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Protein

Phosphatidylinositol N-acetylglucosaminyltransferase subunit P

Gene

PIGP

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

Functioni

Part of the complex catalyzing the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to phosphatidylinositol, the first step of GPI biosynthesis.

Catalytic activityi

UDP-N-acetyl-D-glucosamine + 1-phosphatidyl-1D-myo-inositol = UDP + 6-(N-acetyl-alpha-D-glucosaminyl)-1-phosphatidyl-1D-myo-inositol.

Pathway:iglycosylphosphatidylinositol-anchor biosynthesis

This protein is involved in the pathway glycosylphosphatidylinositol-anchor biosynthesis, which is part of Glycolipid biosynthesis.
View all proteins of this organism that are known to be involved in the pathway glycosylphosphatidylinositol-anchor biosynthesis and in Glycolipid biosynthesis.

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Glycosyltransferase, Transferase

Keywords - Biological processi

GPI-anchor biosynthesis

Enzyme and pathway databases

BRENDAi2.4.1.198. 2681.
ReactomeiREACT_952. Synthesis of glycosylphosphatidylinositol (GPI).
UniPathwayiUPA00196.

Names & Taxonomyi

Protein namesi
Recommended name:
Phosphatidylinositol N-acetylglucosaminyltransferase subunit P (EC:2.4.1.198)
Alternative name(s):
Down syndrome critical region protein 5
Down syndrome critical region protein C
Phosphatidylinositol-glycan biosynthesis class P protein
Short name:
PIG-P
Gene namesi
Name:PIGP
Synonyms:DCRC, DSCR5, DSCRC
ORF Names:NPD010
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
ProteomesiUP000005640 Componenti: Chromosome 21

Organism-specific databases

HGNCiHGNC:3046. PIGP.

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Transmembranei40 – 6021HelicalSequence AnalysisAdd
BLAST
Transmembranei80 – 10021HelicalSequence AnalysisAdd
BLAST

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Membrane

Pathology & Biotechi

Organism-specific databases

PharmGKBiPA27498.

Polymorphism and mutation databases

BioMutaiPIGP.
DMDMi425906062.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 158158Phosphatidylinositol N-acetylglucosaminyltransferase subunit PPRO_0000191783Add
BLAST

Proteomic databases

PaxDbiP57054.
PRIDEiP57054.

PTM databases

PhosphoSiteiP57054.

Expressioni

Tissue specificityi

Ubiquitous.

Gene expression databases

BgeeiP57054.
CleanExiHS_PIGP.
ExpressionAtlasiP57054. baseline and differential.
GenevisibleiP57054. HS.

Organism-specific databases

HPAiHPA026921.

Interactioni

Subunit structurei

Associates with PIGA, PIGC, PIGH, PIGQ and DPM2. The latter is not essential for activity.

Protein-protein interaction databases

BioGridi119391. 3 interactions.
STRINGi9606.ENSP00000420037.

Structurei

3D structure databases

ProteinModelPortaliP57054.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Sequence similaritiesi

Belongs to the PIGP family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiNOG133279.
GeneTreeiENSGT00390000013771.
HOVERGENiHBG000430.
InParanoidiP57054.
KOiK03861.
OrthoDBiEOG776SRZ.
PhylomeDBiP57054.
TreeFamiTF323799.

Family and domain databases

InterProiIPR013717. PIG-P.
IPR016542. PIG-P_GPI19.
[Graphical view]
PfamiPF08510. PIG-P. 1 hit.
[Graphical view]
PIRSFiPIRSF008765. PIG-P_GPI19. 1 hit.

Sequences (3)i

Sequence statusi: Complete.

This entry describes 3 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform B (identifier: P57054-1) [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
MVPRSTSLAL IVFLFHRLSK APGKMVENSP SPLPERAIYG FVLFLSSQFG
60 70 80 90 100
FILYLVWAFI PESWLNSLGL TYWPQKYWAV ALPVYLLIAI VIGYVLLFGI
110 120 130 140 150
NMMSTSPLDS IHTITDNYAK NQQQKKYQEE AIPALRDISI SEVNQMFFLA

AKELYTKN
Length:158
Mass (Da):18,059
Last modified:November 28, 2012 - v3
Checksum:i924CCEB84C9D2721
GO
Isoform A (identifier: P57054-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     1-24: Missing.

Show »
Length:134
Mass (Da):15,408
Checksum:i47A2122FA663EB64
GO
Isoform C (identifier: P57054-3) [UniParc]FASTAAdd to basket

Also known as: DCRC-S

The sequence of this isoform differs from the canonical sequence as follows:
     1-50: Missing.
     51-52: FI → MV

Show »
Length:108
Mass (Da):12,510
Checksum:iCF1E65158429EE48
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti3 – 31P → S in BAA96872 (PubMed:10814524).Curated
Sequence conflicti90 – 901I → V in BAA96873 (PubMed:10814524).Curated
Sequence conflicti90 – 901I → V in AAF32289 (PubMed:10907851).Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti9 – 91A → T.5 Publications
Corresponds to variant rs2507733 [ dbSNP | Ensembl ].
VAR_061521
Natural varianti118 – 1181Y → C.
Corresponds to variant rs16994704 [ dbSNP | Ensembl ].
VAR_050538
Natural varianti136 – 1361R → S.
Corresponds to variant rs2276231 [ dbSNP | Ensembl ].
VAR_050539

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei1 – 5050Missing in isoform C. 3 PublicationsVSP_004203Add
BLAST
Alternative sequencei1 – 2424Missing in isoform A. 5 PublicationsVSP_004202Add
BLAST
Alternative sequencei51 – 522FI → MV in isoform C. 3 PublicationsVSP_004204

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB037162 mRNA. Translation: BAA96871.1.
AB037163 mRNA. Translation: BAA96872.1.
AB037164 mRNA. Translation: BAA96873.1.
AB035742 mRNA. Translation: BAA95633.1.
AB035743 mRNA. Translation: BAA95634.1.
AB035744 mRNA. Translation: BAA95635.1.
AB035745 mRNA. Translation: BAA95636.1.
AF216305 mRNA. Translation: AAF32289.1.
AB039659 mRNA. Translation: BAB12395.1.
AF237812 mRNA. Translation: AAG09757.1.
BT007053 mRNA. Translation: AAP35702.1.
AK314457 mRNA. Translation: BAG37065.1.
AK316609 mRNA. Translation: BAG38196.1.
AB451328 mRNA. Translation: BAG70142.1.
AB451472 mRNA. Translation: BAG70286.1.
AP000704 Genomic DNA. No translation available.
AP001429 Genomic DNA. No translation available.
AP001431 Genomic DNA. No translation available.
AP001727 Genomic DNA. Translation: BAA95512.1.
CH471079 Genomic DNA. Translation: EAX09724.1.
CH471079 Genomic DNA. Translation: EAX09725.1.
CH471079 Genomic DNA. Translation: EAX09727.1.
CH471079 Genomic DNA. Translation: EAX09726.1.
CH471079 Genomic DNA. Translation: EAX09728.1.
BC005180 mRNA. Translation: AAH05180.1.
BC011007 mRNA. Translation: AAH11007.1.
CCDSiCCDS13649.1. [P57054-1]
CCDS13650.1. [P57054-2]
PIRiJC7301.
JC7302.
RefSeqiNP_710148.1. NM_153681.2.
NP_710149.1. NM_153682.2. [P57054-2]
XP_005261047.1. XM_005260990.3. [P57054-2]
XP_011527897.1. XM_011529595.1. [P57054-2]
XP_011527898.1. XM_011529596.1. [P57054-2]
UniGeneiHs.656565.
Hs.716087.

Genome annotation databases

EnsembliENST00000360525; ENSP00000353719; ENSG00000185808. [P57054-2]
ENST00000399098; ENSP00000382049; ENSG00000185808. [P57054-3]
ENST00000399102; ENSP00000382053; ENSG00000185808. [P57054-2]
ENST00000399103; ENSP00000382054; ENSG00000185808. [P57054-2]
GeneIDi51227.
KEGGihsa:51227.
UCSCiuc002yvw.1. human. [P57054-1]
uc002yvy.2. human. [P57054-3]

Keywords - Coding sequence diversityi

Alternative splicing, Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB037162 mRNA. Translation: BAA96871.1.
AB037163 mRNA. Translation: BAA96872.1.
AB037164 mRNA. Translation: BAA96873.1.
AB035742 mRNA. Translation: BAA95633.1.
AB035743 mRNA. Translation: BAA95634.1.
AB035744 mRNA. Translation: BAA95635.1.
AB035745 mRNA. Translation: BAA95636.1.
AF216305 mRNA. Translation: AAF32289.1.
AB039659 mRNA. Translation: BAB12395.1.
AF237812 mRNA. Translation: AAG09757.1.
BT007053 mRNA. Translation: AAP35702.1.
AK314457 mRNA. Translation: BAG37065.1.
AK316609 mRNA. Translation: BAG38196.1.
AB451328 mRNA. Translation: BAG70142.1.
AB451472 mRNA. Translation: BAG70286.1.
AP000704 Genomic DNA. No translation available.
AP001429 Genomic DNA. No translation available.
AP001431 Genomic DNA. No translation available.
AP001727 Genomic DNA. Translation: BAA95512.1.
CH471079 Genomic DNA. Translation: EAX09724.1.
CH471079 Genomic DNA. Translation: EAX09725.1.
CH471079 Genomic DNA. Translation: EAX09727.1.
CH471079 Genomic DNA. Translation: EAX09726.1.
CH471079 Genomic DNA. Translation: EAX09728.1.
BC005180 mRNA. Translation: AAH05180.1.
BC011007 mRNA. Translation: AAH11007.1.
CCDSiCCDS13649.1. [P57054-1]
CCDS13650.1. [P57054-2]
PIRiJC7301.
JC7302.
RefSeqiNP_710148.1. NM_153681.2.
NP_710149.1. NM_153682.2. [P57054-2]
XP_005261047.1. XM_005260990.3. [P57054-2]
XP_011527897.1. XM_011529595.1. [P57054-2]
XP_011527898.1. XM_011529596.1. [P57054-2]
UniGeneiHs.656565.
Hs.716087.

3D structure databases

ProteinModelPortaliP57054.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi119391. 3 interactions.
STRINGi9606.ENSP00000420037.

PTM databases

PhosphoSiteiP57054.

Polymorphism and mutation databases

BioMutaiPIGP.
DMDMi425906062.

Proteomic databases

PaxDbiP57054.
PRIDEiP57054.

Protocols and materials databases

DNASUi51227.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000360525; ENSP00000353719; ENSG00000185808. [P57054-2]
ENST00000399098; ENSP00000382049; ENSG00000185808. [P57054-3]
ENST00000399102; ENSP00000382053; ENSG00000185808. [P57054-2]
ENST00000399103; ENSP00000382054; ENSG00000185808. [P57054-2]
GeneIDi51227.
KEGGihsa:51227.
UCSCiuc002yvw.1. human. [P57054-1]
uc002yvy.2. human. [P57054-3]

Organism-specific databases

CTDi51227.
GeneCardsiGC21M038435.
HGNCiHGNC:3046. PIGP.
HPAiHPA026921.
MIMi605938. gene.
neXtProtiNX_P57054.
PharmGKBiPA27498.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiNOG133279.
GeneTreeiENSGT00390000013771.
HOVERGENiHBG000430.
InParanoidiP57054.
KOiK03861.
OrthoDBiEOG776SRZ.
PhylomeDBiP57054.
TreeFamiTF323799.

Enzyme and pathway databases

UniPathwayiUPA00196.
BRENDAi2.4.1.198. 2681.
ReactomeiREACT_952. Synthesis of glycosylphosphatidylinositol (GPI).

Miscellaneous databases

ChiTaRSiPIGP. human.
GeneWikiiPIGP.
GenomeRNAii51227.
NextBioi35535499.
PROiP57054.
SOURCEiSearch...

Gene expression databases

BgeeiP57054.
CleanExiHS_PIGP.
ExpressionAtlasiP57054. baseline and differential.
GenevisibleiP57054. HS.

Family and domain databases

InterProiIPR013717. PIG-P.
IPR016542. PIG-P_GPI19.
[Graphical view]
PfamiPF08510. PIG-P. 1 hit.
[Graphical view]
PIRSFiPIRSF008765. PIG-P_GPI19. 1 hit.
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Isolation of two novel genes, DSCR5 and DSCR6, from Down syndrome critical region on human chromosome 21q22.2."
    Shibuya K., Kudoh J., Minoshima S., Kawasaki K., Asakawa S., Shimizu N.
    Biochem. Biophys. Res. Commun. 271:693-698(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS A; B AND C), VARIANT THR-9.
    Tissue: Testis.
  2. "A novel gene, DSCR5, from the distal Down syndrome critical region on chromosome 21q22.2."
    Togashi T., Choi D.-K., Taylor T.D., Suzuki Y., Sugano S., Hattori M., Sakaki Y.
    DNA Res. 7:207-212(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS A; B AND C), VARIANT THR-9.
  3. "Initial enzyme for glycosylphosphatidylinositol biosynthesis requires PIG-P and is regulated by DPM2."
    Watanabe R., Murakami Y., Marmor M.D., Inoue N., Maeda Y., Hino J., Kangawa K., Julius M., Kinoshita T.
    EMBO J. 19:4402-4411(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 26-33, FUNCTION (ISOFORM A).
  4. Song H., Gao G., Peng Y., Ren S., Chen Z., Han Z.
    Submitted (FEB-2000) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM B), VARIANT THR-9.
    Tissue: Pituitary.
  5. "Cloning of human full-length CDSs in BD Creator(TM) system donor vector."
    Kalnine N., Chen X., Rolfs A., Halleck A., Hines L., Eisenstein S., Koundinya M., Raphael J., Moreira D., Kelley T., LaBaer J., Lin Y., Phelan M., Farmer A.
    Submitted (MAY-2003) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM A).
  6. "Complete sequencing and characterization of 21,243 full-length human cDNAs."
    Ota T., Suzuki Y., Nishikawa T., Otsuki T., Sugiyama T., Irie R., Wakamatsu A., Hayashi K., Sato H., Nagai K., Kimura K., Makita H., Sekine M., Obayashi M., Nishi T., Shibahara T., Tanaka T., Ishii S.
    , Yamamoto J., Saito K., Kawai Y., Isono Y., Nakamura Y., Nagahari K., Murakami K., Yasuda T., Iwayanagi T., Wagatsuma M., Shiratori A., Sudo H., Hosoiri T., Kaku Y., Kodaira H., Kondo H., Sugawara M., Takahashi M., Kanda K., Yokoi T., Furuya T., Kikkawa E., Omura Y., Abe K., Kamihara K., Katsuta N., Sato K., Tanikawa M., Yamazaki M., Ninomiya K., Ishibashi T., Yamashita H., Murakawa K., Fujimori K., Tanai H., Kimata M., Watanabe M., Hiraoka S., Chiba Y., Ishida S., Ono Y., Takiguchi S., Watanabe S., Yosida M., Hotuta T., Kusano J., Kanehori K., Takahashi-Fujii A., Hara H., Tanase T.-O., Nomura Y., Togiya S., Komai F., Hara R., Takeuchi K., Arita M., Imose N., Musashino K., Yuuki H., Oshima A., Sasaki N., Aotsuka S., Yoshikawa Y., Matsunawa H., Ichihara T., Shiohata N., Sano S., Moriya S., Momiyama H., Satoh N., Takami S., Terashima Y., Suzuki O., Nakagawa S., Senoh A., Mizoguchi H., Goto Y., Shimizu F., Wakebe H., Hishigaki H., Watanabe T., Sugiyama A., Takemoto M., Kawakami B., Yamazaki M., Watanabe K., Kumagai A., Itakura S., Fukuzumi Y., Fujimori Y., Komiyama M., Tashiro H., Tanigami A., Fujiwara T., Ono T., Yamada K., Fujii Y., Ozaki K., Hirao M., Ohmori Y., Kawabata A., Hikiji T., Kobatake N., Inagaki H., Ikema Y., Okamoto S., Okitani R., Kawakami T., Noguchi S., Itoh T., Shigeta K., Senba T., Matsumura K., Nakajima Y., Mizuno T., Morinaga M., Sasaki M., Togashi T., Oyama M., Hata H., Watanabe M., Komatsu T., Mizushima-Sugano J., Satoh T., Shirai Y., Takahashi Y., Nakagawa K., Okumura K., Nagase T., Nomura N., Kikuchi H., Masuho Y., Yamashita R., Nakai K., Yada T., Nakamura Y., Ohara O., Isogai T., Sugano S.
    Nat. Genet. 36:40-45(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS A AND B), VARIANT THR-9.
    Tissue: Kidney and Umbilical cord blood.
  7. "Human protein factory for converting the transcriptome into an in vitro-expressed proteome."
    Goshima N., Kawamura Y., Fukumoto A., Miura A., Honma R., Satoh R., Wakamatsu A., Yamamoto J., Kimura K., Nishikawa T., Andoh T., Iida Y., Ishikawa K., Ito E., Kagawa N., Kaminaga C., Kanehori K., Kawakami B.
    , Kenmochi K., Kimura R., Kobayashi M., Kuroita T., Kuwayama H., Maruyama Y., Matsuo K., Minami K., Mitsubori M., Mori M., Morishita R., Murase A., Nishikawa A., Nishikawa S., Okamoto T., Sakagami N., Sakamoto Y., Sasaki Y., Seki T., Sono S., Sugiyama A., Sumiya T., Takayama T., Takayama Y., Takeda H., Togashi T., Yahata K., Yamada H., Yanagisawa Y., Endo Y., Imamoto F., Kisu Y., Tanaka S., Isogai T., Imai J., Watanabe S., Nomura N.
    Nat. Methods 5:1011-1017(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM C).
  8. "The DNA sequence of human chromosome 21."
    Hattori M., Fujiyama A., Taylor T.D., Watanabe H., Yada T., Park H.-S., Toyoda A., Ishii K., Totoki Y., Choi D.-K., Groner Y., Soeda E., Ohki M., Takagi T., Sakaki Y., Taudien S., Blechschmidt K., Polley A.
    , Menzel U., Delabar J., Kumpf K., Lehmann R., Patterson D., Reichwald K., Rump A., Schillhabel M., Schudy A., Zimmermann W., Rosenthal A., Kudoh J., Shibuya K., Kawasaki K., Asakawa S., Shintani A., Sasaki T., Nagamine K., Mitsuyama S., Antonarakis S.E., Minoshima S., Shimizu N., Nordsiek G., Hornischer K., Brandt P., Scharfe M., Schoen O., Desario A., Reichelt J., Kauer G., Bloecker H., Ramser J., Beck A., Klages S., Hennig S., Riesselmann L., Dagand E., Wehrmeyer S., Borzym K., Gardiner K., Nizetic D., Francis F., Lehrach H., Reinhardt R., Yaspo M.-L.
    Nature 405:311-319(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  9. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], VARIANT THR-9.
  10. "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
    The MGC Project Team
    Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM A).
    Tissue: Brain.

Entry informationi

Entry nameiPIGP_HUMAN
AccessioniPrimary (citable) accession number: P57054
Secondary accession number(s): B2RB18
, B2RE99, B5BU92, D3DSG7, J3KR75, Q53Y28, Q96KI1, Q9NZA6
Entry historyi
Integrated into UniProtKB/Swiss-Prot: December 1, 2000
Last sequence update: November 28, 2012
Last modified: July 22, 2015
This is version 123 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

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 21
    Human chromosome 21: 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. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  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.