NCBI Home Page NCBI Site Search page NCBI Guide that lists and describes the NCBI resources
Conserved domains on  [gi|1907133151|ref|XP_036017622|]
View 

cytosolic purine 5'-nucleotidase isoform X3 [Mus musculus]

Protein Classification

Graphical summary

 Zoom to residue level

show extra options »

Show site features     Horizontal zoom: ×

List of domain hits

 Name Accession Description Interval E-value
5_nucleotid super family cl17687
5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, ...
 1-298 8.01e-159

5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, such as purine 5'-nucleotidase EC:3.1.3.5.


The actual alignment was detected with superfamily member pfam05761:

Pssm-ID: 473086  Cd Length: 445  Bit Score: 453.13  E-value: 8.01e-159
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVG-KVFLATNSDYKYTDKIMTYLFDFPHGP 79
Cdd:pfam05761 140 YDYESLYQDVREAVDLVHRDGSLKKEVAADPEKYIEKDPELPPLLERLREAGkKLFLLTNSDYDYTNKGMNYLLGGFLPK 219

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 kpgssHRPWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIGTYTGPLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:pfam05761 220 -----YKDWRDLFDVVIVGARKPLFFTEGRPLREVDTETGRLLWGNVTGPLEKGKVYQGGSLDHFHKLLGWRGSEVLYVG 294

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELAQELHVWTDKS--SLFEELQSLDIFLAELYKHLDSSSNE---------RPDISSI 228
Cdd:pfam05761 295 DHIYGDILRSKKKLGWRTALVIPELEREIEVLNSKRyrKELAELQTLRELLEDEYKDLDSSLAQqsdekleelPADLEEL 374

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1907133151 229 QRRIKKVTHDMDMCY-GMMGSLFRSGSRQTLFASQVMRYADLYAASFINLLYYPFSYLFRAAHVLMPHEST 298
Cdd:pfam05761 375 RKEIRELRREMKELFnPQWGSLFRTGSNPSYFARQVERYADLYTSSVSNLLNYSPNYYFRPPRDLLPHEST 445
 
Name Accession Description Interval E-value
5_nucleotid pfam05761
5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, ...
 1-298 8.01e-159

5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, such as purine 5'-nucleotidase EC:3.1.3.5.


Pssm-ID: 461733  Cd Length: 445  Bit Score: 453.13  E-value: 8.01e-159
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVG-KVFLATNSDYKYTDKIMTYLFDFPHGP 79
Cdd:pfam05761 140 YDYESLYQDVREAVDLVHRDGSLKKEVAADPEKYIEKDPELPPLLERLREAGkKLFLLTNSDYDYTNKGMNYLLGGFLPK 219

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 kpgssHRPWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIGTYTGPLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:pfam05761 220 -----YKDWRDLFDVVIVGARKPLFFTEGRPLREVDTETGRLLWGNVTGPLEKGKVYQGGSLDHFHKLLGWRGSEVLYVG 294

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELAQELHVWTDKS--SLFEELQSLDIFLAELYKHLDSSSNE---------RPDISSI 228
Cdd:pfam05761 295 DHIYGDILRSKKKLGWRTALVIPELEREIEVLNSKRyrKELAELQTLRELLEDEYKDLDSSLAQqsdekleelPADLEEL 374

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1907133151 229 QRRIKKVTHDMDMCY-GMMGSLFRSGSRQTLFASQVMRYADLYAASFINLLYYPFSYLFRAAHVLMPHEST 298
Cdd:pfam05761 375 RKEIRELRREMKELFnPQWGSLFRTGSNPSYFARQVERYADLYTSSVSNLLNYSPNYYFRPPRDLLPHEST 445
HAD_cN-II cd07522
cytosolic 5'-nucleotidase II (cN-II) similar to human NT5DC1 (5'-nucleotidase ...
 1-272 2.82e-96

cytosolic 5'-nucleotidase II (cN-II) similar to human NT5DC1 (5'-nucleotidase domain-containing protein 1) and NT5DC2; Cytosolic 5'-nucleotidase II (cN-II), also known as purine 5'-nucleotidase, IMP-GMP specific nucleotidase, or high Km 5prime-nucleotidase, catalyzes the dephosphorylation of 6-hydroxypurine nucleoside monophosphates. It is ubiquitously expressed and likely to play an important role in the regulation of purine nucleotide interconversions and in the regulation of IMP and GMP pools within the cell. It is also acts as a phosphotransferase, catalyzing the reverse reaction, the transfer of a phosphate from a monophosphate substrate to a nucleoside acceptor, to form a nucleoside monophosphate. The nucleoside acceptor is preferentially inosine and deoxyinosine, phosphate donors include any 6-hydroxypurine monophosphate substrate of the nucleotidase reaction. Both the dephosphorylation and phosphotransferase reactions are allosterically activated by adenine-based nucleotides and 2,3-bisphosphoglycerate. Members of this family belong to the haloacid dehalogenase-like (HAD) hydrolases, a large superfamily of diverse enzymes that catalyze carbon or phosphoryl group transfer reactions on a range of substrates, using an active site aspartate in nucleophilic catalysis. Members of this superfamily include 2-L-haloalkanoic acid dehalogenase, azetidine hydrolase, phosphonoacetaldehyde hydrolase, phosphoserine phosphatase, phosphomannomutase, P-type ATPases and many others. HAD hydrolases are found in all three kingdoms of life, and most genomes are predicted to contain multiple HAD-like proteins. Members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. HAD hydrolases are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.


Pssm-ID: 319824  Cd Length: 352  Bit Score: 290.33  E-value: 2.82e-96
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVG-KVFLATNSDYKYTDKIMTYLFDFPHGp 79
Cdd:cd07522   148 MSYRSIYQDVRAAVDWVHSKGLLKKKIMQDPERYVLRDPELPLLLSRLREAGkKLFLLTNSDYSYTNKGMKYLLGGFLP- 226

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 kpgsSHRPWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIgTYTGPLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:cd07522   227 ----KHRDWRDYFDVVIVDARKPGFFTEGTPFREVDTETGQLKI-TKVGPLEKGKVYSGGNLKQFTELLGWRGKEVLYFG 301

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELaqelhvwtdksslfeelqsldiflaelykhldsssnerpdissiqrrikkvthdm 239
Cdd:cd07522   302 DHIYSDILKSKKRHGWRTALIVPEL------------------------------------------------------- 326

                         250       260       270
                  ....*....|....*....|....*....|...
gi 1907133151 240 dmcygmmGSLFRSGSRQTLFASQVMRYADLYAA 272
Cdd:cd07522   327 -------GSLFRTGSNPTYFSSQVERYADLYTS 352
HAD-IG-Ncltidse TIGR02244
HAD superfamily (subfamily IG) hydrolase, 5'-nucleotidase; This model includes a 5 ...
 1-201 2.64e-93

HAD superfamily (subfamily IG) hydrolase, 5'-nucleotidase; This model includes a 5'-nucleotidase specific for purines (IMP and GMP). These enzymes are members of the Haloacid Dehalogenase (HAD) superfamily. HAD members are recognized by three short motifs {hhhhDxDx(T/V)}, {hhhh(T/S)}, and either {hhhh(D/E)(D/E)x(3-4)(G/N)} or {hhhh(G/N)(D/E)x(3-4)(D/E)} (where "h" stands for a hydrophobic residue). Crystal structures of many HAD enzymes has verified PSI-PRED predictions of secondary structural elements which show each of the "hhhh" sequences of the motifs as part of beta sheets. This subfamily of enzymes is part of "Subfamily I" of the HAD superfamily by virtue of a "cap" domain in between motifs 1 and 2. This subfamily's cap domain has a different predicted secondary structure than all other known HAD enzymes and thus has been designated "subfamily IG". This domain appears to consist of a mixed alpha/beta fold. A Pfam model (pfam05761) detects an identical range of sequences above the trusted cutoff, but does not model the N-terminal motif 1 region. A TIGRFAMs model (TIGR01993) represents a (putative) family of _pyrimidine_ 5'-nucleotidases which are also subfamily I HAD's, which should not be confused with the current model.


Pssm-ID: 274052  Cd Length: 343  Bit Score: 282.67  E-value: 2.64e-93
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVGK-VFLATNSDYKYTDKIMTYLFDFPHGP 79
Cdd:TIGR02244 149 FDYRQIYQDVRDALDWVHRKGSLKKKVMENPEKYVLRDPKLPLFLSKLKEHGKkLFLLTNSDYDYTDKGMKYLLGPFLGE 228

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 KPgsshrpWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIGTYTGpLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:TIGR02244 229 HD------WRDYFDVVIVDARKPGFFTEGRPFRQVDVETGSLKWGEVDG-LEPGKVYSGGSLKQFHELLKWRGKEVLYFG 301

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|..
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELAQELHVWTDKSSLFEEL 201
Cdd:TIGR02244 302 DHIYGDLLRSKKKRGWRTAAIIPELEQEVGILTNSKSLREEL 343
 
Name Accession Description Interval E-value
5_nucleotid pfam05761
5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, ...
 1-298 8.01e-159

5' nucleotidase family; This family of eukaryotic proteins includes 5' nucleotidase enzymes, such as purine 5'-nucleotidase EC:3.1.3.5.


Pssm-ID: 461733  Cd Length: 445  Bit Score: 453.13  E-value: 8.01e-159
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVG-KVFLATNSDYKYTDKIMTYLFDFPHGP 79
Cdd:pfam05761 140 YDYESLYQDVREAVDLVHRDGSLKKEVAADPEKYIEKDPELPPLLERLREAGkKLFLLTNSDYDYTNKGMNYLLGGFLPK 219

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 kpgssHRPWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIGTYTGPLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:pfam05761 220 -----YKDWRDLFDVVIVGARKPLFFTEGRPLREVDTETGRLLWGNVTGPLEKGKVYQGGSLDHFHKLLGWRGSEVLYVG 294

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELAQELHVWTDKS--SLFEELQSLDIFLAELYKHLDSSSNE---------RPDISSI 228
Cdd:pfam05761 295 DHIYGDILRSKKKLGWRTALVIPELEREIEVLNSKRyrKELAELQTLRELLEDEYKDLDSSLAQqsdekleelPADLEEL 374

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1907133151 229 QRRIKKVTHDMDMCY-GMMGSLFRSGSRQTLFASQVMRYADLYAASFINLLYYPFSYLFRAAHVLMPHEST 298
Cdd:pfam05761 375 RKEIRELRREMKELFnPQWGSLFRTGSNPSYFARQVERYADLYTSSVSNLLNYSPNYYFRPPRDLLPHEST 445
HAD_cN-II cd07522
cytosolic 5'-nucleotidase II (cN-II) similar to human NT5DC1 (5'-nucleotidase ...
 1-272 2.82e-96

cytosolic 5'-nucleotidase II (cN-II) similar to human NT5DC1 (5'-nucleotidase domain-containing protein 1) and NT5DC2; Cytosolic 5'-nucleotidase II (cN-II), also known as purine 5'-nucleotidase, IMP-GMP specific nucleotidase, or high Km 5prime-nucleotidase, catalyzes the dephosphorylation of 6-hydroxypurine nucleoside monophosphates. It is ubiquitously expressed and likely to play an important role in the regulation of purine nucleotide interconversions and in the regulation of IMP and GMP pools within the cell. It is also acts as a phosphotransferase, catalyzing the reverse reaction, the transfer of a phosphate from a monophosphate substrate to a nucleoside acceptor, to form a nucleoside monophosphate. The nucleoside acceptor is preferentially inosine and deoxyinosine, phosphate donors include any 6-hydroxypurine monophosphate substrate of the nucleotidase reaction. Both the dephosphorylation and phosphotransferase reactions are allosterically activated by adenine-based nucleotides and 2,3-bisphosphoglycerate. Members of this family belong to the haloacid dehalogenase-like (HAD) hydrolases, a large superfamily of diverse enzymes that catalyze carbon or phosphoryl group transfer reactions on a range of substrates, using an active site aspartate in nucleophilic catalysis. Members of this superfamily include 2-L-haloalkanoic acid dehalogenase, azetidine hydrolase, phosphonoacetaldehyde hydrolase, phosphoserine phosphatase, phosphomannomutase, P-type ATPases and many others. HAD hydrolases are found in all three kingdoms of life, and most genomes are predicted to contain multiple HAD-like proteins. Members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. HAD hydrolases are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.


Pssm-ID: 319824  Cd Length: 352  Bit Score: 290.33  E-value: 2.82e-96
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVG-KVFLATNSDYKYTDKIMTYLFDFPHGp 79
Cdd:cd07522   148 MSYRSIYQDVRAAVDWVHSKGLLKKKIMQDPERYVLRDPELPLLLSRLREAGkKLFLLTNSDYSYTNKGMKYLLGGFLP- 226

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 kpgsSHRPWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIgTYTGPLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:cd07522   227 ----KHRDWRDYFDVVIVDARKPGFFTEGTPFREVDTETGQLKI-TKVGPLEKGKVYSGGNLKQFTELLGWRGKEVLYFG 301

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELaqelhvwtdksslfeelqsldiflaelykhldsssnerpdissiqrrikkvthdm 239
Cdd:cd07522   302 DHIYSDILKSKKRHGWRTALIVPEL------------------------------------------------------- 326

                         250       260       270
                  ....*....|....*....|....*....|...
gi 1907133151 240 dmcygmmGSLFRSGSRQTLFASQVMRYADLYAA 272
Cdd:cd07522   327 -------GSLFRTGSNPTYFSSQVERYADLYTS 352
HAD-IG-Ncltidse TIGR02244
HAD superfamily (subfamily IG) hydrolase, 5'-nucleotidase; This model includes a 5 ...
 1-201 2.64e-93

HAD superfamily (subfamily IG) hydrolase, 5'-nucleotidase; This model includes a 5'-nucleotidase specific for purines (IMP and GMP). These enzymes are members of the Haloacid Dehalogenase (HAD) superfamily. HAD members are recognized by three short motifs {hhhhDxDx(T/V)}, {hhhh(T/S)}, and either {hhhh(D/E)(D/E)x(3-4)(G/N)} or {hhhh(G/N)(D/E)x(3-4)(D/E)} (where "h" stands for a hydrophobic residue). Crystal structures of many HAD enzymes has verified PSI-PRED predictions of secondary structural elements which show each of the "hhhh" sequences of the motifs as part of beta sheets. This subfamily of enzymes is part of "Subfamily I" of the HAD superfamily by virtue of a "cap" domain in between motifs 1 and 2. This subfamily's cap domain has a different predicted secondary structure than all other known HAD enzymes and thus has been designated "subfamily IG". This domain appears to consist of a mixed alpha/beta fold. A Pfam model (pfam05761) detects an identical range of sequences above the trusted cutoff, but does not model the N-terminal motif 1 region. A TIGRFAMs model (TIGR01993) represents a (putative) family of _pyrimidine_ 5'-nucleotidases which are also subfamily I HAD's, which should not be confused with the current model.


Pssm-ID: 274052  Cd Length: 343  Bit Score: 282.67  E-value: 2.64e-93
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151   1 MSYRSMFQDVRDAVDWVHYKGSLKEKTVENLEKYVVKDGKLPLLLSRMKEVGK-VFLATNSDYKYTDKIMTYLFDFPHGP 79
Cdd:TIGR02244 149 FDYRQIYQDVRDALDWVHRKGSLKKKVMENPEKYVLRDPKLPLFLSKLKEHGKkLFLLTNSDYDYTDKGMKYLLGPFLGE 228

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  80 KPgsshrpWQSYFDLILVDARKPLFFGEGTVLRQVDTKTGKLKIGTYTGpLQHGIVYSGGSSDTICDLLGAKGKDILYIG 159
Cdd:TIGR02244 229 HD------WRDYFDVVIVDARKPGFFTEGRPFRQVDVETGSLKWGEVDG-LEPGKVYSGGSLKQFHELLKWRGKEVLYFG 301

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|..
gi 1907133151 160 DHIFGDILKSKKRQGWRTFLVIPELAQELHVWTDKSSLFEEL 201
Cdd:TIGR02244 302 DHIYGDLLRSKKKRGWRTAAIIPELEQEVGILTNSKSLREEL 343
HAD_like cd01427
Haloacid dehalogenase-like hydrolases; The haloacid dehalogenase-like (HAD) superfamily ...
 44-180 9.12e-03

Haloacid dehalogenase-like hydrolases; The haloacid dehalogenase-like (HAD) superfamily includes L-2-haloacid dehalogenase, epoxide hydrolase, phosphoserine phosphatase, phosphomannomutase, phosphoglycolate phosphatase, P-type ATPase, and many others. This superfamily includes a variety of enzymes that catalyze the cleavage of substrate C-Cl, P-C, and P-OP bonds via nucleophilic substitution pathways. All of which use a nucleophilic aspartate in their phosphoryl transfer reaction. They catalyze nucleophilic substitution reactions at phosphorus or carbon centers, using a conserved Asp carboxylate in covalent catalysis. All members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. Members of this superfamily are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.


Pssm-ID: 319763 [Multi-domain]  Cd Length: 106  Bit Score: 35.45  E-value: 9.12e-03
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907133151  44 LLSRMKEVG-KVFLATNSDYKYTDKIMTYLFdfphgpkpgsshrpWQSYFDLIlvdarkplFFGEGTVLRQVDTKtgklk 122
Cdd:cd01427    15 LLKRLRAAGiKLAIVTNRSREALRALLEKLG--------------LGDLFDGI--------IGSDGGGTPKPKPK----- 67

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1907133151 123 igtytgPLQHgivysggssdtICDLLGAKGKDILYIGDHIFgDILKSKKRqGWRTFLV 180
Cdd:cd01427    68 ------PLLL-----------LLLKLGVDPEEVLFVGDSEN-DIEAARAA-GGRTVAV 106
 
Blast search parameters
Data Source: Precalculated data, version = cdd.v.3.21
Preset Options:Database: CDSEARCH/cdd   Low complexity filter: no  Composition Based Adjustment: yes   E-value threshold: 0.01

References:

  • Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
  • Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
  • Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
Help | Disclaimer | Write to the Help Desk
NCBI | NLM | NIH