Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.
Protein

Cobra venom factor

Gene
N/A
Organism
Naja kaouthia (Monocled cobra) (Naja siamensis)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Complement-activating protein in cobra venom. It is a structural and functional analog of complement component C3b, the activated form of C3. It binds factor B (CFB), which is subsequently cleaved by factor D (CFD) to form the bimolecular complex CVF/Bb. CVF/Bb is a C3/C5 convertase that cleaves both complement components C3 and C5. Structurally, it resembles the C3b degradation product C3c, which is not able to form a C3/C5 convertase. Unlike C3b/Bb, CVF/Bb is a stable complex and completely resistant to the actions of complement regulatory factors H (CFH) and I (CFI). Therefore, CVF continuously activates complement resulting in the depletion of complement activity.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi516Magnesium; via carbonyl oxygen1
Metal bindingi539Magnesium1
Metal bindingi540Magnesium; via carbonyl oxygen1
Metal bindingi542Magnesium1

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Complement system impairing toxin, Toxin

Keywords - Biological processi

Inflammatory response

Keywords - Ligandi

Metal-binding

Protein family/group databases

MEROPSiI39.950.

Names & Taxonomyi

Protein namesi
Recommended name:
Cobra venom factor
Short name:
CVF
Short name:
CVFk
Alternative name(s):
Complement C3 homolog
Cleaved into the following 3 chains:
OrganismiNaja kaouthia (Monocled cobra) (Naja siamensis)
Taxonomic identifieri8649 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiLepidosauriaSquamataBifurcataUnidentataEpisquamataToxicoferaSerpentesColubroideaElapidaeElapinaeNaja

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Secreted

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 22By similarityAdd BLAST22
ChainiPRO_000000592823 – 1642Cobra venom factorAdd BLAST1620
ChainiPRO_000000592923 – 649Cobra venom factor alpha chainAdd BLAST627
PropeptideiPRO_0000423372650 – 732Add BLAST83
ChainiPRO_0000005930733 – 984Cobra venom factor gamma chainAdd BLAST252
PropeptideiPRO_0000423373985 – 1263Add BLAST279
ChainiPRO_00000059311264 – 1642Cobra venom factor beta chainAdd BLAST379

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Glycosylationi153N-linked (GlcNAc...)Sequence analysis1
Glycosylationi158N-linked (GlcNAc...)Sequence analysis1
Glycosylationi209N-linked (GlcNAc...)2 Publications1
Disulfide bondi544 ↔ 801Interchain (between alpha and gamma chains)
Disulfide bondi609 ↔ 644
Disulfide bondi677 ↔ 704By similarity
Disulfide bondi678 ↔ 711By similarity
Disulfide bondi691 ↔ 712By similarity
Disulfide bondi857 ↔ 1492Interchain (between gamma and beta chains)
Cross-linki993 ↔ 996Isoglutamyl cysteine thioester (Cys-Gln)By similarity
Disulfide bondi1340 ↔ 1468
Glycosylationi1346N-linked (GlcNAc...)2 Publications1
Disulfide bondi1368 ↔ 1437
Disulfide bondi1485 ↔ 1490
Disulfide bondi1497 ↔ 1569
Disulfide bondi1516 ↔ 1640
Disulfide bondi1616 ↔ 1625

Post-translational modificationi

First processed by the removal of 4 Arg residues by furin-type protease, forming two chains, alpha and gamma/beta precursor, linked by a disulfide bond. Probably, the cobrin cleaves the C3a-like domain and then the C3d-like domain, generating the mature cobra venom factor (CVF). This mature CVF is composed of three chains: alpha, gamma and beta.
Contains 3 N-linked oligosaccharide chains, two in the alpha-chain and one in the beta-chain. Glycosylation is not required for the biological activity. However, it contributes to the immunogenicity of CVF. The carbohydrate content is 7.4. The major oligosaccharide is a symmetric fucosylated biantennary complex-type chain with an unusual alpha-galactosylated Le(x) structure at its non-reducing end.3 Publications

Keywords - PTMi

Cleavage on pair of basic residues, Disulfide bond, Glycoprotein, Thioester bond

Proteomic databases

TopDownProteomicsiQ91132.

PTM databases

UniCarbKBiQ91132.

Expressioni

Tissue specificityi

Expressed by the venom gland.

Interactioni

Subunit structurei

Heterotrimer of alpha, beta and gamma chains; disulfide-linked. Is active with factor B in the presence of factor D.3 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
C5P010312EBI-7081824,EBI-8558308From a different organism.

Protein-protein interaction databases

IntActiQ91132. 3 interactors.
MINTiMINT-7906427.

Structurei

Secondary structure

11642
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi24 – 35Combined sources12
Beta strandi42 – 47Combined sources6
Beta strandi52 – 61Combined sources10
Beta strandi66 – 75Combined sources10
Helixi77 – 79Combined sources3
Beta strandi81 – 83Combined sources3
Helixi91 – 93Combined sources3
Beta strandi103 – 110Combined sources8
Beta strandi113 – 122Combined sources10
Beta strandi128 – 133Combined sources6
Beta strandi135 – 137Combined sources3
Beta strandi145 – 150Combined sources6
Beta strandi161 – 166Combined sources6
Beta strandi172 – 179Combined sources8
Beta strandi195 – 203Combined sources9
Beta strandi210 – 216Combined sources7
Beta strandi223 – 236Combined sources14
Beta strandi243 – 251Combined sources9
Beta strandi259 – 269Combined sources11
Beta strandi272 – 275Combined sources4
Helixi277 – 279Combined sources3
Beta strandi281 – 286Combined sources6
Beta strandi289 – 294Combined sources6
Helixi296 – 302Combined sources7
Helixi306 – 309Combined sources4
Beta strandi313 – 322Combined sources10
Beta strandi328 – 342Combined sources15
Beta strandi344 – 346Combined sources3
Beta strandi352 – 354Combined sources3
Beta strandi360 – 367Combined sources8
Beta strandi378 – 381Combined sources4
Helixi382 – 384Combined sources3
Beta strandi386 – 389Combined sources4
Beta strandi394 – 400Combined sources7
Beta strandi407 – 415Combined sources9
Beta strandi418 – 420Combined sources3
Helixi422 – 424Combined sources3
Beta strandi427 – 434Combined sources8
Helixi438 – 440Combined sources3
Beta strandi444 – 449Combined sources6
Beta strandi459 – 468Combined sources10
Helixi470 – 474Combined sources5
Beta strandi478 – 485Combined sources8
Beta strandi488 – 496Combined sources9
Beta strandi502 – 509Combined sources8
Helixi512 – 514Combined sources3
Beta strandi516 – 526Combined sources11
Turni527 – 529Combined sources3
Beta strandi530 – 539Combined sources10
Beta strandi548 – 551Combined sources4
Beta strandi562 – 570Combined sources9
Beta strandi574 – 581Combined sources8
Helixi582 – 587Combined sources6
Helixi589 – 591Combined sources3
Helixi595 – 604Combined sources10
Beta strandi610 – 612Combined sources3
Helixi617 – 623Combined sources7
Beta strandi626 – 630Combined sources5
Helixi742 – 744Combined sources3
Beta strandi753 – 755Combined sources3
Beta strandi759 – 761Combined sources3
Beta strandi772 – 779Combined sources8
Beta strandi784 – 795Combined sources12
Turni796 – 798Combined sources3
Beta strandi799 – 802Combined sources4
Beta strandi806 – 810Combined sources5
Beta strandi813 – 818Combined sources6
Beta strandi830 – 838Combined sources9
Beta strandi840 – 842Combined sources3
Beta strandi844 – 850Combined sources7
Beta strandi856 – 859Combined sources4
Beta strandi862 – 864Combined sources3
Beta strandi866 – 872Combined sources7
Beta strandi876 – 886Combined sources11
Beta strandi888 – 900Combined sources13
Beta strandi906 – 916Combined sources11
Beta strandi918 – 930Combined sources13
Helixi932 – 935Combined sources4
Beta strandi937 – 945Combined sources9
Beta strandi959 – 967Combined sources9
Beta strandi1274 – 1280Combined sources7
Beta strandi1282 – 1286Combined sources5
Beta strandi1288 – 1293Combined sources6
Helixi1294 – 1296Combined sources3
Beta strandi1301 – 1307Combined sources7
Beta strandi1311 – 1318Combined sources8
Beta strandi1321 – 1331Combined sources11
Beta strandi1342 – 1351Combined sources10
Beta strandi1363 – 1371Combined sources9
Beta strandi1373 – 1375Combined sources3
Beta strandi1377 – 1385Combined sources9
Beta strandi1390 – 1393Combined sources4
Helixi1394 – 1401Combined sources8
Beta strandi1406 – 1408Combined sources3
Beta strandi1417 – 1419Combined sources3
Beta strandi1421 – 1430Combined sources10
Beta strandi1432 – 1434Combined sources3
Beta strandi1436 – 1444Combined sources9
Beta strandi1454 – 1460Combined sources7
Beta strandi1469 – 1473Combined sources5
Beta strandi1474 – 1476Combined sources3
Beta strandi1483 – 1486Combined sources4
Beta strandi1489 – 1492Combined sources4
Helixi1508 – 1515Combined sources8
Beta strandi1522 – 1534Combined sources13
Beta strandi1537 – 1549Combined sources13
Helixi1556 – 1558Combined sources3
Beta strandi1561 – 1566Combined sources6
Helixi1567 – 1569Combined sources3
Helixi1570 – 1573Combined sources4
Beta strandi1580 – 1585Combined sources6
Helixi1587 – 1589Combined sources3
Beta strandi1596 – 1600Combined sources5
Beta strandi1602 – 1604Combined sources3
Beta strandi1606 – 1610Combined sources5
Helixi1614 – 1617Combined sources4
Turni1619 – 1621Combined sources3
Helixi1622 – 1638Combined sources17

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
3FRPX-ray2.61A23-649[»]
B1264-1642[»]
G733-984[»]
3HRZX-ray2.20A23-649[»]
B733-984[»]
C1264-1642[»]
3HS0X-ray3.00A/F23-649[»]
B/G733-984[»]
C/H1264-1642[»]
3PRXX-ray4.30B/D1-1642[»]
3PVMX-ray4.30B/D1-1642[»]
ProteinModelPortaliQ91132.
SMRiQ91132.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ91132.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini677 – 712Anaphylatoxin-likePROSITE-ProRule annotationAdd BLAST36
Domaini1497 – 1640NTRPROSITE-ProRule annotationAdd BLAST144

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni654 – 732C3a-like domainBy similarityAdd BLAST79
Regioni736 – 747Factor B binding siteBy similarityAdd BLAST12
Regioni985 – 1263C3d-like domainBy similarityAdd BLAST279
Regioni1190 – 1253Factor H binding siteBy similarityAdd BLAST64

Compositional bias

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Compositional biasi650 – 653Poly-Arg4

Sequence similaritiesi

Belongs to the venom complement C3 homolog family.Curated
Contains 1 anaphylatoxin-like domain.PROSITE-ProRule annotation
Contains 1 NTR domain.PROSITE-ProRule annotation

Keywords - Domaini

Signal

Phylogenomic databases

HOVERGENiHBG005110.

Family and domain databases

Gene3Di1.20.91.20. 1 hit.
1.50.10.20. 1 hit.
2.60.40.690. 1 hit.
InterProiIPR009048. A-macroglobulin_rcpt-bd.
IPR011626. A2M_comp.
IPR002890. A2M_N.
IPR011625. A2M_N_2.
IPR000020. Anaphylatoxin/fibulin.
IPR018081. Anaphylatoxin_comp_syst.
IPR001840. Anaphylatoxn_comp_syst_dom.
IPR001599. Macroglobln_a2.
IPR019742. MacrogloblnA2_CS.
IPR019565. MacrogloblnA2_thiol-ester-bond.
IPR001134. Netrin_domain.
IPR018933. Netrin_module_non-TIMP.
IPR008930. Terpenoid_cyclase/PrenylTrfase.
IPR008993. TIMP-like_OB-fold.
[Graphical view]
PfamiPF00207. A2M. 1 hit.
PF07678. A2M_comp. 1 hit.
PF01835. A2M_N. 1 hit.
PF07703. A2M_N_2. 1 hit.
PF07677. A2M_recep. 1 hit.
PF01821. ANATO. 1 hit.
PF01759. NTR. 1 hit.
PF10569. Thiol-ester_cl. 1 hit.
[Graphical view]
PRINTSiPR00004. ANAPHYLATOXN.
SMARTiSM01360. A2M. 1 hit.
SM01359. A2M_N_2. 1 hit.
SM01361. A2M_recep. 1 hit.
SM00104. ANATO. 1 hit.
SM00643. C345C. 1 hit.
[Graphical view]
SUPFAMiSSF47686. SSF47686. 1 hit.
SSF48239. SSF48239. 1 hit.
SSF49410. SSF49410. 1 hit.
SSF50242. SSF50242. 1 hit.
PROSITEiPS00477. ALPHA_2_MACROGLOBULIN. 1 hit.
PS01178. ANAPHYLATOXIN_2. 1 hit.
PS50189. NTR. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

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

Q91132-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MERMALYLVA ALLIGFPGSS HGALYTLITP AVLRTDTEEQ ILVEAHGDST
60 70 80 90 100
PKQLDIFVHD FPRKQKTLFQ TRVDMNPAGG MLVTPTIEIP AKEVSTDSRQ
110 120 130 140 150
NQYVVVQVTG PQVRLEKVVL LSYQSSFLFI QTDKGIYTPG SPVLYRVFSM
160 170 180 190 200
DHNTSKMNKT VIVEFQTPEG ILVSSNSVDL NFFWPYNLPD LVSLGTWRIV
210 220 230 240 250
AKYEHSPENY TAYFDVRKYV LPSFEVRLQP SEKFFYIDGN ENFHVSITAR
260 270 280 290 300
YLYGEEVEGV AFVLFGVKID DAKKSIPDSL TRIPIIDGDG KATLKRDTFR
310 320 330 340 350
SRFPNLNELV GHTLYASVTV MTESGSDMVV TEQSGIHIVA SPYQIHFTKT
360 370 380 390 400
PKYFKPGMPY ELTVYVTNPD GSPAAHVPVV SEAFHSMGTT LSDGTAKLIL
410 420 430 440 450
NIPLNAQSLP ITVRTNHGDL PRERQATKSM TAIAYQTQGG SGNYLHVAIT
460 470 480 490 500
STEIKPGDNL PVNFNVKGNA NSLKQIKYFT YLILNKGKIF KVGRQPRRDG
510 520 530 540 550
QNLVTMNLHI TPDLIPSFRF VAYYQVGNNE IVADSVWVDV KDTCMGTLVV
560 570 580 590 600
KGDNLIQMPG AAMKIKLEGD PGARVGLVAV DKAVYVLNDK YKISQAKIWD
610 620 630 640 650
TIEKSDFGCT AGSGQNNLGV FEDAGLALTT STNLNTKQRS AAKCPQPANR
660 670 680 690 700
RRRSSVLLLD SNASKAAEFQ DQDLRKCCED VMHENPMGYT CEKRAKYIQE
710 720 730 740 750
GDACKAAFLE CCRYIKGVRD ENQRESELFL ARDDNEDGFI ADSDIISRSD
760 770 780 790 800
FPKSWLWLTK DLTEEPNSQG ISSKTMSFYL RDSITTWVVL AVSFTPTKGI
810 820 830 840 850
CVAEPYEIRV MKVFFIDLQM PYSVVKNEQV EIRAILHNYV NEDIYVRVEL
860 870 880 890 900
LYNPAFCSAS TKGQRYRQQF PIKALSSRAV PFVIVPLEQG LHDVEIKASV
910 920 930 940 950
QEALWSDGVR KKLKVVPEGV QKSIVTIVKL DPRAKGVGGT QLEVIKARKL
960 970 980 990 1000
DDRVPDTEIE TKIIIQGDPV AQIIENSIDG SKLNHLIITP SGCGEQNMIR
1010 1020 1030 1040 1050
MAAPVIATYY LDTTEQWETL GINRRTEAVN QIVTGYAQQM VYKKADHSYA
1060 1070 1080 1090 1100
AFTNRASSSW LTAYVVKVFA MAAKMVAGIS HEIICGGVRW LILNRQQPDG
1110 1120 1130 1140 1150
AFKENAPVLS GTMQGGIQGA EEEVYLTAFI LVALLESKTI CNDYVNSLDS
1160 1170 1180 1190 1200
SIKKATNYLL KKYEKLQRPY TTALTAYALA AADQLNDDRV LMAASTGRDH
1210 1220 1230 1240 1250
WEEYNAHTHN IEGTSYALLA LLKMKKFDQT GPIVRWLTDQ NFYGETYGQT
1260 1270 1280 1290 1300
QATVMAFQAL AEYEIQMPTH KDLNLDITIE LPDREVPIRY RINYENALLA
1310 1320 1330 1340 1350
RTVETKLNQD ITVTASGDGK ATMTILTFYN AQLQEKANVC NKFHLNVSVE
1360 1370 1380 1390 1400
NIHLNAMGAK GALMLKICTR YLGEVDSTMT IIDISMLTGF LPDAEDLTRL
1410 1420 1430 1440 1450
SKGVDRYISR YEVDNNMAQK VAVIIYLNKV SHSEDECLHF KILKHFEVGF
1460 1470 1480 1490 1500
IQPGSVKVYS YYNLDEKCTK FYHPDKGTGL LNKICIGNVC RCAGETCSSL
1510 1520 1530 1540 1550
NHQERIDVPL QIEKACETNV DYVYKTKLLR IEEQDGNDIY VMDVLEVIKQ
1560 1570 1580 1590 1600
GTDENPRAKT HQYISQRKCQ EALNLKVNDD YLIWGSRSDL LPTKDKISYI
1610 1620 1630 1640
ITKNTWIERW PHEDECQEEE FQKLCDDFAQ FSYTLTEFGC PT
Length:1,642
Mass (Da):184,518
Last modified:November 1, 1996 - v1
Checksum:i2A71B2BD61D612A3
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U09969 mRNA. Translation: AAA68989.1.
AY497579 Genomic DNA. Translation: AAR89520.1.
AY586272 Genomic DNA. Translation: AAS97956.1.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U09969 mRNA. Translation: AAA68989.1.
AY497579 Genomic DNA. Translation: AAR89520.1.
AY586272 Genomic DNA. Translation: AAS97956.1.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
3FRPX-ray2.61A23-649[»]
B1264-1642[»]
G733-984[»]
3HRZX-ray2.20A23-649[»]
B733-984[»]
C1264-1642[»]
3HS0X-ray3.00A/F23-649[»]
B/G733-984[»]
C/H1264-1642[»]
3PRXX-ray4.30B/D1-1642[»]
3PVMX-ray4.30B/D1-1642[»]
ProteinModelPortaliQ91132.
SMRiQ91132.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

IntActiQ91132. 3 interactors.
MINTiMINT-7906427.

Protein family/group databases

MEROPSiI39.950.

PTM databases

UniCarbKBiQ91132.

Proteomic databases

TopDownProteomicsiQ91132.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Phylogenomic databases

HOVERGENiHBG005110.

Miscellaneous databases

EvolutionaryTraceiQ91132.

Family and domain databases

Gene3Di1.20.91.20. 1 hit.
1.50.10.20. 1 hit.
2.60.40.690. 1 hit.
InterProiIPR009048. A-macroglobulin_rcpt-bd.
IPR011626. A2M_comp.
IPR002890. A2M_N.
IPR011625. A2M_N_2.
IPR000020. Anaphylatoxin/fibulin.
IPR018081. Anaphylatoxin_comp_syst.
IPR001840. Anaphylatoxn_comp_syst_dom.
IPR001599. Macroglobln_a2.
IPR019742. MacrogloblnA2_CS.
IPR019565. MacrogloblnA2_thiol-ester-bond.
IPR001134. Netrin_domain.
IPR018933. Netrin_module_non-TIMP.
IPR008930. Terpenoid_cyclase/PrenylTrfase.
IPR008993. TIMP-like_OB-fold.
[Graphical view]
PfamiPF00207. A2M. 1 hit.
PF07678. A2M_comp. 1 hit.
PF01835. A2M_N. 1 hit.
PF07703. A2M_N_2. 1 hit.
PF07677. A2M_recep. 1 hit.
PF01821. ANATO. 1 hit.
PF01759. NTR. 1 hit.
PF10569. Thiol-ester_cl. 1 hit.
[Graphical view]
PRINTSiPR00004. ANAPHYLATOXN.
SMARTiSM01360. A2M. 1 hit.
SM01359. A2M_N_2. 1 hit.
SM01361. A2M_recep. 1 hit.
SM00104. ANATO. 1 hit.
SM00643. C345C. 1 hit.
[Graphical view]
SUPFAMiSSF47686. SSF47686. 1 hit.
SSF48239. SSF48239. 1 hit.
SSF49410. SSF49410. 1 hit.
SSF50242. SSF50242. 1 hit.
PROSITEiPS00477. ALPHA_2_MACROGLOBULIN. 1 hit.
PS01178. ANAPHYLATOXIN_2. 1 hit.
PS50189. NTR. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiVCO3_NAJKA
AccessioniPrimary (citable) accession number: Q91132
Secondary accession number(s): Q6PQH3, Q6RHR7
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 11, 2004
Last sequence update: November 1, 1996
Last modified: November 2, 2016
This is version 87 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

Miscellaneous

CVF has been used to study the complement pathways and to investigate the role of complement in disease pathophysiology. It has also been used to consume complement to prevent the hyperactive rejection of organs in xenotransplantation and for targeted complement-mediated cell killing. CVF can be safely administered to laboratory animals for temporary depletion of complement activity. Interestingly, it is able to deplete complement in serum from all vertebrates tested, except cobras. The only side effect from massive activation of complement in vivo by CVF has been an acute and fleeting inflammatory injury of the lungs (PubMed:20417224).1 Publication

Keywords - Technical termi

3D-structure

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. SIMILARITY comments
    Index of protein domains and families

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 one 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.