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Protein

Endoplasmic reticulum aminopeptidase 2

Gene

ERAP2

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

Functioni

Aminopeptidase that plays a central role in peptide trimming, a step required for the generation of most HLA class I-binding peptides. Peptide trimming is essential to customize longer precursor peptides to fit them to the correct length required for presentation on MHC class I molecules. Preferentially hydrolyzes the basic residues Arg and Lys.3 Publications

Cofactori

Zn2+By similarityNote: Binds 1 zinc ion per subunit.By similarity

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei200Substrate1 Publication1
Metal bindingi370Zinc; catalytic1
Active sitei371Proton acceptorPROSITE-ProRule annotation1 Publication1
Metal bindingi374Zinc; catalytic1
Metal bindingi393Zinc; catalytic1
Sitei455Transition state stabilizer1

GO - Molecular functioni

  • aminopeptidase activity Source: HGNC
  • endopeptidase activity Source: Reactome
  • metalloaminopeptidase activity Source: GO_Central
  • metallopeptidase activity Source: HGNC
  • peptide binding Source: GO_Central
  • zinc ion binding Source: HGNC

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Aminopeptidase, Hydrolase, Metalloprotease, Protease

Keywords - Biological processi

Adaptive immunity, Immunity

Keywords - Ligandi

Metal-binding, Zinc

Enzyme and pathway databases

BRENDAi3.4.11.1. 2681.
3.4.11.6. 2681.
ReactomeiR-HSA-983170. Antigen Presentation: Folding, assembly and peptide loading of class I MHC.
SABIO-RKQ6P179.

Protein family/group databases

MEROPSiM01.024.

Names & Taxonomyi

Protein namesi
Recommended name:
Endoplasmic reticulum aminopeptidase 2 (EC:3.4.11.-)
Alternative name(s):
Leukocyte-derived arginine aminopeptidase
Short name:
L-RAP
Gene namesi
Name:ERAP2
Synonyms:LRAP
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 5

Organism-specific databases

HGNCiHGNC:29499. ERAP2.

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 20CytoplasmicSequence analysisAdd BLAST20
Transmembranei21 – 40Helical; Signal-anchor for type II membrane proteinSequence analysisAdd BLAST20
Topological domaini41 – 960LumenalSequence analysisAdd BLAST920

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Endoplasmic reticulum, Membrane

Pathology & Biotechi

Organism-specific databases

DisGeNETi64167.
OpenTargetsiENSG00000164308.
PharmGKBiPA162385208.

Chemistry databases

ChEMBLiCHEMBL5043.
GuidetoPHARMACOLOGYi1567.

Polymorphism and mutation databases

BioMutaiERAP2.
DMDMi166232401.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00003157191 – 960Endoplasmic reticulum aminopeptidase 2Add BLAST960

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Glycosylationi85N-linked (GlcNAc...)1 Publication1
Glycosylationi119N-linked (GlcNAc...)1 Publication1
Glycosylationi405N-linked (GlcNAc...)1 Publication1
Disulfide bondi421 ↔ 4601 Publication
Glycosylationi650N-linked (GlcNAc...)1 Publication1
Disulfide bondi759 ↔ 7661 Publication

Post-translational modificationi

N-glycosylated.3 Publications

Keywords - PTMi

Disulfide bond, Glycoprotein

Proteomic databases

EPDiQ6P179.
MaxQBiQ6P179.
PaxDbiQ6P179.
PeptideAtlasiQ6P179.
PRIDEiQ6P179.

PTM databases

iPTMnetiQ6P179.
PhosphoSitePlusiQ6P179.

Expressioni

Tissue specificityi

Ubiquitously expressed. Highly expressed in spleen and leukocytes.1 Publication

Inductioni

By IFNG/IFN-gamma.2 Publications

Gene expression databases

BgeeiENSG00000164308.
CleanExiHS_ERAP2.
ExpressionAtlasiQ6P179. baseline and differential.
GenevisibleiQ6P179. HS.

Organism-specific databases

HPAiCAB025618.
HPA034498.

Interactioni

Subunit structurei

Heterodimer with ERAP1.2 Publications

Protein-protein interaction databases

BioGridi122092. 1 interactor.
IntActiQ6P179. 2 interactors.
STRINGi9606.ENSP00000400376.

Chemistry databases

BindingDBiQ6P179.

Structurei

Secondary structure

1960
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi57 – 60Combined sources4
Beta strandi66 – 68Combined sources3
Beta strandi71 – 85Combined sources15
Turni86 – 89Combined sources4
Beta strandi90 – 101Combined sources12
Beta strandi106 – 111Combined sources6
Beta strandi116 – 123Combined sources8
Helixi128 – 130Combined sources3
Beta strandi138 – 142Combined sources5
Helixi143 – 145Combined sources3
Beta strandi147 – 151Combined sources5
Beta strandi160 – 171Combined sources12
Beta strandi173 – 185Combined sources13
Beta strandi187 – 189Combined sources3
Beta strandi191 – 198Combined sources8
Turni200 – 203Combined sources4
Helixi204 – 206Combined sources3
Beta strandi218 – 226Combined sources9
Beta strandi231 – 236Combined sources6
Beta strandi238 – 243Combined sources6
Beta strandi249 – 253Combined sources5
Helixi261 – 263Combined sources3
Beta strandi266 – 269Combined sources4
Beta strandi272 – 277Combined sources6
Beta strandi283 – 288Combined sources6
Helixi290 – 296Combined sources7
Helixi297 – 314Combined sources18
Beta strandi320 – 330Combined sources11
Beta strandi332 – 336Combined sources5
Beta strandi341 – 345Combined sources5
Helixi346 – 349Combined sources4
Turni353 – 355Combined sources3
Helixi358 – 376Combined sources19
Turni378 – 380Combined sources3
Beta strandi381 – 385Combined sources5
Helixi386 – 388Combined sources3
Helixi389 – 407Combined sources19
Helixi409 – 411Combined sources3
Helixi413 – 415Combined sources3
Helixi418 – 428Combined sources11
Helixi443 – 448Combined sources6
Turni452 – 455Combined sources4
Helixi456 – 469Combined sources14
Helixi471 – 485Combined sources15
Beta strandi488 – 490Combined sources3
Helixi492 – 500Combined sources9
Beta strandi504 – 507Combined sources4
Beta strandi510 – 517Combined sources8
Helixi522 – 543Combined sources22
Beta strandi548 – 553Combined sources6
Beta strandi558 – 565Combined sources8
Turni575 – 583Combined sources9
Beta strandi588 – 594Combined sources7
Beta strandi597 – 605Combined sources9
Beta strandi607 – 613Combined sources7
Beta strandi621 – 624Combined sources4
Helixi625 – 627Combined sources3
Beta strandi629 – 635Combined sources7
Turni636 – 638Combined sources3
Helixi639 – 650Combined sources12
Helixi651 – 653Combined sources3
Helixi656 – 671Combined sources16
Beta strandi673 – 675Combined sources3
Helixi677 – 683Combined sources7
Helixi684 – 688Combined sources5
Helixi693 – 712Combined sources20
Helixi716 – 728Combined sources13
Helixi731 – 735Combined sources5
Beta strandi739 – 741Combined sources3
Helixi745 – 760Combined sources16
Helixi764 – 779Combined sources16
Turni780 – 782Combined sources3
Helixi788 – 790Combined sources3
Helixi791 – 798Combined sources8
Helixi802 – 814Combined sources13
Helixi818 – 829Combined sources12
Helixi834 – 846Combined sources13
Beta strandi848 – 850Combined sources3
Helixi852 – 854Combined sources3
Helixi855 – 863Combined sources9
Helixi866 – 878Combined sources13
Helixi880 – 886Combined sources7
Helixi892 – 902Combined sources11
Helixi908 – 921Combined sources14
Turni922 – 925Combined sources4
Helixi929 – 960Combined sources32

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
3SE6X-ray3.08A/B1-960[»]
4E36X-ray3.22A/B1-960[»]
4JBSX-ray2.79A/B3-960[»]
5AB0X-ray2.50A/C1-960[»]
5AB2X-ray2.73A/B1-960[»]
5CU5X-ray3.02A/B1-960[»]
ProteinModelPortaliQ6P179.
SMRiQ6P179.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni334 – 338Substrate binding5

Sequence similaritiesi

Belongs to the peptidase M1 family.Curated

Keywords - Domaini

Signal-anchor, Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG1046. Eukaryota.
COG0308. LUCA.
GeneTreeiENSGT00760000119082.
HOGENOMiHOG000106482.
HOVERGENiHBG108296.
InParanoidiQ6P179.
KOiK13723.
OMAiHYEGHGW.
OrthoDBiEOG091G01GH.
PhylomeDBiQ6P179.
TreeFamiTF300395.

Family and domain databases

InterProiIPR024571. ERAP1-like_C_dom.
IPR033528. ERAP2.
IPR001930. Peptidase_M1.
IPR014782. Peptidase_M1_N.
[Graphical view]
PANTHERiPTHR11533. PTHR11533. 2 hits.
PTHR11533:SF166. PTHR11533:SF166. 2 hits.
PfamiPF11838. ERAP1_C. 1 hit.
PF01433. Peptidase_M1. 1 hit.
[Graphical view]
PRINTSiPR00756. ALADIPTASE.
PROSITEiPS00142. ZINC_PROTEASE. 1 hit.
[Graphical view]

Sequences (4)i

Sequence statusi: Complete.

This entry describes 4 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: Q6P179-1) [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
MFHSSAMVNS HRKPMFNIHR GFYCLTAILP QICICSQFSV PSSYHFTEDP
60 70 80 90 100
GAFPVATNGE RFPWQELRLP SVVIPLHYDL FVHPNLTSLD FVASEKIEVL
110 120 130 140 150
VSNATQFIIL HSKDLEITNA TLQSEEDSRY MKPGKELKVL SYPAHEQIAL
160 170 180 190 200
LVPEKLTPHL KYYVAMDFQA KLGDGFEGFY KSTYRTLGGE TRILAVTDFE
210 220 230 240 250
PTQARMAFPC FDEPLFKANF SIKIRRESRH IALSNMPKVK TIELEGGLLE
260 270 280 290 300
DHFETTVKMS TYLVAYIVCD FHSLSGFTSS GVKVSIYASP DKRNQTHYAL
310 320 330 340 350
QASLKLLDFY EKYFDIYYPL SKLDLIAIPD FAPGAMENWG LITYRETSLL
360 370 380 390 400
FDPKTSSASD KLWVTRVIAH ELAHQWFGNL VTMEWWNDIW LKEGFAKYME
410 420 430 440 450
LIAVNATYPE LQFDDYFLNV CFEVITKDSL NSSRPISKPA ETPTQIQEMF
460 470 480 490 500
DEVSYNKGAC ILNMLKDFLG EEKFQKGIIQ YLKKFSYRNA KNDDLWSSLS
510 520 530 540 550
NSCLESDFTS GGVCHSDPKM TSNMLAFLGE NAEVKEMMTT WTLQKGIPLL
560 570 580 590 600
VVKQDGCSLR LQQERFLQGV FQEDPEWRAL QERYLWHIPL TYSTSSSNVI
610 620 630 640 650
HRHILKSKTD TLDLPEKTSW VKFNVDSNGY YIVHYEGHGW DQLITQLNQN
660 670 680 690 700
HTLLRPKDRV GLIHDVFQLV GAGRLTLDKA LDMTYYLQHE TSSPALLEGL
710 720 730 740 750
SYLESFYHMM DRRNISDISE NLKRYLLQYF KPVIDRQSWS DKGSVWDRML
760 770 780 790 800
RSALLKLACD LNHAPCIQKA AELFSQWMES SGKLNIPTDV LKIVYSVGAQ
810 820 830 840 850
TTAGWNYLLE QYELSMSSAE QNKILYALST SKHQEKLLKL IELGMEGKVI
860 870 880 890 900
KTQNLAALLH AIARRPKGQQ LAWDFVRENW THLLKKFDLG SYDIRMIISG
910 920 930 940 950
TTAHFSSKDK LQEVKLFFES LEAQGSHLDI FQTVLETITK NIKWLEKNLP
960
TLRTWLMVNT
Length:960
Mass (Da):110,462
Last modified:January 15, 2008 - v2
Checksum:i261EFC06870D644E
GO
Isoform 2 (identifier: Q6P179-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     525-532: LAFLGENA → VRIKRVTE
     533-960: Missing.

Show »
Length:532
Mass (Da):60,952
Checksum:iDA0F49B61F79B920
GO
Isoform 3 (identifier: Q6P179-3) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     238-282: Missing.

Note: No experimental confirmation available.
Show »
Length:915
Mass (Da):105,526
Checksum:i10075BE1C076377F
GO
Isoform 4 (identifier: Q6P179-4) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     324-350: DLIAIPDFAPGAMENWGLITYRETSLL → GMFKFHIIVFIFAHKTCFDLFPLSLSM
     351-960: Missing.

Note: No experimental confirmation available.
Show »
Length:350
Mass (Da):40,088
Checksum:i189B8EF5D9D4BD11
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti129R → K in AAH17927 (PubMed:15489334).Curated1

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_038285214P → L.Corresponds to variant rs3733905dbSNPEnsembl.1
Natural variantiVAR_038286392K → N.2 PublicationsCorresponds to variant rs2549782dbSNPEnsembl.1
Natural variantiVAR_051569411L → R.Corresponds to variant rs34261036dbSNPEnsembl.1
Natural variantiVAR_038287669L → Q.Corresponds to variant rs17408150dbSNPEnsembl.1

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_030671238 – 282Missing in isoform 3. 1 PublicationAdd BLAST45
Alternative sequenceiVSP_030672324 – 350DLIAI…ETSLL → GMFKFHIIVFIFAHKTCFDL FPLSLSM in isoform 4. 1 PublicationAdd BLAST27
Alternative sequenceiVSP_030673351 – 960Missing in isoform 4. 1 PublicationAdd BLAST610
Alternative sequenceiVSP_030674525 – 532LAFLGENA → VRIKRVTE in isoform 2. 1 Publication8
Alternative sequenceiVSP_030675533 – 960Missing in isoform 2. 1 PublicationAdd BLAST428

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB109031 mRNA. Translation: BAC78818.1.
AB163917 mRNA. Translation: BAD90015.1.
AY028805 mRNA. Translation: AAK37776.1.
AF191545 mRNA. Translation: AAG28383.1.
CH471084 Genomic DNA. Translation: EAW96080.1.
BC065240 mRNA. Translation: AAH65240.1.
BC017927 mRNA. Translation: AAH17927.1.
CCDSiCCDS4086.1. [Q6P179-1]
RefSeqiNP_001123612.1. NM_001130140.2. [Q6P179-1]
NP_001316158.1. NM_001329229.1. [Q6P179-3]
NP_001316162.1. NM_001329233.1. [Q6P179-4]
NP_071745.1. NM_022350.4. [Q6P179-1]
UniGeneiHs.482910.

Genome annotation databases

EnsembliENST00000379904; ENSP00000369235; ENSG00000164308. [Q6P179-3]
ENST00000437043; ENSP00000400376; ENSG00000164308. [Q6P179-1]
ENST00000510309; ENSP00000425758; ENSG00000164308. [Q6P179-4]
ENST00000513084; ENSP00000421849; ENSG00000164308. [Q6P179-2]
GeneIDi64167.
KEGGihsa:64167.
UCSCiuc003kmq.4. human. [Q6P179-1]

Keywords - Coding sequence diversityi

Alternative splicing, Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB109031 mRNA. Translation: BAC78818.1.
AB163917 mRNA. Translation: BAD90015.1.
AY028805 mRNA. Translation: AAK37776.1.
AF191545 mRNA. Translation: AAG28383.1.
CH471084 Genomic DNA. Translation: EAW96080.1.
BC065240 mRNA. Translation: AAH65240.1.
BC017927 mRNA. Translation: AAH17927.1.
CCDSiCCDS4086.1. [Q6P179-1]
RefSeqiNP_001123612.1. NM_001130140.2. [Q6P179-1]
NP_001316158.1. NM_001329229.1. [Q6P179-3]
NP_001316162.1. NM_001329233.1. [Q6P179-4]
NP_071745.1. NM_022350.4. [Q6P179-1]
UniGeneiHs.482910.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
3SE6X-ray3.08A/B1-960[»]
4E36X-ray3.22A/B1-960[»]
4JBSX-ray2.79A/B3-960[»]
5AB0X-ray2.50A/C1-960[»]
5AB2X-ray2.73A/B1-960[»]
5CU5X-ray3.02A/B1-960[»]
ProteinModelPortaliQ6P179.
SMRiQ6P179.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi122092. 1 interactor.
IntActiQ6P179. 2 interactors.
STRINGi9606.ENSP00000400376.

Chemistry databases

BindingDBiQ6P179.
ChEMBLiCHEMBL5043.
GuidetoPHARMACOLOGYi1567.

Protein family/group databases

MEROPSiM01.024.

PTM databases

iPTMnetiQ6P179.
PhosphoSitePlusiQ6P179.

Polymorphism and mutation databases

BioMutaiERAP2.
DMDMi166232401.

Proteomic databases

EPDiQ6P179.
MaxQBiQ6P179.
PaxDbiQ6P179.
PeptideAtlasiQ6P179.
PRIDEiQ6P179.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000379904; ENSP00000369235; ENSG00000164308. [Q6P179-3]
ENST00000437043; ENSP00000400376; ENSG00000164308. [Q6P179-1]
ENST00000510309; ENSP00000425758; ENSG00000164308. [Q6P179-4]
ENST00000513084; ENSP00000421849; ENSG00000164308. [Q6P179-2]
GeneIDi64167.
KEGGihsa:64167.
UCSCiuc003kmq.4. human. [Q6P179-1]

Organism-specific databases

CTDi64167.
DisGeNETi64167.
GeneCardsiERAP2.
H-InvDBHIX0005053.
HGNCiHGNC:29499. ERAP2.
HPAiCAB025618.
HPA034498.
MIMi609497. gene.
neXtProtiNX_Q6P179.
OpenTargetsiENSG00000164308.
PharmGKBiPA162385208.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG1046. Eukaryota.
COG0308. LUCA.
GeneTreeiENSGT00760000119082.
HOGENOMiHOG000106482.
HOVERGENiHBG108296.
InParanoidiQ6P179.
KOiK13723.
OMAiHYEGHGW.
OrthoDBiEOG091G01GH.
PhylomeDBiQ6P179.
TreeFamiTF300395.

Enzyme and pathway databases

BRENDAi3.4.11.1. 2681.
3.4.11.6. 2681.
ReactomeiR-HSA-983170. Antigen Presentation: Folding, assembly and peptide loading of class I MHC.
SABIO-RKQ6P179.

Miscellaneous databases

GenomeRNAii64167.
PROiQ6P179.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000164308.
CleanExiHS_ERAP2.
ExpressionAtlasiQ6P179. baseline and differential.
GenevisibleiQ6P179. HS.

Family and domain databases

InterProiIPR024571. ERAP1-like_C_dom.
IPR033528. ERAP2.
IPR001930. Peptidase_M1.
IPR014782. Peptidase_M1_N.
[Graphical view]
PANTHERiPTHR11533. PTHR11533. 2 hits.
PTHR11533:SF166. PTHR11533:SF166. 2 hits.
PfamiPF11838. ERAP1_C. 1 hit.
PF01433. Peptidase_M1. 1 hit.
[Graphical view]
PRINTSiPR00756. ALADIPTASE.
PROSITEiPS00142. ZINC_PROTEASE. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiERAP2_HUMAN
AccessioniPrimary (citable) accession number: Q6P179
Secondary accession number(s): Q7Z5K1
, Q8TD32, Q8WVJ4, Q9HBX2
Entry historyi
Integrated into UniProtKB/Swiss-Prot: January 15, 2008
Last sequence update: January 15, 2008
Last modified: November 30, 2016
This is version 117 of the entry and version 2 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

Miscellaneous

Defects in the expression of this gene may cause improper antigen processing, possibly leading to favor tumor escape from the immune surveillance.

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Human chromosome 5
    Human chromosome 5: 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. Peptidase families
    Classification of peptidase families and list of entries
  7. 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.