Reviewed, UniProtKB/Swiss-Prot Q9TTC0 (ENV_KORV)

Names and origin

Protein names

Recommended name:
    Envelope glycoprotein
Alternative name(s):
    Env polyprotein
Cleaved into the following 3 chains:
    1- Recommended name:
            Surface protein
                Short name=SU
        Alternative name(s):
            Glycoprotein 70
              Short name=gp70
    2- Recommended name:
            Transmembrane protein
                Short name=TM
        Alternative name(s):
            Envelope protein p15E
    3- Recommended name:
            R-peptide
        Alternative name(s):
            p2E

Gene names

Name:

env

Organism

Koala retrovirus (KoRV)

Taxonomic identifier

394239 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Retroviridae › Orthoretrovirinae › Gammaretrovirus › unclassified Gammaretrovirus

Virus host

Phascolarctos cinereus (Koala) [TaxID: 38626]

Protein attributes

Sequence length	659 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Inferred 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 proteinBy similarity. Cell membrane; Single-pass type I membrane proteinBy similarity. Surface protein: Virion membrane; Peripheral membrane protein. Cell membrane; Peripheral membrane proteinBy 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: Cell membrane; Peripheral membrane proteinBy 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 an both a circulating virus and an endogenous retrovirus of koala, except in some isolated populations in south Australia.

Ontologies

Keywords
Biological process	Fusion protein
Cellular component	Cell membrane Envelope protein Membrane Virion
Domain	Coiled coil Signal Transmembrane
PTM	Cleavage on pair of basic residues Glycoprotein Lipoprotein Palmitate
Gene Ontology (GO)
None. [Check GOA]

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view
Molecule processing
	Signal peptide	1 – 35	35	Potential
	Chain	36 – 659	624	Envelope glycoprotein
	Chain	36 – 463	428	Surface protein By similarity
	Chain	464 – 659	196	Transmembrane protein By similarity
	Peptide	645 – 659	15	R-peptide By similarity
Regions
	Topological domain	36 – 606	571	Extracellular Potential
	Transmembrane	607 – 627	21	Potential
	Topological domain	628 – 659	32	Cytoplasmic Potential
	Region	466 – 486	21	Fusion peptide By similarity
	Region	533 – 549	17	Immunosuppression By similarity
	Coiled coil	506 – 532	27	Potential
	Coiled coil	567 – 587	21	Potential
	Motif	328 – 331	4	CXXC By similarity
	Motif	550 – 558	9	CX6CC By similarity
	Motif	650 – 653	4	YXXL motif; contains endocytosis signal By similarity
Sites
	Site	463 – 464	2	Cleavage; by host By similarity
	Site	643 – 644	2	Cleavage; by viral protease By similarity
Amino acid modifications
	Lipidation	625	1	S-palmitoyl cysteine; by host By similarity
	Glycosylation	318	1	N-linked (GlcNAc...) Potential
	Glycosylation	389	1	N-linked (GlcNAc...) Potential
	Glycosylation	395	1	N-linked (GlcNAc...) Potential
	Glycosylation	407	1	N-linked (GlcNAc...) Potential
	Glycosylation	427	1	N-linked (GlcNAc...) Potential
	Disulfide bond	141 ↔ 162		By similarity
	Disulfide bond	154 ↔ 167		By similarity
	Disulfide bond	328 ↔ 558		Interchain (between SU and TM chains, or C-357 with C-584); alternate By similarity
	Disulfide bond	328 ↔ 331		Alternate By similarity
	Disulfide bond	550 ↔ 557		By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q9TTC0-1 [UniParc]. Last modified May 1, 2000. Version 1. Checksum: 68B2220DAA6A2ABA	FASTA	659	72,860
	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

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: 10756041] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].

Cross-references

Sequence databases
EMBLGenBankDDBJ	AF151794 Genomic DNA. Translation: AAF15099.1.
3D structure databases
HSSP	HSSP built from PDB template 1MOF based on UniProtKB P03385.
SMR	Q9TTC0. Positions 510-562.
ModBase	Search...
Family and domain databases
InterPro	IPR002050. Env_polyprotein. IPR008981. FMuLV_rcpt_bd. [Graphical view]
Gene3D	G3DSA:3.90.310.10. FMuLV_rcpt_bd. 1 hit.
PANTHER	PTHR10424. Env_polyprotein. 1 hit.
Pfam	PF00429. TLV_coat. 1 hit. [Graphical view]
ProDom	Q9TTC0. [Graphical view] [Entries sharing at least one domain]
BLOCKS	Search...
Other Resources
ProtoNet	Search...

Entry information

Entry name

ENV_KORV

Accession

Primary (citable) accession number: Q9TTC0

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 5, 2006
Last sequence update:	May 1, 2000
Last modified:	September 2, 2008
This is version 39 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Virus (Virus annotation project)