ID   ENV_MCFF3               Reviewed;         640 AA.
AC   P03388; Q85501;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   27-MAR-2024, entry version 124.
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   Mink cell focus-forming murine leukemia virus (isolate CI-3).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus;
OC   Murine leukemia virus.
OX   NCBI_TaxID=11936;
OH   NCBI_TaxID=10090; Mus musculus (Mouse).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Isolate CI-3, and Isolate CI-4;
RX   PubMed=6319752; DOI=10.1128/jvi.49.2.530-539.1984;
RA   Mark G.E., Rapp U.R.;
RT   "Envelope gene sequence of two in vitro-generated mink cell focus-forming
RT   murine leukemia viruses which contain the entire gp70 sequence of the
RT   endogenous nonecotropic parent.";
RL   J. Virol. 49:530-539(1984).
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 virion 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.
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 R-peptide is palmitoylated. {ECO:0000250}.
CC   -!- MISCELLANEOUS: The sequence shown is that of isolate CI-3.
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DR   EMBL; K02725; AAA46375.1; -; Genomic_RNA.
DR   EMBL; K02726; AAA46376.1; -; Genomic_RNA.
DR   SMR; P03388; -.
DR   GlyCosmos; P03388; 6 sites, No reported glycans.
DR   SwissPalm; P03388; -.
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; 2.
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..32
FT                   /evidence="ECO:0000255"
FT   CHAIN           33..640
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000239578"
FT   CHAIN           33..441
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040742"
FT   CHAIN           442..621
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040743"
FT   PEPTIDE         622..640
FT                   /note="R-peptide"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040744"
FT   TOPO_DOM        33..582
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        583..603
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        604..640
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          444..464
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000250"
FT   REGION          510..526
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          473..509
FT                   /evidence="ECO:0000255"
FT   MOTIF           307..310
FT                   /note="CXXC"
FT   MOTIF           527..535
FT                   /note="CX6CC"
FT   MOTIF           627..630
FT                   /note="YXXL motif; contains endocytosis signal"
FT                   /evidence="ECO:0000250"
FT   SITE            441..442
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   SITE            621..622
FT                   /note="Cleavage; by viral protease p14"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        43
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        58
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        297
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        329
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        336
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        369
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        109..126
FT                   /evidence="ECO:0000250"
FT   DISULFID        118..131
FT                   /evidence="ECO:0000250"
FT   DISULFID        307..535
FT                   /note="Interchain (between SU and TM chains, or C-310 with
FT                   C-535); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        307..310
FT                   /evidence="ECO:0000250"
FT   DISULFID        337..391
FT                   /evidence="ECO:0000250"
FT   DISULFID        356..368
FT                   /evidence="ECO:0000250"
FT   DISULFID        398..411
FT                   /evidence="ECO:0000250"
FT   DISULFID        527..534
FT                   /evidence="ECO:0000250"
FT   VARIANT         315..542
FT                   /note="Missing (in strain: Isolate CI-4)"
SQ   SEQUENCE   640 AA;  69726 MW;  C2C71A6749128CF5 CRC64;
     MEGPAFSKPL KDKINPWGPL IILGILIRAG VSVQHDSPHQ VFNVTWRVTN LMTGQTANAT
     SLLGTMTDAF PKLYFDLCDL VGDDWDETGL GCRTPGGRKR ARTFDFYVCP GHTVPTGCGG
     PREGYCGKWG CETTGQAYWK PSSSWDLISL KRGNTPRNQG PCYDSSAVSS DIKGATPGGR
     CNPLVLEFTD AGKKASWDGP KVWGLRLYRS TGTDPVTRFS LTRQVLNIGP RVPIGPNPVI
     TDQLPPSRPV QIMLPRPPQP PPPGAASIVP ETAPPSQQLG TGDRLLNLVN GAYQALNLTS
     PDKTQECWLC LVAGPPYYEG VAVLGTYSNH TSAPANCSVA SQHKLTLSGV AGRGLCIAAF
     PKTHQALCNT TQKTSDGSYH LAAPAGTIWA CNTGLTPCLS TTVLDLTTDY CVLVELWPKV
     TYHSPSYVYG QFEKKKTKYK REPVSLTLAL LLGGLTMGGI AAGVGTGTTA LVATQQFQQL
     QAAMHDDLKE VEKSITNLEK SLTSLSEVVL QNRRGLDLLF LKEGGLCAAL KEECCFYADH
     TGLVRDSMAK LRERLSQRQK LFESQQGWFE GLFNKSPWFT TLISTIMGPL IILLLILLFG
     PWILNRLVQF IKDRISVVQA LVLTQQYHQL KTIGDCKSRE
//