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Protein

Estradiol 17-beta-dehydrogenase 8

Gene

HSD17B8

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

Functioni

NAD-dependent 17-beta-hydroxysteroid dehydrogenase with highest activity towards estradiol. Has very low activity towards testosterone. The heteroteramer with CBR4 has NADH-dependent 3-ketoacyl-acyl carrier protein reductase activity. May play a role in biosynthesis of fatty acids in mitochondria.2 Publications

Catalytic activityi

17-beta-estradiol + NAD(P)+ = estrone + NAD(P)H.
Testosterone + NAD+ = androstenedione + NADH.

Pathwayi: estrogen biosynthesis

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

Pathwayi: fatty acid biosynthesis

This protein is involved in the pathway fatty acid biosynthesis, which is part of Lipid metabolism.
View all proteins of this organism that are known to be involved in the pathway fatty acid biosynthesis and in Lipid metabolism.

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Binding sitei156 – 1561SubstrateBy similarity
Active sitei169 – 1691Proton acceptorPROSITE-ProRule annotation

Regions

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Nucleotide bindingi15 – 239NAD1 Publication
Nucleotide bindingi42 – 432NAD1 Publication
Nucleotide bindingi74 – 763NAD1 Publication
Nucleotide bindingi169 – 1735NAD1 Publication
Nucleotide bindingi202 – 2043NAD1 Publication

GO - Molecular functioni

  • 3-hydroxyacyl-CoA dehydrogenase activity Source: UniProtKB
  • estradiol 17-beta-dehydrogenase activity Source: UniProtKB
  • testosterone dehydrogenase (NAD+) activity Source: UniProtKB-EC

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase

Keywords - Biological processi

Fatty acid biosynthesis, Fatty acid metabolism, Lipid biosynthesis, Lipid metabolism, Steroid biosynthesis

Keywords - Ligandi

NAD

Enzyme and pathway databases

SABIO-RKQ92506.
UniPathwayiUPA00094.
UPA00769.

Chemistry

SwissLipidsiSLP:000001271.

Names & Taxonomyi

Protein namesi
Recommended name:
Estradiol 17-beta-dehydrogenase 8 (EC:1.1.1.62)
Alternative name(s):
17-beta-hydroxysteroid dehydrogenase 8
Short name:
17-beta-HSD 8
3-oxoacyl-[acyl-carrier-protein] reductase (EC:1.1.1.-)
Protein Ke6
Short name:
Ke-6
Really interesting new gene 2 protein
Short chain dehydrogenase/reductase family 30C member 1
Testosterone 17-beta-dehydrogenase 8 (EC:1.1.1.239)
Gene namesi
Name:HSD17B8
Synonyms:FABGL, HKE6, RING2, SDR30C1
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 6

Organism-specific databases

HGNCiHGNC:3554. HSD17B8.

Subcellular locationi

GO - Cellular componenti

  • mitochondrial envelope Source: Ensembl
  • mitochondrial matrix Source: UniProtKB
  • plasma membrane Source: Ensembl
Complete GO annotation...

Keywords - Cellular componenti

Mitochondrion

Pathology & Biotechi

Organism-specific databases

PharmGKBiPA29484.

Polymorphism and mutation databases

BioMutaiHSD17B8.
DMDMi12643402.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 261261Estradiol 17-beta-dehydrogenase 8PRO_0000054598Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei60 – 601PhosphoserineBy similarity
Modified residuei160 – 1601N6-succinyllysineBy similarity
Modified residuei173 – 1731N6-succinyllysineBy similarity

Keywords - PTMi

Phosphoprotein

Proteomic databases

EPDiQ92506.
MaxQBiQ92506.
PaxDbiQ92506.
PRIDEiQ92506.
TopDownProteomicsiQ92506.

PTM databases

iPTMnetiQ92506.
PhosphoSiteiQ92506.

Expressioni

Tissue specificityi

Highly expressed in placenta, liver and pancreas, lower in the skeletal muscle and kidney. Widely expressed.1 Publication

Inductioni

Up-regulated by estradiol.1 Publication

Gene expression databases

BgeeiQ92506.
CleanExiHS_HSD17B8.
GenevisibleiQ92506. HS.

Organism-specific databases

HPAiHPA042132.

Interactioni

Subunit structurei

Heterotetramer with CBR4; contains two molecules of HSD17B8 and CBR4.1 Publication

Protein-protein interaction databases

BioGridi113653. 16 interactions.
IntActiQ92506. 2 interactions.
STRINGi9606.ENSP00000363794.

Structurei

Secondary structure

1
261
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Turni8 – 114Combined sources
Beta strandi13 – 175Combined sources
Turni18 – 203Combined sources
Helixi22 – 3312Combined sources
Beta strandi37 – 448Combined sources
Helixi45 – 539Combined sources
Beta strandi70 – 734Combined sources
Helixi79 – 9315Combined sources
Beta strandi98 – 1025Combined sources
Helixi112 – 1143Combined sources
Helixi117 – 12711Combined sources
Helixi129 – 14517Combined sources
Beta strandi149 – 1546Combined sources
Helixi158 – 1614Combined sources
Helixi167 – 18721Combined sources
Helixi188 – 1903Combined sources
Beta strandi192 – 1998Combined sources
Beta strandi201 – 2044Combined sources
Turni207 – 2093Combined sources
Helixi212 – 2165Combined sources
Helixi219 – 2213Combined sources
Helixi230 – 24112Combined sources
Helixi243 – 2453Combined sources
Beta strandi252 – 2565Combined sources
Turni257 – 2604Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2PD6X-ray2.00A/B/C/D6-261[»]
4CQLX-ray2.85A/D/E/H/I/L/M/P1-261[»]
4CQMX-ray2.34A/D/E/H/I/L/M/P1-261[»]
ProteinModelPortaliQ92506.
SMRiQ92506. Positions 6-261.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ92506.

Family & Domainsi

Sequence similaritiesi

Phylogenomic databases

eggNOGiKOG1200. Eukaryota.
COG1028. LUCA.
GeneTreeiENSGT00760000118868.
HOVERGENiHBG002145.
InParanoidiQ92506.
KOiK13370.
OMAiWREMIEV.
OrthoDBiEOG73Z2VD.
PhylomeDBiQ92506.
TreeFamiTF313099.

Family and domain databases

Gene3Di3.40.50.720. 1 hit.
InterProiIPR016040. NAD(P)-bd_dom.
IPR020904. Sc_DH/Rdtase_CS.
IPR002347. SDR_fam.
[Graphical view]
PANTHERiPTHR24322. PTHR24322. 2 hits.
PRINTSiPR00081. GDHRDH.
PR00080. SDRFAMILY.
SUPFAMiSSF51735. SSF51735. 1 hit.
PROSITEiPS00061. ADH_SHORT. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Q92506-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MASQLQNRLR SALALVTGAG SGIGRAVSVR LAGEGATVAA CDLDRAAAQE
60 70 80 90 100
TVRLLGGPGS KEGPPRGNHA AFQADVSEAR AARCLLEQVQ ACFSRPPSVV
110 120 130 140 150
VSCAGITQDE FLLHMSEDDW DKVIAVNLKG TFLVTQAAAQ ALVSNGCRGS
160 170 180 190 200
IINISSIVGK VGNVGQTNYA ASKAGVIGLT QTAARELGRH GIRCNSVLPG
210 220 230 240 250
FIATPMTQKV PQKVVDKITE MIPMGHLGDP EDVADVVAFL ASEDSGYITG
260
TSVEVTGGLF M
Length:261
Mass (Da):26,974
Last modified:January 24, 2001 - v2
Checksum:i8B8B2D7131714D71
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti117 – 1171E → R in BAA11529 (PubMed:8812499).Curated
Sequence conflicti193 – 1931R → P in BAA11529 (PubMed:8812499).Curated
Sequence conflicti208 – 2081Q → K in BAA11529 (PubMed:8812499).Curated
Sequence conflicti212 – 2121Q → K in BAA11529 (PubMed:8812499).Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti158 – 1581V → L in a breast cancer sample; somatic mutation. 1 Publication
VAR_035844
Natural varianti190 – 1901H → R.
Corresponds to variant rs34491699 [ dbSNP | Ensembl ].
VAR_052316

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
BT007239 mRNA. Translation: AAP35903.1.
AL031228 Genomic DNA. Translation: CAC38444.1.
AL662824, AL713971 Genomic DNA. Translation: CAI17616.1.
AL713971, AL662824 Genomic DNA. Translation: CAI17657.1.
AL645940 Genomic DNA. Translation: CAI18068.1.
AL844527 Genomic DNA. Translation: CAI41840.1.
CR759786 Genomic DNA. Translation: CAQ08245.1.
CR759733 Genomic DNA. Translation: CAQ10302.1.
CR847841 Genomic DNA. Translation: CAQ10313.1.
CH471081 Genomic DNA. Translation: EAX03682.1.
BC008185 mRNA. Translation: AAH08185.1.
D82061 mRNA. Translation: BAA11529.1.
CCDSiCCDS4769.1.
RefSeqiNP_055049.1. NM_014234.4.
UniGeneiHs.415058.

Genome annotation databases

EnsembliENST00000230236; ENSP00000230236; ENSG00000112474.
ENST00000374662; ENSP00000363794; ENSG00000204228.
ENST00000414463; ENSP00000387753; ENSG00000228357.
ENST00000422433; ENSP00000406488; ENSG00000232357.
ENST00000427295; ENSP00000403538; ENSG00000228712.
ENST00000454191; ENSP00000413950; ENSG00000225312.
GeneIDi7923.
KEGGihsa:7923.
UCSCiuc003odi.3. human.

Keywords - Coding sequence diversityi

Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
BT007239 mRNA. Translation: AAP35903.1.
AL031228 Genomic DNA. Translation: CAC38444.1.
AL662824, AL713971 Genomic DNA. Translation: CAI17616.1.
AL713971, AL662824 Genomic DNA. Translation: CAI17657.1.
AL645940 Genomic DNA. Translation: CAI18068.1.
AL844527 Genomic DNA. Translation: CAI41840.1.
CR759786 Genomic DNA. Translation: CAQ08245.1.
CR759733 Genomic DNA. Translation: CAQ10302.1.
CR847841 Genomic DNA. Translation: CAQ10313.1.
CH471081 Genomic DNA. Translation: EAX03682.1.
BC008185 mRNA. Translation: AAH08185.1.
D82061 mRNA. Translation: BAA11529.1.
CCDSiCCDS4769.1.
RefSeqiNP_055049.1. NM_014234.4.
UniGeneiHs.415058.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2PD6X-ray2.00A/B/C/D6-261[»]
4CQLX-ray2.85A/D/E/H/I/L/M/P1-261[»]
4CQMX-ray2.34A/D/E/H/I/L/M/P1-261[»]
ProteinModelPortaliQ92506.
SMRiQ92506. Positions 6-261.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi113653. 16 interactions.
IntActiQ92506. 2 interactions.
STRINGi9606.ENSP00000363794.

Chemistry

SwissLipidsiSLP:000001271.

PTM databases

iPTMnetiQ92506.
PhosphoSiteiQ92506.

Polymorphism and mutation databases

BioMutaiHSD17B8.
DMDMi12643402.

Proteomic databases

EPDiQ92506.
MaxQBiQ92506.
PaxDbiQ92506.
PRIDEiQ92506.
TopDownProteomicsiQ92506.

Protocols and materials databases

DNASUi7923.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000230236; ENSP00000230236; ENSG00000112474.
ENST00000374662; ENSP00000363794; ENSG00000204228.
ENST00000414463; ENSP00000387753; ENSG00000228357.
ENST00000422433; ENSP00000406488; ENSG00000232357.
ENST00000427295; ENSP00000403538; ENSG00000228712.
ENST00000454191; ENSP00000413950; ENSG00000225312.
GeneIDi7923.
KEGGihsa:7923.
UCSCiuc003odi.3. human.

Organism-specific databases

CTDi7923.
GeneCardsiHSD17B8.
HGNCiHGNC:3554. HSD17B8.
HPAiHPA042132.
MIMi601417. gene.
neXtProtiNX_Q92506.
PharmGKBiPA29484.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG1200. Eukaryota.
COG1028. LUCA.
GeneTreeiENSGT00760000118868.
HOVERGENiHBG002145.
InParanoidiQ92506.
KOiK13370.
OMAiWREMIEV.
OrthoDBiEOG73Z2VD.
PhylomeDBiQ92506.
TreeFamiTF313099.

Enzyme and pathway databases

UniPathwayiUPA00094.
UPA00769.
SABIO-RKQ92506.

Miscellaneous databases

ChiTaRSiHSD17B8. human.
EvolutionaryTraceiQ92506.
GeneWikiiHSD17B8.
GenomeRNAii7923.
PROiQ92506.
SOURCEiSearch...

Gene expression databases

BgeeiQ92506.
CleanExiHS_HSD17B8.
GenevisibleiQ92506. HS.

Family and domain databases

Gene3Di3.40.50.720. 1 hit.
InterProiIPR016040. NAD(P)-bd_dom.
IPR020904. Sc_DH/Rdtase_CS.
IPR002347. SDR_fam.
[Graphical view]
PANTHERiPTHR24322. PTHR24322. 2 hits.
PRINTSiPR00081. GDHRDH.
PR00080. SDRFAMILY.
SUPFAMiSSF51735. SSF51735. 1 hit.
PROSITEiPS00061. ADH_SHORT. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "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].
  2. "The DNA sequence and analysis of human chromosome 6."
    Mungall A.J., Palmer S.A., Sims S.K., Edwards C.A., Ashurst J.L., Wilming L., Jones M.C., Horton R., Hunt S.E., Scott C.E., Gilbert J.G.R., Clamp M.E., Bethel G., Milne S., Ainscough R., Almeida J.P., Ambrose K.D., Andrews T.D.
    , Ashwell R.I.S., Babbage A.K., Bagguley C.L., Bailey J., Banerjee R., Barker D.J., Barlow K.F., Bates K., Beare D.M., Beasley H., Beasley O., Bird C.P., Blakey S.E., Bray-Allen S., Brook J., Brown A.J., Brown J.Y., Burford D.C., Burrill W., Burton J., Carder C., Carter N.P., Chapman J.C., Clark S.Y., Clark G., Clee C.M., Clegg S., Cobley V., Collier R.E., Collins J.E., Colman L.K., Corby N.R., Coville G.J., Culley K.M., Dhami P., Davies J., Dunn M., Earthrowl M.E., Ellington A.E., Evans K.A., Faulkner L., Francis M.D., Frankish A., Frankland J., French L., Garner P., Garnett J., Ghori M.J., Gilby L.M., Gillson C.J., Glithero R.J., Grafham D.V., Grant M., Gribble S., Griffiths C., Griffiths M.N.D., Hall R., Halls K.S., Hammond S., Harley J.L., Hart E.A., Heath P.D., Heathcott R., Holmes S.J., Howden P.J., Howe K.L., Howell G.R., Huckle E., Humphray S.J., Humphries M.D., Hunt A.R., Johnson C.M., Joy A.A., Kay M., Keenan S.J., Kimberley A.M., King A., Laird G.K., Langford C., Lawlor S., Leongamornlert D.A., Leversha M., Lloyd C.R., Lloyd D.M., Loveland J.E., Lovell J., Martin S., Mashreghi-Mohammadi M., Maslen G.L., Matthews L., McCann O.T., McLaren S.J., McLay K., McMurray A., Moore M.J.F., Mullikin J.C., Niblett D., Nickerson T., Novik K.L., Oliver K., Overton-Larty E.K., Parker A., Patel R., Pearce A.V., Peck A.I., Phillimore B.J.C.T., Phillips S., Plumb R.W., Porter K.M., Ramsey Y., Ranby S.A., Rice C.M., Ross M.T., Searle S.M., Sehra H.K., Sheridan E., Skuce C.D., Smith S., Smith M., Spraggon L., Squares S.L., Steward C.A., Sycamore N., Tamlyn-Hall G., Tester J., Theaker A.J., Thomas D.W., Thorpe A., Tracey A., Tromans A., Tubby B., Wall M., Wallis J.M., West A.P., White S.S., Whitehead S.L., Whittaker H., Wild A., Willey D.J., Wilmer T.E., Wood J.M., Wray P.W., Wyatt J.C., Young L., Younger R.M., Bentley D.R., Coulson A., Durbin R.M., Hubbard T., Sulston J.E., Dunham I., Rogers J., Beck S.
    Nature 425:805-811(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  3. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  4. "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].
    Tissue: Brain.
  5. "cDNA cloning of the human homologues of the mouse Ke4 and Ke6 genes at the centromeric end of the human MHC region."
    Ando A., Kikuti Y.Y., Shigenari A., Kawata H., Okamoto N., Shiina T., Chen L., Ikemura T., Abe K., Kimura M., Inoko H.
    Genomics 35:600-602(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 3-261.
  6. "Expression in E. coli and tissue distribution of the human homologue of the mouse Ke 6 gene, 17beta-hydroxysteroid dehydrogenase type 8."
    Ohno S., Nishikawa K., Honda Y., Nakajin S.
    Mol. Cell. Biochem. 309:209-215(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, TISSUE SPECIFICITY.
  7. "17beta-Hydroxysteroid dehydrogenase type 8 and carbonyl reductase type 4 assemble as a ketoacyl reductase of human mitochondrial FAS."
    Chen Z., Kastaniotis A.J., Miinalainen I.J., Rajaram V., Wierenga R.K., Hiltunen J.K.
    FASEB J. 23:3682-3691(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, SUBCELLULAR LOCATION, INTERACTION WITH CBR4.
  8. "Estradiol induces type 8 17beta-hydroxysteroid dehydrogenase expression: crosstalk between estrogen receptor alpha and C/EBPbeta."
    Rotinen M., Celay J., Alonso M.M., Arrazola A., Encio I., Villar J.
    J. Endocrinol. 200:85-92(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: INDUCTION BY ESTRADIOL.
  9. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  10. "An enzyme assisted RP-RPLC approach for in-depth analysis of human liver phosphoproteome."
    Bian Y., Song C., Cheng K., Dong M., Wang F., Huang J., Sun D., Wang L., Ye M., Zou H.
    J. Proteomics 96:253-262(2014) [PubMed] [Europe PMC] [Abstract]
    Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Tissue: Liver.
  11. "Structure of human hydroxysteroid dehydrogenase type 8, HSD17B8."
    Structural genomics consortium (SGC)
    Submitted (FEB-2009) to the PDB data bank
    Cited for: X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF 6-261 IN COMPLEX WITH NAD.
  12. Cited for: VARIANT [LARGE SCALE ANALYSIS] LEU-158.

Entry informationi

Entry nameiDHB8_HUMAN
AccessioniPrimary (citable) accession number: Q92506
Secondary accession number(s): A6NLX7, Q5STP7, Q9UIQ1
Entry historyi
Integrated into UniProtKB/Swiss-Prot: May 30, 2000
Last sequence update: January 24, 2001
Last modified: June 8, 2016
This is version 162 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

Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome

Documents

  1. Human chromosome 6
    Human chromosome 6: 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. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  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.