.1.17), also called NUDIX (nucleoside diphosphate-linked moiety X)) motif 2/Nudt2, is a member of the NUDIX hydrolase superfamily. Ap4A hydrolases are well represented in a variety of prokaryotic and eukaryotic organisms. Phylogenetic analysis reveals two distinct subgroups where plant enzymes fall into one subfamily and fungi/animals/archaea enzymes, represented by this subfamily, fall into another. Bacterial enzymes are found in both subfamilies. Ap4A is a potential by-product of aminoacyl tRNA synthesis, and accumulation of Ap4A has been implicated in a range of biological events, such as DNA replication, cellular differentiation, heat shock, metabolic stress, and apoptosis. Ap4A hydrolase cleaves Ap4A asymmetrically into ATP and AMP. It is important in the invasive properties of bacteria and thus presents a potential target for inhibition of such invasive bacteria. Besides the signature NUDIX motif (G[X5]E[X7]REUXEEXGU, where U is Ile, Leu, or Val) that functions as a metal binding and catalytic site, and a required divalent cation, Ap4A hydrolase is structurally similar to the other members of the NUDIX hydrolase superfamily with some degree of variation. Several regions in the sequences are poorly defined and substrate and metal binding sites are only predicted based on kinetic studies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 545688245  22 SFPKGMysalagfCDIGESVEETIRREVAEEVGLEVESLQY 62
Cdd:cd03428   31 DFPKGH-------VEPGESELETALRETKEETGLTVDDLPP 64

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  36 DIGESVEETIRREVAEEVGLEV--ESLQYY------ASQHWPFPsgSLMIACHATVKPgqtEIQVNlRELETAAWFSHDE 107
Cdd:cd04690   33 EPGETPLQALVRELKEELGLDLdpDSLRFLgtfeapAANEPGTT--VRMTCFTADYDG---EPQPA-AEIEELRWLDPAD 106

Antisense Basic Fibroblast Growth Factor; Antisense Basic Fibroblast Growth Factor (ASFGF2; EC 3.6.1.-), also known as nucleoside diphosphate-linked moiety X)) motif 6/Nudt6, and similar proteins including peroxisomal coenzyme A diphosphatase/Nudt7 and mitochondrial coenzyme A diphosphatase/Nudt8. The Nudt6 gene overlaps and lies on the opposite strand from FGF2 gene, and is thought to be the FGF2 antisense gene. The two genes are independently transcribed, and their expression shows an inverse relationship, suggesting that this antisense transcript may regulate FGF2 expression. This gene has also been shown to have hormone-regulatory and antiproliferative actions in the pituitary that are independent of FGF2 expression. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 545688245  33 GFCDIGESVEETIRREVAEEVGLEVE--SLQYYASQHwPFPSG--SLMIACHATVKpGQTEIQVNLRELETAAWFSHDE 107
Cdd:cd04670   34 GLVDPGEDIGEAAVREVFEETGIDTEfvSILGFRHQH-PGRFGksDLYFVCRLRPL-SDEEIKICPEEIAEAKWMPLEE 110

NUDIX family Ndx2; NUDIX family protein Ndx2 found in Thermus thermophilus has ADP-ribose pyrophosphatase (ADPRase) as well as flavin adenine dinucleotide (FAD) activity. ADPRase (EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity.Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 545688245  16 LLARQSSFPKGMYSaL---AGFCDIGESVEETIRREVAEEVGLEVESLQY 62
Cdd:cd24161   18 VLVEQYRYPLGGWS-WeipAGGWPEGEDPEEAARRELREETGLRAERWTP 66

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30
                 ....*....|....*....|....*....|....*..
gi 545688245  38 GESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGS 74
Cdd:cd18875   39 GESFVDSVIREVKEETGLTIKNPELCGIKQWINPDGE 75

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 545688245  11 DGTRCLLARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQ 61
Cdd:cd04679   12 DGRLLLVLRLRAPEAGHWGLPGGKVDWLETVEDAVRREILEELGLEIELTR 62

ADP-ribose pyrophosphatase; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  16 LLARQSSfpkGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHW------PFPSG--SLMIACHATvkpgQ 87
Cdd:cd18889   16 LLVQEKD---GRWSLPGGWVDVNQSIKENTIKEAKEEAGLDVEPKRIIAVLDRnkhnkpPYAYGiyKIFVLCELL----G 88

                         90       100
                 ....*....|....*....|
gi 545688245  88 TEIQVNLrELETAAWFSHDE 107
Cdd:cd18889   89 GEFQPNI-ETIESGYFSLDE 107

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 545688245   2 APVAI--TLVSDGtRCLLARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVE 58
Cdd:cd04699    1 FPVSVkgVIFDNG-RVLLLRRSRAGAGEWELPGGRLEPGESPEEALKREVKEETGLDVS 58

NUDIX domain family found in Deinococcus radiodurans, and similar proteins; Deinococcus radiodurans protein DR_0079 is one of 21 NUDIX hydrolases that it encodes, and it has been observed to have a marked preference for cytosine ribonucleoside 5'-diphosphate (CDP) and cytosine ribonucleoside 5'-triphosphate (CTP), and for their corresponding deoxyribose nucleotides, dCDP and dCTP, to a lesser degree. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 545688245  18 ARQSSFPKGMYSALAGFCDIGESVEETIRREVAEEVGLEVESLQY 62
Cdd:cd24154   23 ADKRIFPLALDMSVGGHVSSGETYEQAFVRELQEELNLDLDQLSY 67

GDP-mannose hydrolase (GDPMK), and similar proteins; GDP-mannose hydrolase (GDPMK) is a NUDIX enzyme that uses GDP-mannose as the preferred substrate. It is distinct from Nudix ADP-ribose hydrolases. GDPMK and ADP-ribose pyrophosphatase seem to use similar catalytic mechanism. However, GDPMK hydrolysis does not rely on a single glutamate as the catalytic base; rather, it is dependent on residues that coordinate the magnesium ions and residues that position the substrate properly for catalysis. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 545688245  30 ALAGFCDiGESVEETIRREVAEEVGLEVESLQyYASQHWPFPSGS 74
Cdd:cd24157   41 ACAGLLD-GDDPEDCIRREAEEETGYRLGDLE-KVFTAYSSPGIV 83

uncharacterized NUDIX hydrolase subfamily; Contains a crystal structure of the NUDIX hydrolase from Nitrosomonas europaea, which has an unknown function. NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 545688245  32 AGFCDIGESVEETIRREVAEEVGLEVESLQYYASQHWPFPSGS---LMIACHATVKPgqteiQVNLRELET----AAWFS 104
Cdd:cd03675   30 AGHLEPGESLLEAAIRETLEETGWEVEPTALLGIYQWTAPDNGvtyLRFAFAGELLE-----HLPDQPLDSgiirAHWLT 104

                 ....*
gi 545688245 105 HDEVA 109
Cdd:cd03675  105 LEEIL 109

thiamine diphosphokinase Tnr3 from Schizosaccharomyces pombe and similar proteins; Tnr3 is a bifunctional enzyme composed of a C-terminal thiamine pyrophosphokinase domain, which transfers pyrophosphate from ATP to thiamine and an N-terminal NUDIX hydrolase domain that converts oxidized derivatives of thiamine diphosphate (oxothiamine and oxythiamine) to their respective monophosphates. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belong to this superfamily requires a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 545688245  11 DGTRCLLARQS----SFPkGMY-SALAGFCDIGESVEETIRREVAEEVGLEVE 58
Cdd:cd03676   19 DGLRLWVARRSatkaTYP-GKLdNLVAGGVPAGESPLETLVREAEEEAGLPED 70