NCBI Home Page NCBI Site Search page NCBI Guide that lists and describes the NCBI resources
Conserved domains on  [gi|1573074289|gb|QBC19705|]
View 

cytochrome b, partial (mitochondrion) [Eremogryllodes dilutus]

Protein Classification

cytochrome b( domain architecture ID 999997)

cytochrome b is a component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex) that is part of the mitochondrial respiratory chain; contributes to the generation of a proton gradient across the mitochondrial membrane that is then used for ATP synthesis

CATH:  1.20.810.10
Gene Symbol:  CYTB
PubMed:  2509716|8329437
SCOP:  4002208

Graphical summary

 Zoom to residue level

show extra options »

Show site features     Horizontal zoom: ×

List of domain hits

Name Accession Description Interval E-value
CYTB super family cl33360
cytochrome b; Provisional
2-93 1.29e-36

cytochrome b; Provisional


The actual alignment was detected with superfamily member MTH00156:

Pssm-ID: 214440 [Multi-domain]  Cd Length: 356  Bit Score: 126.05  E-value: 1.29e-36
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00156  150 LVQWIWGGFSVDNATLTRFFTFHFLLPFIILAMVMIHLLFLHQTGSNNPLGLNSNIDKIPFHPYFTFKDLVGFIIMLMLL 229
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00156  230 ILLTLINPYLLG 241
 
Name Accession Description Interval E-value
CYTB MTH00156
cytochrome b; Provisional
2-93 1.29e-36

cytochrome b; Provisional


Pssm-ID: 214440 [Multi-domain]  Cd Length: 356  Bit Score: 126.05  E-value: 1.29e-36
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00156  150 LVQWIWGGFSVDNATLTRFFTFHFLLPFIILAMVMIHLLFLHQTGSNNPLGLNSNIDKIPFHPYFTFKDLVGFIIMLMLL 229
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00156  230 ILLTLINPYLLG 241
QcrB/PetB COG1290
Cytochrome b subunit of the bc complex [Energy production and conversion];
2-89 1.73e-12

Cytochrome b subunit of the bc complex [Energy production and conversion];


Pssm-ID: 440901 [Multi-domain]  Cd Length: 393  Bit Score: 60.96  E-value: 1.73e-12
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFH-FLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGK----IPFHPLCTCKDLVGFLI 76
Cdd:COG1290   171 LVTWLFGGEFPGDATLNRFFALHvLLLPALLLALVVLHLWLLHRHGHNNPPGPERKKTEkvdgVPFHPYYTVKDGFGFFV 250
                          90
                  ....*....|...
gi 1573074289  77 PLSSLTYISIFYP 89
Cdd:COG1290   251 FLGVFALLAFFFP 263
Cytochrome_b_N cd00284
Cytochrome b (N-terminus)/b6/petB: Cytochrome b is a subunit of cytochrome bc1, an 11-subunit ...
2-48 1.87e-10

Cytochrome b (N-terminus)/b6/petB: Cytochrome b is a subunit of cytochrome bc1, an 11-subunit mitochondrial respiratory enzyme. Cytochrome b spans the mitochondrial membrane with 8 transmembrane helices (A-H) in eukaryotes. In plants and cyanobacteria, cytochrome b6 is analogous to eukaryote cytochrome b, containing two chains: helices A-D are encoded by the petB gene and helices E-H are encoded by the petD gene in these organisms. Cytochrome b/b6 contains two bound hemes and two ubiquinol/ubiquinone binding sites. The C-terminal portion of cytochrome b is described in a separate CD.


Pssm-ID: 238176  Cd Length: 200  Bit Score: 54.30  E-value: 1.87e-10
                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSN 48
Cdd:cd00284   154 LVEWLWGGFSVDNATLTRFFALHFLLPFIIAVIVILHLLFLHEQGSS 200
Cytochrom_B_N_2 pfam13631
Cytochrome b(N-terminal)/b6/petB;
2-76 3.41e-10

Cytochrome b(N-terminal)/b6/petB;


Pssm-ID: 433364  Cd Length: 169  Bit Score: 53.40  E-value: 3.41e-10
                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHF-LMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLI 76
Cdd:pfam13631  75 LVWLLFGGPFPGTATIPRFYALHIlLLPGLILALIVAHLLLVEKHGQFPPPGTEKNVVGVPFWPVFAVKMLLFFLI 150
 
Name Accession Description Interval E-value
CYTB MTH00156
cytochrome b; Provisional
2-93 1.29e-36

cytochrome b; Provisional


Pssm-ID: 214440 [Multi-domain]  Cd Length: 356  Bit Score: 126.05  E-value: 1.29e-36
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00156  150 LVQWIWGGFSVDNATLTRFFTFHFLLPFIILAMVMIHLLFLHQTGSNNPLGLNSNIDKIPFHPYFTFKDLVGFIIMLMLL 229
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00156  230 ILLTLINPYLLG 241
CYTB MTH00131
cytochrome b; Provisional
2-93 4.29e-35

cytochrome b; Provisional


Pssm-ID: 177189 [Multi-domain]  Cd Length: 380  Bit Score: 122.45  E-value: 4.29e-35
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00131  160 LVQWIWGGFSVDNATLTRFFAFHFLFPFVIAAATILHLLFLHETGSNNPLGLNSDADKISFHPYFSYKDLLGFAILLLAL 239
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00131  240 TSLALFSPNLLG 251
CYTB MTH00191
cytochrome b; Provisional
2-93 2.64e-33

cytochrome b; Provisional


Pssm-ID: 177239 [Multi-domain]  Cd Length: 365  Bit Score: 117.71  E-value: 2.64e-33
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00191  157 LVQWLWGGFSVDNATLTRFFTFHFLLPFLIAALSLIHLLFLHETGSNNPLGLNSDSDKIPFHPYFSYKDILGFFILLFLL 236
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00191  237 LFLVLFSPNLLG 248
CYTB MTH00119
cytochrome b; Provisional
2-93 4.42e-33

cytochrome b; Provisional


Pssm-ID: 214425 [Multi-domain]  Cd Length: 380  Bit Score: 117.31  E-value: 4.42e-33
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00119  161 LVEWIWGGFSVDNPTLTRFFALHFLLPFLIAGLTLIHLLFLHETGSNNPLGLNSNTDKIPFHPYFSYKDLLGLTLMLTLL 240
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00119  241 LTLALFSPNLLG 252
CYTB MTH00074
cytochrome b; Provisional
2-93 4.86e-33

cytochrome b; Provisional


Pssm-ID: 177145 [Multi-domain]  Cd Length: 380  Bit Score: 117.09  E-value: 4.86e-33
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00074  161 LVQWIWGGFSVDKATLTRFFAFHFLLPFLIAGASIIHLLFLHETGSNNPTGLNSNPDKVPFHPYFSYKDLLGFLIMLTAL 240
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00074  241 ALLSLFSPNLLG 252
CYTB MTH00016
cytochrome b; Validated
2-93 2.48e-32

cytochrome b; Validated


Pssm-ID: 177102 [Multi-domain]  Cd Length: 378  Bit Score: 115.16  E-value: 2.48e-32
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00016  161 LVQWLWGGFSVDNATLTRFFALHFLLPFVIAALSMIHLLFLHQTGSNNPLGVNSNSDKVPFHPYYTSKDIVGFIVMLFLL 240
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00016  241 LSVVLLWPNILG 252
CYTB MTH00100
cytochrome b; Provisional
2-93 4.23e-32

cytochrome b; Provisional


Pssm-ID: 177162 [Multi-domain]  Cd Length: 379  Bit Score: 114.74  E-value: 4.23e-32
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00100  160 LVEWIWGGFSVDKATLTRFFAFHFILPFIITALAMVHLLFLHETGSNNPSGIPSDSDKIPFHPYYTIKDILGLLLLILTL 239
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00100  240 MLLVLFSPDLLG 251
CYTB MTH00145
cytochrome b; Provisional
2-93 5.04e-32

cytochrome b; Provisional


Pssm-ID: 177203 [Multi-domain]  Cd Length: 379  Bit Score: 114.23  E-value: 5.04e-32
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00145  161 LVEWVWGGFSVGNATLKRFFSLHFLLPFVILGLSVLHLLFLHETGSNNPLGLDSDGDKVPFHPYYTIKDLVGFVVLLFLL 240
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00145  241 VFLVLFFPNLLG 252
CYTB MTH00034
cytochrome b; Validated
2-93 2.30e-30

cytochrome b; Validated


Pssm-ID: 177109 [Multi-domain]  Cd Length: 379  Bit Score: 110.18  E-value: 2.30e-30
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00034  160 IVQWIWGGFSVDNATLTRFFAFHFLFPFIIAALSIIHLLFLHQTGSNNPTGLNSNYDKVPFHTYFTTKDLVGFLILFAAL 239
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00034  240 SSLALLFPTALN 251
CYTB MTH00224
cytochrome b; Provisional
2-92 6.56e-28

cytochrome b; Provisional


Pssm-ID: 164767 [Multi-domain]  Cd Length: 379  Bit Score: 103.46  E-value: 6.56e-28
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00224  161 LVEWIWGGFAVDNATLNRFFSFHFLLPFAIMGATILHIMFLHQTGSNNPIGINADSARIPFHPYYSIKDALGYLIAILLL 240
                          90
                  ....*....|.
gi 1573074289  82 TYISIFYPHTL 92
Cdd:MTH00224  241 SLMVLFEPNLF 251
CYTB MTH00022
cytochrome b; Validated
2-93 1.13e-21

cytochrome b; Validated


Pssm-ID: 164595 [Multi-domain]  Cd Length: 379  Bit Score: 86.68  E-value: 1.13e-21
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00022  159 IVQWVWGGFSVSNATLNRFFSLHFLFPFILAFLVIVHLIYLHVDGSNNPIGLNSSVDKVSFHVYYTSKDWYGIVVLFFLL 238
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00022  239 SFIVYFAPNLLG 250
CYTB MTH00053
cytochrome b; Provisional
2-93 1.96e-19

cytochrome b; Provisional


Pssm-ID: 164624 [Multi-domain]  Cd Length: 381  Bit Score: 80.52  E-value: 1.96e-19
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00053  161 IVRWVWGGFSVSNATLNRFYSLHYLLPFILAGLALVHLIALHEDGSNNPIGVRSDIDKIPFHYYYVLKDLYGAVILLIIL 240
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00053  241 SIIVFLFPYSLG 252
CYTB MTH00033
cytochrome b; Provisional
2-86 1.47e-15

cytochrome b; Provisional


Pssm-ID: 133672 [Multi-domain]  Cd Length: 383  Bit Score: 69.97  E-value: 1.47e-15
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLSSL 81
Cdd:MTH00033  157 IVEWIWGGFSVSNCTLNRFFSLHYLLPFVLVGLVLAHLLTLHEKGSNEPLGLVGLSDRTAFHVYFTIKDILGFLILFGVF 236

                  ....*
gi 1573074289  82 TYISI 86
Cdd:MTH00033  237 VIIGI 241
QcrB/PetB COG1290
Cytochrome b subunit of the bc complex [Energy production and conversion];
2-89 1.73e-12

Cytochrome b subunit of the bc complex [Energy production and conversion];


Pssm-ID: 440901 [Multi-domain]  Cd Length: 393  Bit Score: 60.96  E-value: 1.73e-12
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFH-FLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGK----IPFHPLCTCKDLVGFLI 76
Cdd:COG1290   171 LVTWLFGGEFPGDATLNRFFALHvLLLPALLLALVVLHLWLLHRHGHNNPPGPERKKTEkvdgVPFHPYYTVKDGFGFFV 250
                          90
                  ....*....|...
gi 1573074289  77 PLSSLTYISIFYP 89
Cdd:COG1290   251 FLGVFALLAFFFP 263
CYTB MTH00086
cytochrome b; Provisional
2-93 2.27e-12

cytochrome b; Provisional


Pssm-ID: 177151 [Multi-domain]  Cd Length: 355  Bit Score: 60.72  E-value: 2.27e-12
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLIPLsSL 81
Cdd:MTH00086  149 IVMWIWGGFGVSSATLKFFFVLHFLLPWGLLVLVLFHLIFLHSTGSTSSLYCHGDYDKICFGPEYWNKDAYNIIFWL-VF 227
                          90
                  ....*....|..
gi 1573074289  82 TYISIFYPHTLG 93
Cdd:MTH00086  228 IIFSLFYPFNLG 239
Cytochrome_b_N cd00284
Cytochrome b (N-terminus)/b6/petB: Cytochrome b is a subunit of cytochrome bc1, an 11-subunit ...
2-48 1.87e-10

Cytochrome b (N-terminus)/b6/petB: Cytochrome b is a subunit of cytochrome bc1, an 11-subunit mitochondrial respiratory enzyme. Cytochrome b spans the mitochondrial membrane with 8 transmembrane helices (A-H) in eukaryotes. In plants and cyanobacteria, cytochrome b6 is analogous to eukaryote cytochrome b, containing two chains: helices A-D are encoded by the petB gene and helices E-H are encoded by the petD gene in these organisms. Cytochrome b/b6 contains two bound hemes and two ubiquinol/ubiquinone binding sites. The C-terminal portion of cytochrome b is described in a separate CD.


Pssm-ID: 238176  Cd Length: 200  Bit Score: 54.30  E-value: 1.87e-10
                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSN 48
Cdd:cd00284   154 LVEWLWGGFSVDNATLTRFFALHFLLPFIIAVIVILHLLFLHEQGSS 200
Cytochrom_B_N_2 pfam13631
Cytochrome b(N-terminal)/b6/petB;
2-76 3.41e-10

Cytochrome b(N-terminal)/b6/petB;


Pssm-ID: 433364  Cd Length: 169  Bit Score: 53.40  E-value: 3.41e-10
                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHF-LMPFIISAKVVIHLLFIHQSGSNNALGINGNHGKIPFHPLCTCKDLVGFLI 76
Cdd:pfam13631  75 LVWLLFGGPFPGTATIPRFYALHIlLLPGLILALIVAHLLLVEKHGQFPPPGTEKNVVGVPFWPVFAVKMLLFFLI 150
CYTB MTH00046
cytochrome b; Validated
8-92 9.63e-09

cytochrome b; Validated


Pssm-ID: 177121 [Multi-domain]  Cd Length: 355  Bit Score: 50.37  E-value: 9.63e-09
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1573074289   8 GGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSGSNNALGINGNHGK-IPFHPLCTCKDLVGFLIPLSSLTYISI 86
Cdd:MTH00046  157 GGFSVTGVTLVRVFSVHICLGFVILGLMVVHLFYLHKSGSSNPLFSSNGYSDvVYFHSYFTVKDLFLFMVVCSLLVFWLF 236

                  ....*.
gi 1573074289  87 FYPHTL 92
Cdd:MTH00046  237 VSPDLV 242
Cytochrome_B pfam00033
Cytochrome b/b6/petB;
2-46 5.62e-08

Cytochrome b/b6/petB;


Pssm-ID: 306530  Cd Length: 189  Bit Score: 47.76  E-value: 5.62e-08
                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1573074289   2 LVQWFWGGFAVDNPTSAQSLTFHFLMPFIISAKVVIHLLFIHQSG 46
Cdd:pfam00033 145 LVEWIWGSFSVDQATLTRFFSLHFLLPFILAILMLLHLLFLHETG 189
 
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