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Protein

Potassium voltage-gated channel subfamily A member 5

Gene

Kcna5

Organism
Mus musculus (Mouse)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at transcript leveli

Functioni

Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:8226976, PubMed:11349004). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (By similarity). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation (By similarity). Homotetrameric channels display rapid activation and slow inactivation (PubMed:8226976, PubMed:11349004). May play a role in regulating the secretion of insulin in normal pancreatic islets (By similarity).By similarity2 Publications

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Ion channel, Potassium channel, Voltage-gated channel

Keywords - Biological processi

Ion transport, Potassium transport, Transport

Keywords - Ligandi

Potassium

Enzyme and pathway databases

ReactomeiREACT_287159. Voltage gated Potassium channels.

Names & Taxonomyi

Protein namesi
Recommended name:
Potassium voltage-gated channel subfamily A member 5
Alternative name(s):
Voltage-gated potassium channel subunit Kv1.5
Short name:
KV1-5
Gene namesi
Name:Kcna5
OrganismiMus musculus (Mouse)
Taxonomic identifieri10090 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaSciurognathiMuroideaMuridaeMurinaeMusMus
ProteomesiUP000000589 Componenti: Chromosome 6

Organism-specific databases

MGIiMGI:96662. Kcna5.

Subcellular locationi

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Topological domaini1 – 238238CytoplasmicBy similarityAdd
BLAST
Transmembranei239 – 26022Helical; Name=Segment S1By similarityAdd
BLAST
Topological domaini261 – 31454ExtracellularBy similarityAdd
BLAST
Transmembranei315 – 33622Helical; Name=Segment S2By similarityAdd
BLAST
Topological domaini337 – 34711CytoplasmicBy similarityAdd
BLAST
Transmembranei348 – 36821Helical; Name=Segment S3By similarityAdd
BLAST
Topological domaini369 – 38416ExtracellularBy similarityAdd
BLAST
Transmembranei385 – 40521Helical; Voltage-sensor; Name=Segment S4By similarityAdd
BLAST
Topological domaini406 – 42015CytoplasmicBy similarityAdd
BLAST
Transmembranei421 – 44222Helical; Name=Segment S5By similarityAdd
BLAST
Topological domaini443 – 45614ExtracellularBy similarityAdd
BLAST
Intramembranei457 – 46812Helical; Name=Pore helixBy similarityAdd
BLAST
Intramembranei469 – 4768By similarity
Topological domaini477 – 4837ExtracellularBy similarity
Transmembranei484 – 51229Helical; Name=Segment S6By similarityAdd
BLAST
Topological domaini513 – 60290CytoplasmicBy similarityAdd
BLAST

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Cell membrane, Membrane

Pathology & Biotechi

Disruption phenotypei

No visible phenotype. The action potential in myocytes is not prolonged by low concentrations of 4-aminopyridine, contrary to the situation in wild-type.1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 602602Potassium voltage-gated channel subfamily A member 5PRO_0000053986Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei81 – 811Phosphoserine; by CK2 and PKASequence Analysis
Cross-linki212 – 212Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in SUMO)By similarity
Glycosylationi290 – 2901N-linked (GlcNAc...)Sequence Analysis
Lipidationi337 – 3371S-palmitoyl cysteineSequence Analysis
Cross-linki525 – 525Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in SUMO)By similarity
Modified residuei535 – 5351Phosphoserine; by PKASequence Analysis
Modified residuei546 – 5461Phosphoserine; by PKASequence Analysis
Modified residuei569 – 5691Phosphoserine; by PKASequence Analysis

Post-translational modificationi

Sumoylated on Lys-212, and Lys-525, preferentially with SUMO3. Sumoylation regulates the voltage sensitivity of the channel (By similarity).By similarity

Keywords - PTMi

Glycoprotein, Isopeptide bond, Lipoprotein, Palmitate, Phosphoprotein, Ubl conjugation

Proteomic databases

MaxQBiQ61762.
PaxDbiQ61762.
PRIDEiQ61762.

PTM databases

PhosphoSiteiQ61762.

Expressioni

Tissue specificityi

Highly expressed in heart and moderately in brain. Low levels in thymus, skeletal muscle and spleen. Not expressed in liver, lung or kidney.

Gene expression databases

BgeeiQ61762.
GenevestigatoriQ61762.

Interactioni

Subunit structurei

Homotetramer and heterotetramer of potassium channel proteins. Interacts with DLG1, which enhances channel currents. Forms a ternary complex with DLG1 and CAV3 (By similarity). Interacts with KCNAB1 (By similarity). Interacts with UBE2I (By similarity).By similarity

Protein-protein interaction databases

STRINGi10090.ENSMUSP00000055673.

Structurei

3D structure databases

ProteinModelPortaliQ61762.
SMRiQ61762. Positions 111-516.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni407 – 42014S4-S5 linkerBy similarityAdd
BLAST

Motif

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Motifi469 – 4746Selectivity filterBy similarity
Motifi600 – 6023PDZ-binding

Compositional bias

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Compositional biasi373 – 3764Poly-Gly

Domaini

The amino terminus may be important in determining the rate of inactivation of the channel while the C-terminal PDZ-binding motif may play a role in modulation of channel activity and/or targeting of the channel to specific subcellular compartments.By similarity
The transmembrane segment S4 functions as voltage-sensor and is characterized by a series of positively charged amino acids at every third position. Channel opening and closing is effected by a conformation change that affects the position and orientation of the voltage-sensor paddle formed by S3 and S4 within the membrane. A transmembrane electric field that is positive inside would push the positively charged S4 segment outwards, thereby opening the pore, while a field that is negative inside would pull the S4 segment inwards and close the pore. Changes in the position and orientation of S4 are then transmitted to the activation gate formed by the inner helix bundle via the S4-S5 linker region.By similarity

Sequence similaritiesi

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiCOG1226.
GeneTreeiENSGT00760000118846.
HOGENOMiHOG000231015.
HOVERGENiHBG052230.
InParanoidiQ61762.
KOiK04878.
OMAiGGELQCP.
OrthoDBiEOG7M0NRD.
TreeFamiTF313103.

Family and domain databases

Gene3Di1.20.120.350. 1 hit.
InterProiIPR000210. BTB/POZ-like.
IPR011333. BTB/POZ_fold.
IPR027359. Channel_four-helix_dom.
IPR005821. Ion_trans_dom.
IPR003091. K_chnl.
IPR003968. K_chnl_volt-dep_Kv.
IPR003972. K_chnl_volt-dep_Kv1.
IPR004052. K_chnl_volt-dep_Kv1.5.
IPR003131. T1-type_BTB.
IPR028325. VG_K_chnl.
[Graphical view]
PANTHERiPTHR11537. PTHR11537. 1 hit.
PTHR11537:SF25. PTHR11537:SF25. 1 hit.
PfamiPF02214. BTB_2. 1 hit.
PF00520. Ion_trans. 1 hit.
[Graphical view]
PRINTSiPR00169. KCHANNEL.
PR01512. KV15CHANNEL.
PR01491. KVCHANNEL.
PR01496. SHAKERCHANEL.
SMARTiSM00225. BTB. 1 hit.
[Graphical view]
SUPFAMiSSF54695. SSF54695. 1 hit.

Sequences (3)i

Sequence statusi: Complete.

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

Isoform 1 (identifier: Q61762-1) [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
MEISLVPMEN GSAMTLRGGG EAGASCVQSP RGECGCPPTA GLNNQSKETS
60 70 80 90 100
PRRRATHEDA GQGGRPLPPM PQELPQPRRP SAEDEEGEGD PGLGTVEEDQ
110 120 130 140 150
APQDSGSLHH QRVLINISGL RFETQLGTLA QFPNTLLGDP VKRLRYFDPL
160 170 180 190 200
RNEYFFDRNR PSFDGILYYY QSGGRLRRPV NVSLDVFADE IRFYQLGDEA
210 220 230 240 250
MERFREDEGF IKEEEKPLPR NEFQRQVWLI FEYPESSGSA RAIAIVSVLV
260 270 280 290 300
ILISIITFCL ETLPEFRDER ELLRHPPVPP QPPAPAPGAN GSGSGVLSSG
310 320 330 340 350
PTVAPLLPRT LADPFFIVET TCVIWFTFEL LVRFFACPSK AEFSRNIMNI
360 370 380 390 400
IDIVAIFPYF ITLGTELAEQ QPGGGGQNGQ QAMSLAILRV IRLVRVFRIF
410 420 430 440 450
KLSRHSKGLQ ILGKTLQASM RELGLLIFFL FIGVILFSSA VYFAEADNQG
460 470 480 490 500
SHFSSIPDAF WWAVVTMTTV GYGDMRPITV GGKIVGSLCA IAGVLTIALP
510 520 530 540 550
VPVIVSNFNY FYHRETDHEE QAALKEEQGI QRRESGLDTG GQRKVSCSKA
560 570 580 590 600
SFCKTGGPLE STDSIRRGSC PLEKCHLKAK SNVDLRRSLY ALCLDTSRET

DL
Length:602
Mass (Da):66,580
Last modified:July 27, 2011 - v2
Checksum:i02926E85DC022DDA
GO
Isoform 2 (identifier: Q61762-2) [UniParc]FASTAAdd to basket

Also known as: 5'

The sequence of this isoform differs from the canonical sequence as follows:
     1-200: Missing.

Show »
Length:402
Mass (Da):44,539
Checksum:i6BB846FB2409473D
GO
Isoform 3 (identifier: Q61762-3) [UniParc]FASTAAdd to basket

Also known as: 3'

The sequence of this isoform differs from the canonical sequence as follows:
     515-602: Missing.

Note: Inactive. Inhibits expression of isoform 1 and isoform 2.

Show »
Length:514
Mass (Da):56,871
Checksum:i9A047A2DE9D6DC7B
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti8 – 81M → T in AAA39365 (PubMed:8226976).Curated
Sequence conflicti23 – 231G → V in AAA39365 (PubMed:8226976).Curated
Sequence conflicti61 – 611G → A in AAA39365 (PubMed:8226976).Curated
Sequence conflicti127 – 1271G → D in AAA39365 (PubMed:8226976).Curated
Sequence conflicti130 – 1301A → V in AAA39365 (PubMed:8226976).Curated
Sequence conflicti135 – 1351T → N in AAA39365 (PubMed:8226976).Curated
Sequence conflicti249 – 2491L → S in AAA39365 (PubMed:8226976).Curated
Sequence conflicti268 – 2692DE → VD in AAA39365 (PubMed:8226976).Curated
Sequence conflicti274 – 2741R → L in AAA39365 (PubMed:8226976).Curated
Sequence conflicti289 – 2913ANG → TNA in AAA39365 (PubMed:8226976).Curated
Sequence conflicti301 – 3011P → T in AAA39365 (PubMed:8226976).Curated
Sequence conflicti452 – 4532HF → QL in AAA39365 (PubMed:8226976).Curated
Sequence conflicti553 – 5531C → H in AAA39365 (PubMed:8226976).Curated

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei1 – 200200Missing in isoform 2. 1 PublicationVSP_000961Add
BLAST
Alternative sequencei515 – 60288Missing in isoform 3. 1 PublicationVSP_000962Add
BLAST

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
L22218 mRNA. Translation: AAA39365.1.
AF108659 mRNA. Translation: AAD13779.1.
AF302768 Genomic DNA. Translation: AAG40241.1.
AK146843 mRNA. Translation: BAE27474.1.
CH466523 Genomic DNA. Translation: EDK99840.1.
BC021787 mRNA. Translation: AAH21787.1.
CCDSiCCDS20554.1. [Q61762-1]
PIRiA49507.
RefSeqiNP_666095.1. NM_145983.2. [Q61762-1]
UniGeneiMm.222831.

Genome annotation databases

EnsembliENSMUST00000060972; ENSMUSP00000055673; ENSMUSG00000045534. [Q61762-1]
GeneIDi16493.
KEGGimmu:16493.
UCSCiuc009dva.2. mouse. [Q61762-1]

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
L22218 mRNA. Translation: AAA39365.1.
AF108659 mRNA. Translation: AAD13779.1.
AF302768 Genomic DNA. Translation: AAG40241.1.
AK146843 mRNA. Translation: BAE27474.1.
CH466523 Genomic DNA. Translation: EDK99840.1.
BC021787 mRNA. Translation: AAH21787.1.
CCDSiCCDS20554.1. [Q61762-1]
PIRiA49507.
RefSeqiNP_666095.1. NM_145983.2. [Q61762-1]
UniGeneiMm.222831.

3D structure databases

ProteinModelPortaliQ61762.
SMRiQ61762. Positions 111-516.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi10090.ENSMUSP00000055673.

PTM databases

PhosphoSiteiQ61762.

Proteomic databases

MaxQBiQ61762.
PaxDbiQ61762.
PRIDEiQ61762.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENSMUST00000060972; ENSMUSP00000055673; ENSMUSG00000045534. [Q61762-1]
GeneIDi16493.
KEGGimmu:16493.
UCSCiuc009dva.2. mouse. [Q61762-1]

Organism-specific databases

CTDi3741.
MGIiMGI:96662. Kcna5.

Phylogenomic databases

eggNOGiCOG1226.
GeneTreeiENSGT00760000118846.
HOGENOMiHOG000231015.
HOVERGENiHBG052230.
InParanoidiQ61762.
KOiK04878.
OMAiGGELQCP.
OrthoDBiEOG7M0NRD.
TreeFamiTF313103.

Enzyme and pathway databases

ReactomeiREACT_287159. Voltage gated Potassium channels.

Miscellaneous databases

NextBioi289799.
PROiQ61762.
SOURCEiSearch...

Gene expression databases

BgeeiQ61762.
GenevestigatoriQ61762.

Family and domain databases

Gene3Di1.20.120.350. 1 hit.
InterProiIPR000210. BTB/POZ-like.
IPR011333. BTB/POZ_fold.
IPR027359. Channel_four-helix_dom.
IPR005821. Ion_trans_dom.
IPR003091. K_chnl.
IPR003968. K_chnl_volt-dep_Kv.
IPR003972. K_chnl_volt-dep_Kv1.
IPR004052. K_chnl_volt-dep_Kv1.5.
IPR003131. T1-type_BTB.
IPR028325. VG_K_chnl.
[Graphical view]
PANTHERiPTHR11537. PTHR11537. 1 hit.
PTHR11537:SF25. PTHR11537:SF25. 1 hit.
PfamiPF02214. BTB_2. 1 hit.
PF00520. Ion_trans. 1 hit.
[Graphical view]
PRINTSiPR00169. KCHANNEL.
PR01512. KV15CHANNEL.
PR01491. KVCHANNEL.
PR01496. SHAKERCHANEL.
SMARTiSM00225. BTB. 1 hit.
[Graphical view]
SUPFAMiSSF54695. SSF54695. 1 hit.
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Multiple mRNA isoforms encoding the mouse cardiac Kv1-5 delayed rectifier K+ channel."
    Attali B., Lesage F., Ziliani P., Guillemare E., Honore E., Waldmann R., Hugnot J.-P., Mattei M.-G., Lazdunski M., Barhanin J.
    J. Biol. Chem. 268:24283-24289(1993) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1; 2 AND 3), FUNCTION, SUBCELLULAR LOCATION.
    Strain: Swiss.
    Tissue: Heart.
  2. "Targeted replacement of KV1.5 in the mouse leads to loss of the 4-aminopyridine-sensitive component of I(K,slow) and resistance to drug-induced qt prolongation."
    London B., Guo W., Pan X., Lee J.S., Shusterman V., Rocco C.J., Logothetis D.A., Nerbonne J.M., Hill J.A.
    Circ. Res. 88:940-946(2001) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], DISRUPTION PHENOTYPE, FUNCTION, SUBCELLULAR LOCATION.
    Strain: 129/Sv.
  3. "Cloning and functional expression of mouse heart K+ channel alpha-subunits, Kv1.5, Kv4.2, and Kv4.3."
    Tanaka H., Janzen K., Winkfein R.J., Fiset C., Clark B., Giles W.R.
    Submitted (NOV-1998) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [MRNA].
  4. "The transcriptional landscape of the mammalian genome."
    Carninci P., Kasukawa T., Katayama S., Gough J., Frith M.C., Maeda N., Oyama R., Ravasi T., Lenhard B., Wells C., Kodzius R., Shimokawa K., Bajic V.B., Brenner S.E., Batalov S., Forrest A.R., Zavolan M., Davis M.J.
    , Wilming L.G., Aidinis V., Allen J.E., Ambesi-Impiombato A., Apweiler R., Aturaliya R.N., Bailey T.L., Bansal M., Baxter L., Beisel K.W., Bersano T., Bono H., Chalk A.M., Chiu K.P., Choudhary V., Christoffels A., Clutterbuck D.R., Crowe M.L., Dalla E., Dalrymple B.P., de Bono B., Della Gatta G., di Bernardo D., Down T., Engstrom P., Fagiolini M., Faulkner G., Fletcher C.F., Fukushima T., Furuno M., Futaki S., Gariboldi M., Georgii-Hemming P., Gingeras T.R., Gojobori T., Green R.E., Gustincich S., Harbers M., Hayashi Y., Hensch T.K., Hirokawa N., Hill D., Huminiecki L., Iacono M., Ikeo K., Iwama A., Ishikawa T., Jakt M., Kanapin A., Katoh M., Kawasawa Y., Kelso J., Kitamura H., Kitano H., Kollias G., Krishnan S.P., Kruger A., Kummerfeld S.K., Kurochkin I.V., Lareau L.F., Lazarevic D., Lipovich L., Liu J., Liuni S., McWilliam S., Madan Babu M., Madera M., Marchionni L., Matsuda H., Matsuzawa S., Miki H., Mignone F., Miyake S., Morris K., Mottagui-Tabar S., Mulder N., Nakano N., Nakauchi H., Ng P., Nilsson R., Nishiguchi S., Nishikawa S., Nori F., Ohara O., Okazaki Y., Orlando V., Pang K.C., Pavan W.J., Pavesi G., Pesole G., Petrovsky N., Piazza S., Reed J., Reid J.F., Ring B.Z., Ringwald M., Rost B., Ruan Y., Salzberg S.L., Sandelin A., Schneider C., Schoenbach C., Sekiguchi K., Semple C.A., Seno S., Sessa L., Sheng Y., Shibata Y., Shimada H., Shimada K., Silva D., Sinclair B., Sperling S., Stupka E., Sugiura K., Sultana R., Takenaka Y., Taki K., Tammoja K., Tan S.L., Tang S., Taylor M.S., Tegner J., Teichmann S.A., Ueda H.R., van Nimwegen E., Verardo R., Wei C.L., Yagi K., Yamanishi H., Zabarovsky E., Zhu S., Zimmer A., Hide W., Bult C., Grimmond S.M., Teasdale R.D., Liu E.T., Brusic V., Quackenbush J., Wahlestedt C., Mattick J.S., Hume D.A., Kai C., Sasaki D., Tomaru Y., Fukuda S., Kanamori-Katayama M., Suzuki M., Aoki J., Arakawa T., Iida J., Imamura K., Itoh M., Kato T., Kawaji H., Kawagashira N., Kawashima T., Kojima M., Kondo S., Konno H., Nakano K., Ninomiya N., Nishio T., Okada M., Plessy C., Shibata K., Shiraki T., Suzuki S., Tagami M., Waki K., Watahiki A., Okamura-Oho Y., Suzuki H., Kawai J., Hayashizaki Y.
    Science 309:1559-1563(2005) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
    Strain: C57BL/6J.
    Tissue: Stomach.
  5. Mural R.J., Adams M.D., Myers E.W., Smith H.O., Venter J.C.
    Submitted (JUL-2005) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  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].
    Tissue: Eye.

Entry informationi

Entry nameiKCNA5_MOUSE
AccessioniPrimary (citable) accession number: Q61762
Secondary accession number(s): Q9Z1R6
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: July 27, 2011
Last modified: May 27, 2015
This is version 138 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. MGD cross-references
    Mouse Genome Database (MGD) cross-references in UniProtKB/Swiss-Prot
  2. 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.