ID   ENV_KORV                Reviewed;         659 AA.
AC   Q9TTC0;
DT   05-SEP-2006, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   27-MAR-2024, entry version 94.
DE   RecName: Full=Envelope glycoprotein;
DE   AltName: Full=Env polyprotein;
DE   Contains:
DE     RecName: Full=Surface protein;
DE              Short=SU;
DE     AltName: Full=Glycoprotein 70;
DE              Short=gp70;
DE   Contains:
DE     RecName: Full=Transmembrane protein;
DE              Short=TM;
DE     AltName: Full=Envelope protein p15E;
DE   Contains:
DE     RecName: Full=R-peptide;
DE     AltName: Full=p2E;
DE   Flags: Precursor;
GN   Name=env;
OS   Koala retrovirus (KoRV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus.
OX   NCBI_TaxID=394239;
OH   NCBI_TaxID=38626; Phascolarctos cinereus (Koala).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=10756041; DOI=10.1128/jvi.74.9.4264-4272.2000;
RA   Hanger J.J., Bromham L.D., McKee J.J., O'Brien T.M., Robinson W.F.;
RT   "The nucleotide sequence of koala (Phascolarctos cinereus) retrovirus: a
RT   novel type C endogenous virus related to Gibbon ape leukemia virus.";
RL   J. Virol. 74:4264-4272(2000).
CC   -!- FUNCTION: The surface protein (SU) attaches the virus to the host cell
CC       by binding to its receptor. This interaction triggers the refolding of
CC       the transmembrane protein (TM) and is thought to activate its fusogenic
CC       potential by unmasking its fusion peptide. Fusion occurs at the host
CC       cell plasma membrane (By similarity). {ECO:0000250}.
CC   -!- FUNCTION: The transmembrane protein (TM) acts as a class I viral fusion
CC       protein. Under the current model, the protein has at least 3
CC       conformational states: pre-fusion native state, pre-hairpin
CC       intermediate state, and post-fusion hairpin state. During viral and
CC       target cell membrane fusion, the coiled coil regions (heptad repeats)
CC       assume a trimer-of-hairpins structure, positioning the fusion peptide
CC       in close proximity to the C-terminal region of the ectodomain. The
CC       formation of this structure appears to drive apposition and subsequent
CC       fusion of viral and target cell membranes. Membranes fusion leads to
CC       delivery of the nucleocapsid into the cytoplasm (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBUNIT: The mature envelope protein (Env) consists of a trimer of SU-
CC       TM heterodimers attached by a labile interchain disulfide bond.
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Transmembrane protein]: Virion membrane
CC       {ECO:0000250}; Single-pass type I membrane protein {ECO:0000250}. Host
CC       cell membrane {ECO:0000250}; Single-pass type I membrane protein
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Surface protein]: Virion membrane; Peripheral
CC       membrane protein. Host cell membrane {ECO:0000250}; Peripheral membrane
CC       protein {ECO:0000250}. Note=The surface protein is not anchored to the
CC       viral envelope, but associates with the extravirion surface through its
CC       binding to TM. Both proteins are thought to be concentrated at the site
CC       of budding and incorporated into the virions possibly by contacts
CC       between the cytoplasmic tail of Env and the N-terminus of Gag (By
CC       similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [R-peptide]: Host cell membrane {ECO:0000250};
CC       Peripheral membrane protein {ECO:0000250}. Note=The R-peptide is
CC       membrane-associated through its palmitate. {ECO:0000250}.
CC   -!- DOMAIN: The 17 amino acids long immunosuppressive region is present in
CC       many retroviral envelope proteins. Synthetic peptides derived from this
CC       relatively conserved sequence inhibit immune function in vitro and in
CC       vivo (By similarity). {ECO:0000250}.
CC   -!- DOMAIN: The YXXL motif is involved in determining the exact site of
CC       viral release at the surface of infected mononuclear cells and promotes
CC       endocytosis. {ECO:0000250}.
CC   -!- PTM: Specific enzymatic cleavages in vivo yield mature proteins.
CC       Envelope glycoproteins are synthesized as an inactive precursor that is
CC       N-glycosylated and processed likely by host cell furin or by a furin-
CC       like protease in the Golgi to yield the mature SU and TM proteins. The
CC       cleavage site between SU and TM requires the minimal sequence [KR]-X-
CC       [KR]-R. The R-peptide is released from the C-terminus of the
CC       cytoplasmic tail of the TM protein upon particle formation as a result
CC       of proteolytic cleavage by the viral protease. Cleavage of this peptide
CC       is required for TM to become fusogenic (By similarity). {ECO:0000250}.
CC   -!- PTM: The CXXC motif is highly conserved across a broad range of
CC       retroviral envelope proteins. It is thought to participate in the
CC       formation of a labile disulfide bond possibly with the CX6CC motif
CC       present in the transmembrane protein. Isomerization of the intersubunit
CC       disulfide bond to an SU intrachain disulfide bond is thought to occur
CC       upon receptor recognition in order to allow membrane fusion (By
CC       similarity). {ECO:0000250}.
CC   -!- PTM: The transmembrane protein is palmitoylated. {ECO:0000250}.
CC   -!- PTM: The R-peptide is palmitoylated. {ECO:0000250}.
CC   -!- MISCELLANEOUS: Koala retrovirus is both a circulating virus and an
CC       endogenous retrovirus of koala, except in some isolated populations in
CC       south Australia.
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DR   EMBL; AF151794; AAF15099.1; -; Genomic_DNA.
DR   SMR; Q9TTC0; -.
DR   GlyCosmos; Q9TTC0; 5 sites, No reported glycans.
DR   OrthoDB; 1612at10239; -.
DR   Proteomes; UP000007765; Genome.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR   GO; GO:0019031; C:viral envelope; IEA:UniProtKB-KW.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0019064; P:fusion of virus membrane with host plasma membrane; IEA:UniProtKB-KW.
DR   GO; GO:0046718; P:viral entry into host cell; IEA:UniProtKB-KW.
DR   GO; GO:0019062; P:virion attachment to host cell; IEA:UniProtKB-KW.
DR   CDD; cd09851; HTLV-1-like_HR1-HR2; 1.
DR   Gene3D; 1.10.287.210; -; 1.
DR   Gene3D; 3.90.310.10; ENV polyprotein, receptor-binding domain; 1.
DR   InterPro; IPR008981; FMuLV_rcpt-bd.
DR   InterPro; IPR018154; TLV/ENV_coat_polyprotein.
DR   PANTHER; PTHR10424:SF77; BC035947 PROTEIN-RELATED; 1.
DR   PANTHER; PTHR10424; VIRAL ENVELOPE PROTEIN; 1.
DR   Pfam; PF00429; TLV_coat; 1.
DR   SUPFAM; SSF49830; ENV polyprotein, receptor-binding domain; 1.
DR   SUPFAM; SSF58069; Virus ectodomain; 1.
PE   3: Inferred from homology;
KW   Cleavage on pair of basic residues; Coiled coil; Disulfide bond;
KW   Fusion of virus membrane with host cell membrane;
KW   Fusion of virus membrane with host membrane; Glycoprotein;
KW   Host cell membrane; Host membrane; Host-virus interaction; Lipoprotein;
KW   Membrane; Palmitate; Signal; Transmembrane; Transmembrane helix;
KW   Viral attachment to host cell; Viral envelope protein;
KW   Viral penetration into host cytoplasm; Virion; Virus entry into host cell.
FT   SIGNAL          1..35
FT                   /evidence="ECO:0000255"
FT   CHAIN           36..659
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000249423"
FT   CHAIN           36..463
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000249424"
FT   CHAIN           464..659
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000249425"
FT   PEPTIDE         645..659
FT                   /note="R-peptide"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000249426"
FT   TOPO_DOM        36..606
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        607..627
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        628..659
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          278..301
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          466..486
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000250"
FT   REGION          533..549
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          506..532
FT                   /evidence="ECO:0000255"
FT   COILED          567..587
FT                   /evidence="ECO:0000255"
FT   MOTIF           328..331
FT                   /note="CXXC"
FT                   /evidence="ECO:0000250"
FT   MOTIF           550..558
FT                   /note="CX6CC"
FT                   /evidence="ECO:0000250"
FT   MOTIF           650..653
FT                   /note="YXXL motif; contains endocytosis signal"
FT                   /evidence="ECO:0000250"
FT   COMPBIAS        278..299
FT                   /note="Pro residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            463..464
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   SITE            643..644
FT                   /note="Cleavage; by viral protease"
FT                   /evidence="ECO:0000250"
FT   LIPID           625
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        318
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        389
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        395
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        407
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        427
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        141..162
FT                   /evidence="ECO:0000250"
FT   DISULFID        154..167
FT                   /evidence="ECO:0000250"
FT   DISULFID        328..558
FT                   /note="Interchain (between SU and TM chains, or C-357 with
FT                   C-584); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        328..331
FT                   /evidence="ECO:0000250"
FT   DISULFID        550..557
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   659 AA;  72860 MW;  68B2220DAA6A2ABA CRC64;
     MLLISNPRHL GHPMSPGNWK RLIILLSCVF GGAEMNQQHN NPHQPMTLTW QVLSQTGSVV
     WEKKAVEPPW TWWPSLEPDV CALVAGLESW DIPELTASAS QQARPPDSNY EHAYNQITWG
     TLGCSYPRAR TRIARSQFYV CPRDGRSLSE ARRCGGLESL YCKEWGCETA GTAYWQPRSS
     WDLITVGQGH PTGTCERTGW CNPLKIEFTE PGKRFRNWLQ GRTWGLRFYV TGHPGVQLTI
     RLVITSPPPV VVGPDPVLAE QGPPRKIPFL PRVPVPTLSP PASPIPTVQA SPPAPSTPSP
     TTGDRLFGLV QGAFLALNAT NPEATESCWL CLALGPPYYE GIATPGQVTY ASTDSQCRWG
     GKGKLTLTEV SGLGLCIGKV PPTHQHLCNL TIPLNASHTH KYLLPSNRSW WACNSGLTPC
     LSTSVFNQSN DFCIQIQLVP RIYYHPDGTL LQAYESPHSR NKREPVSLTL AVLLGLGVAA
     GIGTGSTALI KGPIDLQQGL TSLQIAMDTD LRALQDSISK LEDSLTSLSE VVLQNRRGLD
     LLFLKEGGLC AALKEECCFY VDHSGAVRDS MRRLKERLDK RQLEHQKNLS WYEGWFNRSP
     WLTTLLSALA GPLLLLLLLL TLGPCVINKL VQFINDRVSA VRILVLRHKY QTLDNEDNL
//