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Q9TTC0 (ENV_KORV) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 70. Feed History...

Clusters with 100%, 90%, 50% identity | Third-party data text xml rdf/xml gff fasta
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Names and origin

Protein namesRecommended name:
Envelope glycoprotein
Alternative name(s):
Env polyprotein

Cleaved into the following 3 chains:

  1. Surface protein
    Short name=SU
    Alternative name(s):
    Glycoprotein 70
    Short name=gp70
  2. Transmembrane protein
    Short name=TM
    Alternative name(s):
    Envelope protein p15E
  3. R-peptide
    Alternative name(s):
    p2E
Gene names
Name:env
OrganismKoala retrovirus (KoRV) [Complete proteome]
Taxonomic identifier394239 [NCBI]
Taxonomic lineageVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeGammaretrovirusunclassified Gammaretrovirus
Virus hostPhascolarctos cinereus (Koala) [TaxID: 38626]

Protein attributes

Sequence length659 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceInferred from homology

General annotation (Comments)

Function

The surface protein (SU) attaches the virus to the host cell by binding to its receptor. This interaction triggers the refolding of the transmembrane protein (TM) and is thought to activate its fusogenic potential by unmasking its fusion peptide. Fusion occurs at the host cell plasma membrane By similarity.

The transmembrane protein (TM) acts as a class I viral fusion protein. Under the current model, the protein has at least 3 conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes. Membranes fusion leads to delivery of the nucleocapsid into the cytoplasm By similarity.

Subunit structure

The mature envelope protein (Env) consists of a trimer of SU-TM heterodimers attached by a labile interchain disulfide bond By similarity.

Subcellular location

Transmembrane protein: Virion membrane; Single-pass type I membrane protein By similarity. Host cell membrane; Single-pass type I membrane protein By similarity.

Surface protein: Virion membrane; Peripheral membrane protein. Host cell membrane; Peripheral membrane protein By similarity. Note: The surface protein is not anchored to the viral envelope, but associates with the extravirion surface through its binding to TM. Both proteins are thought to be concentrated at the site of budding and incorporated into the virions possibly by contacts between the cytoplasmic tail of Env and the N-terminus of Gag By similarity.

R-peptide: Host cell membrane; Peripheral membrane protein By similarity. Note: The R-peptide is membrane-associated through its palmitate By similarity.

Domain

The 17 amino acids long immunosuppressive region is present in many retroviral envelope proteins. Synthetic peptides derived from this relatively conserved sequence inhibit immune function in vitro and in vivo By similarity.

The YXXL motif is involved in determining the exact site of viral release at the surface of infected mononuclear cells and promotes endocytosis By similarity.

Post-translational modification

Specific enzymatic cleavages in vivo yield mature proteins. Envelope glycoproteins are synthesized as a inactive precursor that is N-glycosylated and processed likely by host cell furin or by a furin-like protease in the Golgi to yield the mature SU and TM proteins. The cleavage site between SU and TM requires the minimal sequence [KR]-X-[KR]-R. The R-peptide is released from the C-terminus of the cytoplasmic tail of the TM protein upon particle formation as a result of proteolytic cleavage by the viral protease. Cleavage of this peptide is required for TM to become fusogenic By similarity.

The CXXC motif is highly conserved across a broad range of retroviral envelope proteins. It is thought to participate in the formation of a labile disulfide bond possibly with the CX6CC motif present in the transmembrane protein. Isomerization of the intersubunit disulfide bond to an SU intrachain disulfide bond is thought to occur upon receptor recognition in order to allow membrane fusion By similarity.

The transmembrane protein is palmitoylated By similarity.

The R-peptide is palmitoylated By similarity.

Miscellaneous

Koala retrovirus is both a circulating virus and an endogenous retrovirus of koala, except in some isolated populations in south Australia.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Signal peptide1 – 3535 Potential
Chain36 – 659624Envelope glycoprotein
PRO_0000249423
Chain36 – 463428Surface protein By similarity
PRO_0000249424
Chain464 – 659196Transmembrane protein By similarity
PRO_0000249425
Peptide645 – 65915R-peptide By similarity
PRO_0000249426

Regions

Topological domain36 – 606571Extracellular Potential
Transmembrane607 – 62721Helical; Potential
Topological domain628 – 65932Cytoplasmic Potential
Region466 – 48621Fusion peptide By similarity
Region533 – 54917Immunosuppression By similarity
Coiled coil506 – 53227 Potential
Coiled coil567 – 58721 Potential
Motif328 – 3314CXXC By similarity
Motif550 – 5589CX6CC By similarity
Motif650 – 6534YXXL motif; contains endocytosis signal By similarity

Sites

Site463 – 4642Cleavage; by host By similarity
Site643 – 6442Cleavage; by viral protease By similarity

Amino acid modifications

Lipidation6251S-palmitoyl cysteine; by host By similarity
Glycosylation3181N-linked (GlcNAc...); by host Potential
Glycosylation3891N-linked (GlcNAc...); by host Potential
Glycosylation3951N-linked (GlcNAc...); by host Potential
Glycosylation4071N-linked (GlcNAc...); by host Potential
Glycosylation4271N-linked (GlcNAc...); by host Potential
Disulfide bond141 ↔ 162 By similarity
Disulfide bond154 ↔ 167 By similarity
Disulfide bond328 ↔ 558Interchain (between SU and TM chains, or C-357 with C-584); alternate By similarity
Disulfide bond328 ↔ 331Alternate By similarity
Disulfide bond550 ↔ 557 By similarity

Sequences

Sequence LengthMass (Da)Tools
Q9TTC0 [UniParc].

Last modified May 1, 2000. Version 1.
Checksum: 68B2220DAA6A2ABA

FASTA65972,860
        10         20         30         40         50         60 
MLLISNPRHL GHPMSPGNWK RLIILLSCVF GGAEMNQQHN NPHQPMTLTW QVLSQTGSVV 

        70         80         90        100        110        120 
WEKKAVEPPW TWWPSLEPDV CALVAGLESW DIPELTASAS QQARPPDSNY EHAYNQITWG 

       130        140        150        160        170        180 
TLGCSYPRAR TRIARSQFYV CPRDGRSLSE ARRCGGLESL YCKEWGCETA GTAYWQPRSS 

       190        200        210        220        230        240 
WDLITVGQGH PTGTCERTGW CNPLKIEFTE PGKRFRNWLQ GRTWGLRFYV TGHPGVQLTI 

       250        260        270        280        290        300 
RLVITSPPPV VVGPDPVLAE QGPPRKIPFL PRVPVPTLSP PASPIPTVQA SPPAPSTPSP 

       310        320        330        340        350        360 
TTGDRLFGLV QGAFLALNAT NPEATESCWL CLALGPPYYE GIATPGQVTY ASTDSQCRWG 

       370        380        390        400        410        420 
GKGKLTLTEV SGLGLCIGKV PPTHQHLCNL TIPLNASHTH KYLLPSNRSW WACNSGLTPC 

       430        440        450        460        470        480 
LSTSVFNQSN DFCIQIQLVP RIYYHPDGTL LQAYESPHSR NKREPVSLTL AVLLGLGVAA 

       490        500        510        520        530        540 
GIGTGSTALI KGPIDLQQGL TSLQIAMDTD LRALQDSISK LEDSLTSLSE VVLQNRRGLD 

       550        560        570        580        590        600 
LLFLKEGGLC AALKEECCFY VDHSGAVRDS MRRLKERLDK RQLEHQKNLS WYEGWFNRSP 

       610        620        630        640        650 
WLTTLLSALA GPLLLLLLLL TLGPCVINKL VQFINDRVSA VRILVLRHKY QTLDNEDNL 

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References

[1]"The nucleotide sequence of koala (Phascolarctos cinereus) retrovirus: a novel type C endogenous virus related to Gibbon ape leukemia virus."
Hanger J.J., Bromham L.D., McKee J.J., O'Brien T.M., Robinson W.F.
J. Virol. 74:4264-4272(2000) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AF151794 Genomic DNA. Translation: AAF15099.1.

3D structure databases

ProteinModelPortalQ9TTC0.
SMRQ9TTC0. Positions 510-562.
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

Gene3D3.90.310.10. 1 hit.
InterProIPR008981. FMuLV_rcpt-bd.
IPR018154. TLV/ENV_coat_polyprotein.
[Graphical view]
PANTHERPTHR10424. PTHR10424. 1 hit.
PfamPF00429. TLV_coat. 1 hit.
[Graphical view]
SUPFAMSSF49830. SSF49830. 1 hit.
ProtoNetSearch...

Entry information

Entry nameENV_KORV
AccessionPrimary (citable) accession number: Q9TTC0
Entry history
Integrated into UniProtKB/Swiss-Prot: September 5, 2006
Last sequence update: May 1, 2000
Last modified: February 19, 2014
This is version 70 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program