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Protein

Carbonic anhydrase 6

Gene

CA6

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Reversible hydration of carbon dioxide. Its role in saliva is unknown.

Catalytic activityi

H2CO3 = CO2 + H2O.

Cofactori

Zn2+By similarity

Enzyme regulationi

Inhibited by coumarins, sulfonamide derivatives such as acetazolamide (AZA), saccharin and Foscarnet (phosphonoformate trisodium salt).4 Publications

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Active sitei85 – 851Proton acceptorBy similarity
Metal bindingi111 – 1111Zinc; catalytic
Metal bindingi113 – 1131Zinc; catalytic
Metal bindingi138 – 1381Zinc; catalytic
Active sitei146 – 1461By similarity

GO - Molecular functioni

  1. carbonate dehydratase activity Source: Reactome
  2. zinc ion binding Source: InterPro

GO - Biological processi

  1. bicarbonate transport Source: Reactome
  2. detection of chemical stimulus involved in sensory perception of bitter taste Source: UniProtKB
  3. one-carbon metabolic process Source: InterPro
  4. small molecule metabolic process Source: Reactome
Complete GO annotation...

Keywords - Molecular functioni

Lyase

Keywords - Ligandi

Metal-binding, Zinc

Enzyme and pathway databases

BRENDAi4.2.1.1. 2681.
ReactomeiREACT_121123. Reversible hydration of carbon dioxide.

Names & Taxonomyi

Protein namesi
Recommended name:
Carbonic anhydrase 6 (EC:4.2.1.1)
Alternative name(s):
Carbonate dehydratase VI
Carbonic anhydrase VI
Short name:
CA-VI
Salivary carbonic anhydrase
Secreted carbonic anhydrase
Gene namesi
Name:CA6
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
ProteomesiUP000005640: Chromosome 1

Organism-specific databases

HGNCiHGNC:1380. CA6.

Subcellular locationi

GO - Cellular componenti

  1. cytoplasm Source: Ensembl
  2. extracellular region Source: Reactome
  3. extracellular space Source: UniProtKB
  4. extracellular vesicular exosome Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Organism-specific databases

PharmGKBiPA25995.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Signal peptidei1 – 1717Sequence AnalysisAdd
BLAST
Chaini18 – 308291Carbonic anhydrase 6PRO_0000004241Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi42 ↔ 224Sequence Analysis
Glycosylationi67 – 671N-linked (GlcNAc...)Sequence Analysis
Glycosylationi256 – 2561N-linked (GlcNAc...)Sequence Analysis

Keywords - PTMi

Disulfide bond, Glycoprotein

Proteomic databases

PaxDbiP23280.
PRIDEiP23280.

Expressioni

Tissue specificityi

Major constituent of saliva.

Gene expression databases

BgeeiP23280.
CleanExiHS_CA6.
ExpressionAtlasiP23280. baseline and differential.
GenevestigatoriP23280.

Organism-specific databases

HPAiHPA028550.
HPA028692.

Interactioni

Protein-protein interaction databases

BioGridi107220. 3 interactions.
STRINGi9606.ENSP00000366662.

Structurei

Secondary structure

1
308
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Helixi35 – 384Combined sources
Helixi40 – 434Combined sources
Beta strandi44 – 463Combined sources
Helixi54 – 563Combined sources
Beta strandi68 – 703Combined sources
Beta strandi72 – 8211Combined sources
Beta strandi87 – 904Combined sources
Beta strandi96 – 983Combined sources
Beta strandi104 – 11411Combined sources
Beta strandi125 – 1284Combined sources
Beta strandi134 – 14310Combined sources
Beta strandi146 – 1483Combined sources
Helixi149 – 1524Combined sources
Beta strandi159 – 1679Combined sources
Helixi175 – 1773Combined sources
Helixi178 – 1836Combined sources
Helixi184 – 1874Combined sources
Beta strandi193 – 1997Combined sources
Helixi201 – 2044Combined sources
Beta strandi212 – 2176Combined sources
Beta strandi228 – 2358Combined sources
Helixi241 – 2499Combined sources
Beta strandi256 – 2583Combined sources
Beta strandi275 – 2773Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
3FE4X-ray1.90A/B21-290[»]
ProteinModelPortaliP23280.
SMRiP23280. Positions 33-280.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP23280.

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni220 – 2212Substrate bindingBy similarity

Sequence similaritiesi

Belongs to the alpha-carbonic anhydrase family.Curated

Keywords - Domaini

Signal

Phylogenomic databases

eggNOGiCOG3338.
GeneTreeiENSGT00760000118915.
HOGENOMiHOG000112637.
HOVERGENiHBG002837.
InParanoidiP23280.
KOiK01672.
OMAiPNQGKGH.
PhylomeDBiP23280.
TreeFamiTF316425.

Family and domain databases

Gene3Di3.10.200.10. 1 hit.
InterProiIPR001148. Carbonic_anhydrase_a.
IPR023561. Carbonic_anhydrase_a-class.
IPR018338. Carbonic_anhydrase_a-class_CS.
IPR018428. Carbonic_anhydrase_CA6.
[Graphical view]
PANTHERiPTHR18952. PTHR18952. 1 hit.
PTHR18952:SF17. PTHR18952:SF17. 1 hit.
PfamiPF00194. Carb_anhydrase. 1 hit.
[Graphical view]
SMARTiSM01057. Carb_anhydrase. 1 hit.
[Graphical view]
SUPFAMiSSF51069. SSF51069. 1 hit.
PROSITEiPS00162. ALPHA_CA_1. 1 hit.
PS51144. ALPHA_CA_2. 1 hit.
[Graphical view]

Sequences (3)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 3 isoformsi produced by alternative splicing. Align

Isoform 1 (identifier: P23280-1) [UniParc]FASTAAdd to Basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MRALVLLLSL FLLGGQAQHV SDWTYSEGAL DEAHWPQHYP ACGGQRQSPI
60 70 80 90 100
NLQRTKVRYN PSLKGLNMTG YETQAGEFPM VNNGHTVQIS LPSTMRMTVA
110 120 130 140 150
DGTVYIAQQM HFHWGGASSE ISGSEHTVDG IRHVIEIHIV HYNSKYKSYD
160 170 180 190 200
IAQDAPDGLA VLAAFVEVKN YPENTYYSNF ISHLANIKYP GQRTTLTGLD
210 220 230 240 250
VQDMLPRNLQ HYYTYHGSLT TPPCTENVHW FVLADFVKLS RTQVWKLENS
260 270 280 290 300
LLDHRNKTIH NDYRRTQPLN HRVVESNFPN QEYTLGSEFQ FYLHKIEEIL

DYLRRALN
Length:308
Mass (Da):35,367
Last modified:October 17, 2006 - v3
Checksum:i6EBFF15085E7112D
GO
Isoform 2 (identifier: P23280-2) [UniParc]FASTAAdd to Basket

The sequence of this isoform differs from the canonical sequence as follows:
     282-308: EYTLGSEFQFYLHKIEEILDYLRRALN → GKGHGGHRGRSQNPRVQPTSTRHPLALGSLEA

Note: No experimental confirmation available.

Show »
Length:313
Mass (Da):35,365
Checksum:i1CF67B5ED1BD9384
GO
Isoform 3 (identifier: P23280-3) [UniParc]FASTAAdd to Basket

The sequence of this isoform differs from the canonical sequence as follows:
     27-86: Missing.

Note: No experimental confirmation available.

Show »
Length:248
Mass (Da):28,687
Checksum:i39A6223C958A3029
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti103 – 1031T → I in AAA51892. (PubMed:1899030)Curated
Sequence conflicti103 – 1031T → I in BAD89434. (PubMed:16710414)Curated
Sequence conflicti148 – 1481S → T in AAA51892. (PubMed:1899030)Curated
Sequence conflicti148 – 1481S → T in AAF22565. 1 PublicationCurated
Sequence conflicti148 – 1481S → T in BAD89434. (PubMed:16710414)Curated
Sequence conflicti270 – 2701N → K in AAA51892. (PubMed:1899030)Curated
Sequence conflicti270 – 2701N → K in AAF22565. 1 PublicationCurated
Sequence conflicti270 – 2701N → K in BAD89434. (PubMed:16710414)Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti37 – 371Q → L.
Corresponds to variant rs34265054 [ dbSNP | Ensembl ].
VAR_033712
Natural varianti55 – 551T → M.
Corresponds to variant rs2274327 [ dbSNP | Ensembl ].
VAR_028268
Natural varianti58 – 581R → W.
Corresponds to variant rs58800854 [ dbSNP | Ensembl ].
VAR_061093
Natural varianti68 – 681M → L.
Corresponds to variant rs2274328 [ dbSNP | Ensembl ].
VAR_028269
Natural varianti70 – 701G → A.
Corresponds to variant rs2274329 [ dbSNP | Ensembl ].
VAR_028270
Natural varianti90 – 901S → G.3 Publications
Corresponds to variant rs2274333 [ dbSNP | Ensembl ].
VAR_028271

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei27 – 8660Missing in isoform 3. 1 PublicationVSP_046668Add
BLAST
Alternative sequencei282 – 30827EYTLG…RRALN → GKGHGGHRGRSQNPRVQPTS TRHPLALGSLEA in isoform 2. 1 PublicationVSP_045435Add
BLAST

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M57892 mRNA. Translation: AAA51892.1.
AF128418
, AF128411, AF128412, AF128413, AF128414, AF128415, AF128416, AF128417 Genomic DNA. Translation: AAF22565.1.
AB102863 mRNA. Translation: BAD89397.1.
AB103091 mRNA. Translation: BAD89434.1.
AL139415 Genomic DNA. Translation: CAC42429.1.
CCDSiCCDS30578.1. [P23280-1]
CCDS57970.1. [P23280-2]
CCDS57971.1. [P23280-3]
PIRiA37917. CRHU6.
RefSeqiNP_001206.2. NM_001215.3. [P23280-1]
NP_001257429.1. NM_001270500.1. [P23280-2]
NP_001257430.1. NM_001270501.1. [P23280-3]
UniGeneiHs.100322.

Genome annotation databases

EnsembliENST00000377436; ENSP00000366654; ENSG00000131686. [P23280-2]
ENST00000377442; ENSP00000366661; ENSG00000131686. [P23280-3]
ENST00000377443; ENSP00000366662; ENSG00000131686. [P23280-1]
GeneIDi765.
KEGGihsa:765.
UCSCiuc001apm.4. human. [P23280-1]
uc031plc.1. human.

Polymorphism databases

DMDMi116241278.

Keywords - Coding sequence diversityi

Alternative splicing, Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M57892 mRNA. Translation: AAA51892.1.
AF128418
, AF128411, AF128412, AF128413, AF128414, AF128415, AF128416, AF128417 Genomic DNA. Translation: AAF22565.1.
AB102863 mRNA. Translation: BAD89397.1.
AB103091 mRNA. Translation: BAD89434.1.
AL139415 Genomic DNA. Translation: CAC42429.1.
CCDSiCCDS30578.1. [P23280-1]
CCDS57970.1. [P23280-2]
CCDS57971.1. [P23280-3]
PIRiA37917. CRHU6.
RefSeqiNP_001206.2. NM_001215.3. [P23280-1]
NP_001257429.1. NM_001270500.1. [P23280-2]
NP_001257430.1. NM_001270501.1. [P23280-3]
UniGeneiHs.100322.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
3FE4X-ray1.90A/B21-290[»]
ProteinModelPortaliP23280.
SMRiP23280. Positions 33-280.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi107220. 3 interactions.
STRINGi9606.ENSP00000366662.

Chemistry

BindingDBiP23280.
ChEMBLiCHEMBL3025.
DrugBankiDB06795. Mafenide.
DB00909. Zonisamide.

Polymorphism databases

DMDMi116241278.

Proteomic databases

PaxDbiP23280.
PRIDEiP23280.

Protocols and materials databases

DNASUi765.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000377436; ENSP00000366654; ENSG00000131686. [P23280-2]
ENST00000377442; ENSP00000366661; ENSG00000131686. [P23280-3]
ENST00000377443; ENSP00000366662; ENSG00000131686. [P23280-1]
GeneIDi765.
KEGGihsa:765.
UCSCiuc001apm.4. human. [P23280-1]
uc031plc.1. human.

Organism-specific databases

CTDi765.
GeneCardsiGC01P009005.
H-InvDBHIX0028508.
HIX0116265.
HGNCiHGNC:1380. CA6.
HPAiHPA028550.
HPA028692.
MIMi114780. gene.
neXtProtiNX_P23280.
PharmGKBiPA25995.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiCOG3338.
GeneTreeiENSGT00760000118915.
HOGENOMiHOG000112637.
HOVERGENiHBG002837.
InParanoidiP23280.
KOiK01672.
OMAiPNQGKGH.
PhylomeDBiP23280.
TreeFamiTF316425.

Enzyme and pathway databases

BRENDAi4.2.1.1. 2681.
ReactomeiREACT_121123. Reversible hydration of carbon dioxide.

Miscellaneous databases

EvolutionaryTraceiP23280.
GeneWikiiCarbonic_anhydrase_VI.
GenomeRNAii765.
NextBioi3092.
PROiP23280.
SOURCEiSearch...

Gene expression databases

BgeeiP23280.
CleanExiHS_CA6.
ExpressionAtlasiP23280. baseline and differential.
GenevestigatoriP23280.

Family and domain databases

Gene3Di3.10.200.10. 1 hit.
InterProiIPR001148. Carbonic_anhydrase_a.
IPR023561. Carbonic_anhydrase_a-class.
IPR018338. Carbonic_anhydrase_a-class_CS.
IPR018428. Carbonic_anhydrase_CA6.
[Graphical view]
PANTHERiPTHR18952. PTHR18952. 1 hit.
PTHR18952:SF17. PTHR18952:SF17. 1 hit.
PfamiPF00194. Carb_anhydrase. 1 hit.
[Graphical view]
SMARTiSM01057. Carb_anhydrase. 1 hit.
[Graphical view]
SUPFAMiSSF51069. SSF51069. 1 hit.
PROSITEiPS00162. ALPHA_CA_1. 1 hit.
PS51144. ALPHA_CA_2. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Human secreted carbonic anhydrase: cDNA cloning, nucleotide sequence, and hybridization histochemistry."
    Aldred P., Fu P., Barrett G., Penschow J.D., Wright R., Coghlan J.P., Fernley R.T.
    Biochemistry 30:569-575(1991) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1), VARIANT GLY-90.
  2. Grubb D.J.
    Submitted (FEB-1999) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], VARIANT GLY-90.
  3. "CA6 mRNA, nirs splice variant 1."
    Tabata Y., Hayashi A., Sameshima E., Iida K., Mitsuyama M., Kanai S., Furuya T., Saito T.
    Submitted (FEB-2003) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 2 AND 3), VARIANT GLY-90.
  4. "The DNA sequence and biological annotation of human chromosome 1."
    Gregory S.G., Barlow K.F., McLay K.E., Kaul R., Swarbreck D., Dunham A., Scott C.E., Howe K.L., Woodfine K., Spencer C.C.A., Jones M.C., Gillson C., Searle S., Zhou Y., Kokocinski F., McDonald L., Evans R., Phillips K.
    , Atkinson A., Cooper R., Jones C., Hall R.E., Andrews T.D., Lloyd C., Ainscough R., Almeida J.P., Ambrose K.D., Anderson F., Andrew R.W., Ashwell R.I.S., Aubin K., Babbage A.K., Bagguley C.L., Bailey J., Beasley H., Bethel G., Bird C.P., Bray-Allen S., Brown J.Y., Brown A.J., Buckley D., Burton J., Bye J., Carder C., Chapman J.C., Clark S.Y., Clarke G., Clee C., Cobley V., Collier R.E., Corby N., Coville G.J., Davies J., Deadman R., Dunn M., Earthrowl M., Ellington A.G., Errington H., Frankish A., Frankland J., French L., Garner P., Garnett J., Gay L., Ghori M.R.J., Gibson R., Gilby L.M., Gillett W., Glithero R.J., Grafham D.V., Griffiths C., Griffiths-Jones S., Grocock R., Hammond S., Harrison E.S.I., Hart E., Haugen E., Heath P.D., Holmes S., Holt K., Howden P.J., Hunt A.R., Hunt S.E., Hunter G., Isherwood J., James R., Johnson C., Johnson D., Joy A., Kay M., Kershaw J.K., Kibukawa M., Kimberley A.M., King A., Knights A.J., Lad H., Laird G., Lawlor S., Leongamornlert D.A., Lloyd D.M., Loveland J., Lovell J., Lush M.J., Lyne R., Martin S., Mashreghi-Mohammadi M., Matthews L., Matthews N.S.W., McLaren S., Milne S., Mistry S., Moore M.J.F., Nickerson T., O'Dell C.N., Oliver K., Palmeiri A., Palmer S.A., Parker A., Patel D., Pearce A.V., Peck A.I., Pelan S., Phelps K., Phillimore B.J., Plumb R., Rajan J., Raymond C., Rouse G., Saenphimmachak C., Sehra H.K., Sheridan E., Shownkeen R., Sims S., Skuce C.D., Smith M., Steward C., Subramanian S., Sycamore N., Tracey A., Tromans A., Van Helmond Z., Wall M., Wallis J.M., White S., Whitehead S.L., Wilkinson J.E., Willey D.L., Williams H., Wilming L., Wray P.W., Wu Z., Coulson A., Vaudin M., Sulston J.E., Durbin R.M., Hubbard T., Wooster R., Dunham I., Carter N.P., McVean G., Ross M.T., Harrow J., Olson M.V., Beck S., Rogers J., Bentley D.R.
    Nature 441:315-321(2006) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  5. "Saccharin inhibits carbonic anhydrases: possible explanation for its unpleasant metallic aftertaste."
    Koehler K., Hillebrecht A., Schulze Wischeler J., Innocenti A., Heine A., Supuran C.T., Klebe G.
    Angew. Chem. Int. Ed. Engl. 46:7697-7699(2007) [PubMed] [Europe PMC] [Abstract]
    Cited for: ENZYME REGULATION.
  6. "Phosph(on)ate as a zinc-binding group in metalloenzyme inhibitors: X-ray crystal structure of the antiviral drug foscarnet complexed to human carbonic anhydrase I."
    Temperini C., Innocenti A., Guerri A., Scozzafava A., Rusconi S., Supuran C.T.
    Bioorg. Med. Chem. Lett. 17:2210-2215(2007) [PubMed] [Europe PMC] [Abstract]
    Cited for: ENZYME REGULATION.
  7. "A thiabendazole sulfonamide shows potent inhibitory activity against mammalian and nematode alpha-carbonic anhydrases."
    Crocetti L., Maresca A., Temperini C., Hall R.A., Scozzafava A., Muehlschlegel F.A., Supuran C.T.
    Bioorg. Med. Chem. Lett. 19:1371-1375(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: ENZYME REGULATION.
  8. "Non-zinc mediated inhibition of carbonic anhydrases: coumarins are a new class of suicide inhibitors."
    Maresca A., Temperini C., Vu H., Pham N.B., Poulsen S.-A., Scozzafava A., Quinn R.J., Supuran C.T.
    J. Am. Chem. Soc. 131:3057-3062(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: ENZYME REGULATION.
  9. "Crystal structure of human erythrocyte carbonic anhydrase C. VI. The three-dimensional structure at high resolution in relation to other mammalian carbonic anhydrases."
    Kannan K.K., Liljas A., Waara I., Bergsten P.C., Loevgren S., Strandberg B., Bengtsson U., Carlbom U., Fridborg K., Jaerup L., Petef M.
    Cold Spring Harb. Symp. Quant. Biol. 36:221-231(1972) [PubMed] [Europe PMC] [Abstract]
    Cited for: X-RAY CRYSTALLOGRAPHY (1.90 ANGSTROMS) OF 21-290 IN COMPLEX WITH MAGNESIUM ION.

Entry informationi

Entry nameiCAH6_HUMAN
AccessioniPrimary (citable) accession number: P23280
Secondary accession number(s): E7EMQ1
, Q5FBW3, Q5FC00, Q96QX8, Q9UF03
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1991
Last sequence update: October 17, 2006
Last modified: February 4, 2015
This is version 144 of the entry and version 3 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Human chromosome 1
    Human chromosome 1: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  6. SIMILARITY comments
    Index of protein domains and families

External Data

Dasty 3

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into Uniref entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.