NCBI Home Page NCBI Site Search page NCBI Guide that lists and describes the NCBI resources
Conserved domains on  [gi|16802390|ref|NP_463875|]
View 

sugar-phosphate isomerase [Listeria monocytogenes EGD-e]

Protein Classification

RpiB/LacA/LacB family sugar-phosphate isomerase( domain architecture ID 10002173)

RpiB/LacA/LacB family sugar-phosphate isomerase similar to ribose 5-phosphate isomerase B, which catalyzes the reversible conversion of ribose-5-phosphate to ribulose 5-phosphate

Graphical summary

 Zoom to residue level

show extra options »

Show site features     Horizontal zoom: ×

List of domain hits

 Name Accession Description Interval E-value
RpiB COG0698
Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate ...
 1-148 1.07e-77

Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate isomerase RpiB is part of the Pathway/BioSystem: Pentose phosphate pathway


:

Pssm-ID: 440462  Cd Length: 149  Bit Score: 226.89  E-value: 1.07e-77
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390   1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:COG0698   1 MKIAIGSDHAGFELKEAIKEYLEEKGHEVVDFGTYSEDSVDYPDFAIKVAEAVASGEADRGILICGTGIGMSIAANKVPG 80

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 16802390  81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQKNR 148
Cdd:COG0698  81 IRAALCHDPYSARLAREHNDANVLCLGARVIGPELAKEIVDAFLATEFEGGRHQRRVDKISELEKENA 148
 
Name Accession Description Interval E-value
RpiB COG0698
Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate ...
 1-148 1.07e-77

Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate isomerase RpiB is part of the Pathway/BioSystem: Pentose phosphate pathway


Pssm-ID: 440462  Cd Length: 149  Bit Score: 226.89  E-value: 1.07e-77
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390   1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:COG0698   1 MKIAIGSDHAGFELKEAIKEYLEEKGHEVVDFGTYSEDSVDYPDFAIKVAEAVASGEADRGILICGTGIGMSIAANKVPG 80

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 16802390  81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQKNR 148
Cdd:COG0698  81 IRAALCHDPYSARLAREHNDANVLCLGARVIGPELAKEIVDAFLATEFEGGRHQRRVDKISELEKENA 148
LacAB_rpiB pfam02502
Ribose/Galactose Isomerase; This family of proteins contains the sugar isomerase enzymes ...
 3-136 6.48e-71

Ribose/Galactose Isomerase; This family of proteins contains the sugar isomerase enzymes ribose 5-phosphate isomerase B (rpiB), galactose isomerase subunit A (LacA) and galactose isomerase subunit B (LacB).


Pssm-ID: 460573  Cd Length: 134  Bit Score: 209.17  E-value: 6.48e-71
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     3 IAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHGIR 82
Cdd:pfam02502   1 IAIGSDHAGFELKEEIKEYLEEKGHEVIDFGTYSEESVDYPDYAHKVAEAVASGEADRGILICGTGIGMSIAANKVPGIR 80

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....
gi 16802390    83 AAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAK 136
Cdd:pfam02502  81 AALCHDPYSAKLAREHNDANVLCLGARVIGPELAKEIVDAFLNTEFEGGRHQRR 134
PRK05571 PRK05571
ribose-5-phosphate isomerase B; Provisional
 1-146 3.48e-68

ribose-5-phosphate isomerase B; Provisional


Pssm-ID: 235509  Cd Length: 148  Bit Score: 202.70  E-value: 3.48e-68
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFE-DEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIH 79
Cdd:PRK05571   1 MKIAIGSDHAGFELKEEIIEHLEELGHEVIDLGPDSyDASVDYPDYAKKVAEAVVAGEADRGILICGTGIGMSIAANKVK 80

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 16802390   80 GIRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQK 146
Cdd:PRK05571  81 GIRAALCHDTYSAHLAREHNNANVLALGARVIGPELAKDIVDAFLATEFEGGRHQRRIDKIDEYEAQ 147
rpiB_lacA_lacB TIGR00689
sugar-phosphate isomerase, RpiB/LacA/LacB family; Proteins of known function in this family ...
 3-146 1.13e-47

sugar-phosphate isomerase, RpiB/LacA/LacB family; Proteins of known function in this family act as sugar (pentose and/or hexose)-phosphate isomerases, including the LacA and LacB subunits of galactose-6-phosphate isomerases from Gram-positive bacteria and RpiB. RpiB is the second ribose phosphate isomerase of E. coli. It lacks homology to RpiA, its inducer is unknown (but is not ribose), and it can be replaced by the homologous galactose-6-phosphate isomerase of Streptococcus mutans, all of which suggests that the ribose phosphate isomerase activity of RpiB is a secondary function. On the other hand, there appear to be a significant number of species which contain rpiB, lack rpiA and seem to require rpi activity in order to complete the pentose phosphate pathway.


Pssm-ID: 129772  Cd Length: 144  Bit Score: 150.61  E-value: 1.13e-47
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     3 IAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHGIR 82
Cdd:TIGR00689   1 IAIGSDHAGLELKSEIIEHLKQKGHEVIDCGTLYDERVDYPDYAKLVADKVVAGEVSLGILICGTGIGMSIAANKFKGIR 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 16802390    83 AAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQK 146
Cdd:TIGR00689  81 AALCVDEYTAALARQHNDANVLCLGSRVVGVELALSIVDAFLTTQFEGGRHQRRIDKIIEYERE 144
 
Name Accession Description Interval E-value
RpiB COG0698
Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate ...
 1-148 1.07e-77

Ribose 5-phosphate isomerase RpiB [Carbohydrate transport and metabolism]; Ribose 5-phosphate isomerase RpiB is part of the Pathway/BioSystem: Pentose phosphate pathway


Pssm-ID: 440462  Cd Length: 149  Bit Score: 226.89  E-value: 1.07e-77
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390   1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:COG0698   1 MKIAIGSDHAGFELKEAIKEYLEEKGHEVVDFGTYSEDSVDYPDFAIKVAEAVASGEADRGILICGTGIGMSIAANKVPG 80

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 16802390  81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQKNR 148
Cdd:COG0698  81 IRAALCHDPYSARLAREHNDANVLCLGARVIGPELAKEIVDAFLATEFEGGRHQRRVDKISELEKENA 148
LacAB_rpiB pfam02502
Ribose/Galactose Isomerase; This family of proteins contains the sugar isomerase enzymes ...
 3-136 6.48e-71

Ribose/Galactose Isomerase; This family of proteins contains the sugar isomerase enzymes ribose 5-phosphate isomerase B (rpiB), galactose isomerase subunit A (LacA) and galactose isomerase subunit B (LacB).


Pssm-ID: 460573  Cd Length: 134  Bit Score: 209.17  E-value: 6.48e-71
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     3 IAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHGIR 82
Cdd:pfam02502   1 IAIGSDHAGFELKEEIKEYLEEKGHEVIDFGTYSEESVDYPDYAHKVAEAVASGEADRGILICGTGIGMSIAANKVPGIR 80

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....
gi 16802390    83 AAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAK 136
Cdd:pfam02502  81 AALCHDPYSAKLAREHNDANVLCLGARVIGPELAKEIVDAFLNTEFEGGRHQRR 134
PRK05571 PRK05571
ribose-5-phosphate isomerase B; Provisional
 1-146 3.48e-68

ribose-5-phosphate isomerase B; Provisional


Pssm-ID: 235509  Cd Length: 148  Bit Score: 202.70  E-value: 3.48e-68
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFE-DEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIH 79
Cdd:PRK05571   1 MKIAIGSDHAGFELKEEIIEHLEELGHEVIDLGPDSyDASVDYPDYAKKVAEAVVAGEADRGILICGTGIGMSIAANKVK 80

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 16802390   80 GIRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQK 146
Cdd:PRK05571  81 GIRAALCHDTYSAHLAREHNNANVLALGARVIGPELAKDIVDAFLATEFEGGRHQRRIDKIDEYEAQ 147
PTZ00215 PTZ00215
ribose 5-phosphate isomerase; Provisional
 1-147 1.70e-48

ribose 5-phosphate isomerase; Provisional


Pssm-ID: 185516  Cd Length: 151  Bit Score: 153.25  E-value: 1.70e-48
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKN--IEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKI 78
Cdd:PTZ00215   3 KKVAIGSDHAGFDLKNEIIDYIKNKGkeYKIEDMGTYTAESVDYPDFAEKVCEEVLKGEADTGILVCGSGIGISIAANKV 82

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 16802390   79 HGIRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQKN 147
Cdd:PTZ00215  83 KGIRCALCHDHYTARMSRQHNNANVLAFGGRTTGIEVAKEIIDTFLSTPFEGGRHTERIDKISAIEEEN 151
rpiB_lacA_lacB TIGR00689
sugar-phosphate isomerase, RpiB/LacA/LacB family; Proteins of known function in this family ...
 3-146 1.13e-47

sugar-phosphate isomerase, RpiB/LacA/LacB family; Proteins of known function in this family act as sugar (pentose and/or hexose)-phosphate isomerases, including the LacA and LacB subunits of galactose-6-phosphate isomerases from Gram-positive bacteria and RpiB. RpiB is the second ribose phosphate isomerase of E. coli. It lacks homology to RpiA, its inducer is unknown (but is not ribose), and it can be replaced by the homologous galactose-6-phosphate isomerase of Streptococcus mutans, all of which suggests that the ribose phosphate isomerase activity of RpiB is a secondary function. On the other hand, there appear to be a significant number of species which contain rpiB, lack rpiA and seem to require rpi activity in order to complete the pentose phosphate pathway.


Pssm-ID: 129772  Cd Length: 144  Bit Score: 150.61  E-value: 1.13e-47
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     3 IAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHGIR 82
Cdd:TIGR00689   1 IAIGSDHAGLELKSEIIEHLKQKGHEVIDCGTLYDERVDYPDYAKLVADKVVAGEVSLGILICGTGIGMSIAANKFKGIR 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 16802390    83 AAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEIDQK 146
Cdd:TIGR00689  81 AALCVDEYTAALARQHNDANVLCLGSRVVGVELALSIVDAFLTTQFEGGRHQRRIDKIIEYERE 144
rpiB TIGR01120
ribose 5-phosphate isomerase B; Involved in the non-oxidative branch of the pentose phospate ...
 2-143 2.51e-42

ribose 5-phosphate isomerase B; Involved in the non-oxidative branch of the pentose phospate pathway. [Energy metabolism, Pentose phosphate pathway]


Pssm-ID: 130190  Cd Length: 143  Bit Score: 137.35  E-value: 2.51e-42
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     2 KIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHGI 81
Cdd:TIGR01120   1 KIAIGSDHAGFILKEEIKAFLVERGVKVIDKGTWSSERTDYPHYAKQVALAVAGGEVDGGILICGTGIGMSIAANKFAGI 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 16802390    82 RAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEI 143
Cdd:TIGR01120  81 RAALCSEPYMAQMSRLHNDANVLCLGERVVGLELAKSIVDAWLGTQFEGGRHQQRVEAITAI 142
PRK08622 PRK08622
galactose-6-phosphate isomerase subunit LacB; Reviewed
 1-128 1.51e-28

galactose-6-phosphate isomerase subunit LacB; Reviewed


Pssm-ID: 181506  Cd Length: 171  Bit Score: 102.80  E-value: 1.51e-28
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:PRK08622   1 MKIAIGCDHIVTDEKMAVSDYLKSKGHEVIDVGTYDFTRTHYPIFGKKVGEAVASGEADLGVCICGTGVGISNAVNKVPG 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 16802390   81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDF 128
Cdd:PRK08622  81 IRSALVRDMTSALYAKEELNANVIGFGGKITGELLMCDIIDAFINAEY 128
RPI_actino TIGR02133
ribose 5-phosphate isomerase; This family is a member of the RpiB/LacA/LacB subfamily ...
 1-142 1.62e-28

ribose 5-phosphate isomerase; This family is a member of the RpiB/LacA/LacB subfamily (TIGR00689) but lies outside the RpiB equivalog (TIGR01120) which is also a member of that subfamily. Ribose 5-phosphate isomerase is an essential enzyme of the pentose phosphate pathway; a pathway that appears to be present in the actinobacteria. The only candidates for ribose 5-phosphate isomerase in the Actinobacteria are members of this family.


Pssm-ID: 273989  Cd Length: 148  Bit Score: 102.15  E-value: 1.62e-28
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390     1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFE-DEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIH 79
Cdd:TIGR02133   1 MRVVLGHDHAGFEYKEALWLDLAAHEPEVCDVGVYDaDDDDDYPCFCIAAAEAVARDAADLGIVIGGSGNGEAIAANKVK 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 16802390    80 GIRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSG-GRSQAKVDLMEE 142
Cdd:TIGR02133  81 GARAALAWDTASAGRARLHNNANVVGAGMRMHGLEEAFRLVFEFLGFEFDArSRHARRIDSISE 144
PRK08621 PRK08621
galactose-6-phosphate isomerase subunit LacA; Reviewed
 1-141 5.79e-28

galactose-6-phosphate isomerase subunit LacA; Reviewed


Pssm-ID: 181505  Cd Length: 142  Bit Score: 100.56  E-value: 5.79e-28
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAekVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:PRK08621   1 MAIIIGADKAGFELKEVVKDYLEDNKYEVVDVTEEGAEDFVDSTLA--VAKEVNKSEDNLGIVIDAYGAGSFMVATKIKG 78

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 16802390   81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLME 141
Cdd:PRK08621  79 MVAAEVSDERSAYMTRGHNNARMITMGSEIVGDGLAKNIIKGFVEGKYDGGRHQIRVDMLN 139
PRK12615 PRK12615
galactose-6-phosphate isomerase subunit LacB; Reviewed
 1-128 2.42e-22

galactose-6-phosphate isomerase subunit LacB; Reviewed


Pssm-ID: 171610  Cd Length: 171  Bit Score: 87.00  E-value: 2.42e-22
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVLYPSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:PRK12615   1 MKIAIGCDHIVTNEKMAVSDFLKSKGYDVIDCGTYDHTRTHYPIFGKKVGEAVVNGQADLGVCICGTGVGINNAVNKVPG 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 16802390   81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDF 128
Cdd:PRK12615  81 IRSALVRDMTTALYAKEELNANVIGFGGKITGELLMCDIIDAFIKAEY 128
PRK12613 PRK12613
galactose-6-phosphate isomerase subunit LacA; Provisional
 1-143 2.28e-18

galactose-6-phosphate isomerase subunit LacA; Provisional


Pssm-ID: 171609  Cd Length: 141  Bit Score: 76.12  E-value: 2.28e-18
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 16802390    1 MKIAIGCDEMGYELKQTLITRLKEKNIEFTDFGSFEDEKVlypSIAEKVALEVKNNDYDRGILICGTGIGMAITANKIHG 80
Cdd:PRK12613   1 MAIILGADAHGNALKELIKSFLQEEGYDIIDVTDINSDFI---DNTLAVAKAVNEAEGRLGIMVDAYGAGPFMVATKLKG 77

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 16802390   81 IRAAQIHDSYSAERARKSNDAHIMTMGALVIGPSLAVSLLDTWLDSDFSGGRSQAKVDLMEEI 143
Cdd:PRK12613  78 MVAAEVSDERSAYMTRGHNNARMITMGAEIVGPELAKNIAKGFVTGPYDGGRHQIRVDMLNKM 140
 
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