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Protein

Very-long-chain enoyl-CoA reductase

Gene

TECR

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

Functioni

Catalyzes the last of the four reactions of the long-chain fatty acids elongation cycle. This endoplasmic reticulum-bound enzymatic process, allows the addition of 2 carbons to the chain of long- and very long-chain fatty acids/VLCFAs per cycle. This enzyme reduces the trans-2,3-enoyl-CoA fatty acid intermediate to an acyl-CoA that can be further elongated by entering a new cycle of elongation. Thereby, it participates to the production of VLCFAs of different chain lengths that are involved in multiple biological processes as precursors of membrane lipids and lipid mediators.1 Publication

Catalytic activityi

A very-long-chain acyl-CoA + NADP+ = a very-long-chain trans-2,3-dehydroacyl-CoA + NADPH.1 Publication

Pathwayi: fatty acid biosynthesis

This protein is involved in the pathway fatty acid biosynthesis, which is part of Lipid metabolism.1 Publication
View all proteins of this organism that are known to be involved in the pathway fatty acid biosynthesis and in Lipid metabolism.

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase

Keywords - Biological processi

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

Keywords - Ligandi

NADP

Enzyme and pathway databases

ReactomeiR-HSA-75876. Synthesis of very long-chain fatty acyl-CoAs.
UniPathwayiUPA00094.

Chemistry

SwissLipidsiSLP:000000436.

Names & Taxonomyi

Protein namesi
Recommended name:
Very-long-chain enoyl-CoA reductaseCurated (EC:1.3.1.931 Publication)
Alternative name(s):
Synaptic glycoprotein SC2
Trans-2,3-enoyl-CoA reductase
Short name:
TER
Gene namesi
Name:TECR
Synonyms:GPSN2, SC2
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 19

Organism-specific databases

HGNCiHGNC:4551. TECR.

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Transmembranei87 – 10721HelicalSequence analysisAdd
BLAST
Transmembranei194 – 21421HelicalSequence analysisAdd
BLAST
Transmembranei255 – 27521HelicalSequence analysisAdd
BLAST

GO - Cellular componenti

  • endoplasmic reticulum Source: HPA
  • endoplasmic reticulum membrane Source: Reactome
  • integral component of endoplasmic reticulum membrane Source: UniProtKB
  • nucleus Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Endoplasmic reticulum, Membrane

Pathology & Biotechi

Involvement in diseasei

Mental retardation, autosomal recessive 14 (MRT14)1 Publication
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionA disorder characterized by significantly below average general intellectual functioning associated with impairments in adaptive behavior and manifested during the developmental period.
See also OMIM:614020
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti182 – 1821P → L in MRT14. 1 Publication
VAR_065918

Keywords - Diseasei

Disease mutation, Mental retardation

Organism-specific databases

MalaCardsiTECR.
MIMi614020. phenotype.
Orphaneti88616. Autosomal recessive non-syndromic intellectual disability.
PharmGKBiPA28946.

Polymorphism and mutation databases

BioMutaiTECR.
DMDMi20177939.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 308308Very-long-chain enoyl-CoA reductasePRO_0000213683Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei22 – 221N6-acetyllysineCombined sources
Modified residuei58 – 581PhosphoserineBy similarity
Modified residuei60 – 601N6-acetyllysineBy similarity
Glycosylationi164 – 1641N-linked (GlcNAc...)Sequence analysis
Glycosylationi247 – 2471N-linked (GlcNAc...)Sequence analysis

Post-translational modificationi

Glycosylated.By similarity

Keywords - PTMi

Acetylation, Glycoprotein, Phosphoprotein

Proteomic databases

EPDiQ9NZ01.
MaxQBiQ9NZ01.
PaxDbiQ9NZ01.
PRIDEiQ9NZ01.

PTM databases

iPTMnetiQ9NZ01.
PhosphoSiteiQ9NZ01.
SwissPalmiQ9NZ01.

Expressioni

Tissue specificityi

Expressed in most tissues tested. Highly expressed in skeletal muscle.1 Publication

Gene expression databases

BgeeiQ9NZ01.
CleanExiHS_GPSN2.
ExpressionAtlasiQ9NZ01. baseline and differential.
GenevisibleiQ9NZ01. HS.

Organism-specific databases

HPAiHPA029780.
HPA056488.

Interactioni

Subunit structurei

Interacts with ELOVL1 and LASS2.1 Publication

Binary interactionsi

WithEntry#Exp.IntActNotes
HACD2Q6Y1H23EBI-2877718,EBI-530257

Protein-protein interaction databases

BioGridi114900. 59 interactions.
IntActiQ9NZ01. 15 interactions.
MINTiMINT-3077000.
STRINGi9606.ENSP00000215567.

Structurei

Secondary structure

1
308
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Beta strandi4 – 1310Combined sources
Beta strandi18 – 236Combined sources
Helixi29 – 3911Combined sources
Beta strandi41 – 433Combined sources
Turni45 – 473Combined sources
Beta strandi50 – 534Combined sources
Turni65 – 673Combined sources
Beta strandi72 – 787Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2DZJNMR-A1-81[»]
ProteinModelPortaliQ9NZ01.
SMRiQ9NZ01. Positions 1-81.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ9NZ01.

Family & Domainsi

Sequence similaritiesi

Belongs to the steroid 5-alpha reductase family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG1639. Eukaryota.
ENOG410XR2S. LUCA.
GeneTreeiENSGT00510000046645.
HOGENOMiHOG000190918.
InParanoidiQ9NZ01.
KOiK10258.
OMAiGPLVIHP.
OrthoDBiEOG7D2FF3.
PhylomeDBiQ9NZ01.
TreeFamiTF300908.

Family and domain databases

InterProiIPR001104. 3-oxo-5_a-steroid_4-DH_C.
IPR029071. Ubiquitin-rel_dom.
[Graphical view]
PfamiPF02544. Steroid_dh. 1 hit.
[Graphical view]
SUPFAMiSSF54236. SSF54236. 1 hit.
PROSITEiPS50244. S5A_REDUCTASE. 1 hit.
[Graphical view]

Sequences (2)i

Sequence statusi: Complete.

This entry describes 2 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: Q9NZ01-1) [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
MKHYEVEILD AKTREKLCFL DKVEPHATIA EIKNLFTKTH PQWYPARQSL
60 70 80 90 100
RLDPKGKSLK DEDVLQKLPV GTTATLYFRD LGAQISWVTV FLTEYAGPLF
110 120 130 140 150
IYLLFYFRVP FIYGHKYDFT SSRHTVVHLA CICHSFHYIK RLLETLFVHR
160 170 180 190 200
FSHGTMPLRN IFKNCTYYWG FAAWMAYYIN HPLYTPPTYG AQQVKLALAI
210 220 230 240 250
FVICQLGNFS IHMALRDLRP AGSKTRKIPY PTKNPFTWLF LLVSCPNYTY
260 270 280 290 300
EVGSWIGFAI MTQCLPVALF SLVGFTQMTI WAKGKHRSYL KEFRDYPPLR

MPIIPFLL
Length:308
Mass (Da):36,034
Last modified:October 1, 2000 - v1
Checksum:i120AD0883820784D
GO
Isoform 2 (identifier: Q9NZ01-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     20-170: Missing.

Show »
Length:157
Mass (Da):18,249
Checksum:i22A7510C68B555E6
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti72 – 754TTAT → PRAH in AAC39872 (PubMed:9653160).Curated
Sequence conflicti248 – 2481Y → C in AAC39872 (PubMed:9653160).Curated
Sequence conflicti248 – 2481Y → C in AAC39873 (PubMed:9653160).Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti182 – 1821P → L in MRT14. 1 Publication
VAR_065918

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei20 – 170151Missing in isoform 2. 1 PublicationVSP_005957Add
BLAST

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AF038958 mRNA. Translation: AAC39872.1.
AF038959 mRNA. Translation: AAC39873.1.
AF222742 mRNA. Translation: AAF32373.1.
AK315412 mRNA. Translation: BAG37802.1.
BT007179 mRNA. Translation: AAP35843.1.
CR456892 mRNA. Translation: CAG33173.1.
BC000174 mRNA. Translation: AAH00174.2.
BC002425 mRNA. Translation: AAH02425.1.
BC005952 mRNA. Translation: AAH05952.1.
BC007801 mRNA. Translation: AAH07801.1.
BC013881 mRNA. Translation: AAH13881.1.
CCDSiCCDS12313.1. [Q9NZ01-1]
PIRiT50638.
T50639.
RefSeqiNP_612510.1. NM_138501.5. [Q9NZ01-1]
UniGeneiHs.515642.

Genome annotation databases

EnsembliENST00000215567; ENSP00000215567; ENSG00000099797. [Q9NZ01-1]
GeneIDi9524.
KEGGihsa:9524.
UCSCiuc002mza.4. human. [Q9NZ01-1]

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AF038958 mRNA. Translation: AAC39872.1.
AF038959 mRNA. Translation: AAC39873.1.
AF222742 mRNA. Translation: AAF32373.1.
AK315412 mRNA. Translation: BAG37802.1.
BT007179 mRNA. Translation: AAP35843.1.
CR456892 mRNA. Translation: CAG33173.1.
BC000174 mRNA. Translation: AAH00174.2.
BC002425 mRNA. Translation: AAH02425.1.
BC005952 mRNA. Translation: AAH05952.1.
BC007801 mRNA. Translation: AAH07801.1.
BC013881 mRNA. Translation: AAH13881.1.
CCDSiCCDS12313.1. [Q9NZ01-1]
PIRiT50638.
T50639.
RefSeqiNP_612510.1. NM_138501.5. [Q9NZ01-1]
UniGeneiHs.515642.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2DZJNMR-A1-81[»]
ProteinModelPortaliQ9NZ01.
SMRiQ9NZ01. Positions 1-81.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi114900. 59 interactions.
IntActiQ9NZ01. 15 interactions.
MINTiMINT-3077000.
STRINGi9606.ENSP00000215567.

Chemistry

SwissLipidsiSLP:000000436.

PTM databases

iPTMnetiQ9NZ01.
PhosphoSiteiQ9NZ01.
SwissPalmiQ9NZ01.

Polymorphism and mutation databases

BioMutaiTECR.
DMDMi20177939.

Proteomic databases

EPDiQ9NZ01.
MaxQBiQ9NZ01.
PaxDbiQ9NZ01.
PRIDEiQ9NZ01.

Protocols and materials databases

DNASUi9524.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000215567; ENSP00000215567; ENSG00000099797. [Q9NZ01-1]
GeneIDi9524.
KEGGihsa:9524.
UCSCiuc002mza.4. human. [Q9NZ01-1]

Organism-specific databases

CTDi9524.
GeneCardsiTECR.
HGNCiHGNC:4551. TECR.
HPAiHPA029780.
HPA056488.
MalaCardsiTECR.
MIMi610057. gene.
614020. phenotype.
neXtProtiNX_Q9NZ01.
Orphaneti88616. Autosomal recessive non-syndromic intellectual disability.
PharmGKBiPA28946.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG1639. Eukaryota.
ENOG410XR2S. LUCA.
GeneTreeiENSGT00510000046645.
HOGENOMiHOG000190918.
InParanoidiQ9NZ01.
KOiK10258.
OMAiGPLVIHP.
OrthoDBiEOG7D2FF3.
PhylomeDBiQ9NZ01.
TreeFamiTF300908.

Enzyme and pathway databases

UniPathwayiUPA00094.
ReactomeiR-HSA-75876. Synthesis of very long-chain fatty acyl-CoAs.

Miscellaneous databases

ChiTaRSiTECR. human.
EvolutionaryTraceiQ9NZ01.
GeneWikiiTECR.
GenomeRNAii9524.
NextBioi35692.
PROiQ9NZ01.
SOURCEiSearch...

Gene expression databases

BgeeiQ9NZ01.
CleanExiHS_GPSN2.
ExpressionAtlasiQ9NZ01. baseline and differential.
GenevisibleiQ9NZ01. HS.

Family and domain databases

InterProiIPR001104. 3-oxo-5_a-steroid_4-DH_C.
IPR029071. Ubiquitin-rel_dom.
[Graphical view]
PfamiPF02544. Steroid_dh. 1 hit.
[Graphical view]
SUPFAMiSSF54236. SSF54236. 1 hit.
PROSITEiPS50244. S5A_REDUCTASE. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Identification of genes expressed in human CD34(+) hematopoietic stem/progenitor cells by expressed sequence tags and efficient full-length cDNA cloning."
    Mao M., Fu G., Wu J.-S., Zhang Q.-H., Zhou J., Kan L.-X., Huang Q.-H., He K.-L., Gu B.-W., Han Z.-G., Shen Y., Gu J., Yu Y.-P., Xu S.-H., Wang Y.-X., Chen S.-J., Chen Z.
    Proc. Natl. Acad. Sci. U.S.A. 95:8175-8180(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS 1 AND 2).
    Tissue: Umbilical cord blood.
  2. "A catalog of genes in human dermal papilla cells as identified by expressed sequence tags."
    Seo H.C., Kim M.K., Kim Y.H., Seo J.M., Lee H.M., Chung H.J., Sohn M.Y., Hwang S.Y., Im S.U., Jung E.J., Kim J.C.
    Submitted (JAN-2000) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1).
    Tissue: Hair follicle dermal papilla.
  3. "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] (ISOFORM 1).
    Tissue: Tongue.
  4. "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 1).
  5. "Cloning of human full open reading frames in Gateway(TM) system entry vector (pDONR201)."
    Ebert L., Schick M., Neubert P., Schatten R., Henze S., Korn B.
    Submitted (JUN-2004) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1).
  6. "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 1).
    Tissue: Brain, Cervix, Ovary and Prostate.
  7. "Identification of two mammalian reductases involved in the two-carbon fatty acyl elongation cascade."
    Moon Y.-A., Horton J.D.
    J. Biol. Chem. 278:7335-7343(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, CATALYTIC ACTIVITY, PATHWAY, SUBCELLULAR LOCATION, TISSUE SPECIFICITY.
  8. "Lysine acetylation targets protein complexes and co-regulates major cellular functions."
    Choudhary C., Kumar C., Gnad F., Nielsen M.L., Rehman M., Walther T.C., Olsen J.V., Mann M.
    Science 325:834-840(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: ACETYLATION [LARGE SCALE ANALYSIS] AT LYS-22, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  9. Cited for: INTERACTION WITH ELOVL1 AND LASS2.
  10. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  11. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  12. "Solution structure of the N-terminal ubiquitin-like domain in human synaptic glycoprotein SC2."
    RIKEN structural genomics initiative (RSGI)
    Submitted (MAR-2007) to the PDB data bank
    Cited for: STRUCTURE BY NMR OF 1-81.
  13. "Exome sequencing reveals a novel mutation for autosomal recessive non-syndromic mental retardation in the TECR gene on chromosome 19p13."
    Caliskan M., Chong J.X., Uricchio L., Anderson R., Chen P., Sougnez C., Garimella K., Gabriel S.B., dePristo M.A., Shakir K., Matern D., Das S., Waggoner D., Nicolae D.L., Ober C.
    Hum. Mol. Genet. 20:1285-1289(2011) [PubMed] [Europe PMC] [Abstract]
    Cited for: VARIANT MRT14 LEU-182.

Entry informationi

Entry nameiTECR_HUMAN
AccessioniPrimary (citable) accession number: Q9NZ01
Secondary accession number(s): B2RD55
, O75350, Q6IBB2, Q9BWK3, Q9Y6P0
Entry historyi
Integrated into UniProtKB/Swiss-Prot: April 16, 2002
Last sequence update: October 1, 2000
Last modified: April 13, 2016
This is version 145 of the entry and version 1 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 19
    Human chromosome 19: 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.