NUDIX domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2006370613 195 QFVAIKRRD---CGEWAIPGGMVDPGEKITATLKREFEEEA-LNSLQKSPEEKAKLEKQLQKLFSQEHLVVYRgYVDDPR 270
Cdd:pfam00293  16 RVLLVRRSKkpfPGWWSLPGGKVEPGETPEEAARRELEEETgLEPELLELLGSLHYLAPFDGRFPDEHEILYV-FLAEVE 94

                          90
                  ....*....|....*
gi 2006370613 271 NTDNAWMETEAVNYH 285
Cdd:pfam00293  95 GELEPDPDGEVEEVR 109

nucleoside triphosphatase NudI; Provisional

                          10        20
                  ....*....|....*....|....*..
gi 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:PRK15472   31 GQWALSGGGVEPGERIEEALRREIREE 57

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
                  ....*....|....*....|....*....|....*....|.
gi 2006370613 195 QFVAIKRRD---CGEWAIPGGMVDPGEKITATLKREFEEEA 232
Cdd:cd02883    13 RVLLVRRSDgpgPGGWELPGGGVEPGETPEEAAVREVREET 53

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 2006370613 200 KRRDCGEWAIPGGMVDPGEKITATLKREFEEEA 232
Cdd:cd04677    30 KRTDTGDWGLPGGAMELGESLEETARREVFEET 62

bifunctional NMN adenylyltransferase/ADP-ribose pyrophosphatase and similar proteins; Bacterial NadM-Nudix is a bifunctional enzyme containing a nicotinamide mononucleotide (NMN) adenylyltransferase (NMNAT) and an ADP-ribose pyrophosphatase (ADPRase) domain. NMNAT was initially identified as an NAD+ synthase that catalyzes the reversible conversion of NMN to NAD+ in the final step of both the de novo biosynthesis and salvage pathways in most organisms across all three kingdoms of life ADPRase is a member of the NUDIX family proteins, catalyzes the metal-induced and concerted general acid-base hydrolysis of ADP ribose (ADPR) into AMP and ribose-5'-phosphate (R5P). Additional members in this cd include bacterial transcriptional regulator, NrtR, which represses the transcription of NAD biosynthetic genes in vitro and adenosine diphosphate ribose (ADPR), as well as NadQ, a NUDIX-like ATP-responsive regulator of NAD biosynthesis. 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, U=I, L or V) which functions as 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 _ "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 2006370613 164 PNHAADPVVTRWKRDGsgnkiahpvsgkniLQFVAIKRRDC---GEWAIPGGMVDPGEKITATLKREFEEEAlnSLqksp 240
Cdd:cd18873     1 PSVTVDCVIFGFDDGE--------------LKVLLIKRKNEpfkGGWALPGGFVREDETLEDAARRELREET--GL---- 60

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2006370613 241 eekaklekqlqKLFSQEHLVVYrGYVD-DPRntdnAWMETEA----VNYhdetgetmDNLPLEAGDDAGVVKWVDISEKL 315
Cdd:cd18873    61 -----------KDIYLEQLGTF-GDPDrDPR----GRVISVAylalVPE--------EDLAPKAGDDAAEARWFPVDELL 116

                  .
gi 2006370613 316 E 316
Cdd:cd18873   117 P 117

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 2006370613 199 IKRR---DCGEWAIPGGMVDPGEKITATLKREFEEEalnslqkspeekAKLEKQLQKLFsqehlvvyrgYVDDPRNTDna 275
Cdd:cd04673    17 VRRGnppDAGLWSFPGGKVELGETLEDAALRELREE------------TGLEAEVVGLL----------TVVDVIERD-- 72

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 2006370613 276 wmETEAVNYH---------DETGEtmdnlpLEAGDDAGVVKWVDISE 313
Cdd:cd04673    73 --EAGRVRFHyvildflaeWVSGE------PVAGDDALDARWFSLEE 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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEEalnsLQKSPEekaklekQLQKLFSQEHLVVYRGyvddprntdnawmeteaVNY 284
Cdd:cd04681    31 GKLDLPGGFVDPGESAEEALRRELREE----LGLKIP-------KLRYLCSLPNTYLYKG-----------------ITY 82

                          90       100       110
                  ....*....|....*....|....*....|....*....
gi 2006370613 285 HdetgeTMD-----NLP-----LEAGDDAGVVKWVDISE 313
Cdd:cd04681    83 K-----TCDlfftaELDekpklKKAEDEVAELEWLDLEE 116

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 2006370613 200 KRRDCGEWAIPGGMVDPGEKITATLKREFEEEA 232
Cdd:cd18879    36 RRADNGRWTPVTGIVEPGEQPADAAVREVLEET 68

Predicted NTP pyrophosphohydrolase, NUDIX family [Nucleotide transport and metabolism, General function prediction only];

                          10        20        30
                  ....*....|....*....|....*....|..
gi 2006370613 200 KRRDCGEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:COG4119    31 ARKDEGAWSIPKGEYEPGEDPLAAARREFAEE 62

nucleoside triphosphatase NudI; Provisional

                          10        20
                  ....*....|....*....|....*..
gi 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:PRK15472   31 GQWALSGGGVEPGERIEEALRREIREE 57

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 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEEA 232
Cdd:cd04686    26 GRYDLPGGSQEFGESLEDALKREFAEET 53

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
                  ....*....|....*....|....*....|....*...
gi 2006370613 195 QF-VAIKRRdcgEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:cd03424    21 QYrHPVGRV---LLELPAGKIDPGEDPEEAARRELEEE 55

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 2006370613 189 SGKNILQfvaikRRDC-------GEWAIPGGMVDPGEKITATLKREFEEEAlnSLQKSPEEKAKL 246
Cdd:cd18882    12 RGKVLLQ-----LRDDkpgipypGYWGLFGGHLEPGETPEEAIRRELEEEI--GYEPGEFRFFLL 69

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 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:cd18874    26 DLYGIPGGKVEWGETLEEALKREVKEE 52

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 2006370613 203 DCGEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:cd04688    22 DDDYYRLPGGRVEFGETSEDALVREFKEE 50

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 2006370613 207 WAIPGGMVDPGEKITATLKREFEEE 231
Cdd:cd18876    25 WELPGGVVEAGESPLQAARREVREE 49

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 2006370613 207 WAIPGGMVDPGEKITATLKREFEEEA 232
Cdd:cd04680    25 WYLPGGGVDKGETAEEAARRELREEA 50

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
                  ....*....|....*....|....*..
gi 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:cd04679    27 GHWGLPGGKVDWLETVEDAVRREILEE 53

Nudix family hydrolase;

                          10        20
                  ....*....|....*....|....*..
gi 2006370613 205 GEWAIPGGMVDPGEKITATLKREFEEE 231
Cdd:PRK08999   32 GLWEFPGGKVEPGETVEQALARELQEE 58