ID   ENV_FSVSM               Reviewed;         645 AA.
AC   P21445;
DT   01-MAY-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 2.
DT   27-MAR-2024, entry version 108.
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   Feline sarcoma virus (strain SM) (Sm-FeSV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus;
OC   Feline leukemia virus.
OX   NCBI_TaxID=11779;
OH   NCBI_TaxID=9681; Felidae (cat family).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2823466; DOI=10.1016/0042-6822(87)90194-2;
RA   Guilhot S., Hampe A., D'Auriol L., Galibert F.;
RT   "Nucleotide sequence analysis of the LTRs and env genes of SM-FeSV and GA-
RT   FeSV.";
RL   Virology 161:252-258(1987).
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   -!- 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}.
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DR   EMBL; M23025; AAA74004.1; -; Genomic_DNA.
DR   PIR; A33741; VCMVSS.
DR   SMR; P21445; -.
DR   GlyCosmos; P21445; 10 sites, No reported glycans.
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..36
FT                   /evidence="ECO:0000255"
FT   CHAIN           37..645
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000239572"
FT   CHAIN           37..448
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040727"
FT   CHAIN           449..628
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040728"
FT   PEPTIDE         629..645
FT                   /note="R-peptide"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000239573"
FT   TOPO_DOM        37..589
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        590..610
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        611..645
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          238..283
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          451..471
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000255"
FT   REGION          517..533
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          479..528
FT                   /evidence="ECO:0000255"
FT   COILED          538..574
FT                   /evidence="ECO:0000255"
FT   MOTIF           315..318
FT                   /note="CXXC"
FT   MOTIF           534..542
FT                   /note="CX6CC"
FT   COMPBIAS        249..279
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            448..449
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   SITE            628..629
FT                   /note="Cleavage; by viral protease"
FT                   /evidence="ECO:0000250"
FT   LIPID           609
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        46
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        61
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        270
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        305
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        310
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        334
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        337
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        377
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        393
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        413
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        128..150
FT                   /evidence="ECO:0000250"
FT   DISULFID        142..155
FT                   /evidence="ECO:0000250"
FT   DISULFID        315..542
FT                   /note="Interchain (between SU and TM chains, or C-318 with
FT                   C-542); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        315..318
FT                   /evidence="ECO:0000250"
FT   DISULFID        534..541
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   645 AA;  71594 MW;  4E6DB90A00A43B21 CRC64;
     MEGPTHPKPF KDKTFSWDLI ILVGVVRVLL RLDVGMANPS PHQVYNVTWV ITNVQTNSQA
     NATSMLGTLT DAYPTLHVDL CDLVGDTWEP IVLDPSNVKH GARYSSSKYG CKTTDRKKQQ
     QTYPFYVCPG HAPSMGPKGT HCGGAHDGFC AAWGCETTGE AWWKPTSSWD YITVKRGSSQ
     DTSCDKNCNP LVLQFTQKGR QASWDGPKLW GLRLYRTGYD PIALFSVSRQ VSTIMPPQAM
     GPNLVLPEQK PPSRQSQTKS KVATQKPQTN GTTPRSVAPA TMSPKRIGTR DRLINLVQGT
     YLALNATDPN KTKDCWLCLV SRPPYYEGIA ILGNYSNQTN PPPSCLSTPQ HKLTISEVSG
     QGLCIGTVPR THQALCNKTQ QGHTGAHYLA APNGTYWACN TGLTPCISMA VLNWTSDFCV
     LIELWPRVTY HQPEYIYTHF DKAVRFRREP ISLTVALMLG GLTVGGIAAG VGTGTKALLE
     TAQFRQLQIA MHTDIQALEE SISALEKSLT SLSEVVLQNR RGLDILFLQG GGLCAALKEE
     CCFYADHTGL VRDNMAKLRE RLKQRQQLFD SQQGWFEGWF NKSPWFTTLI SSIMGPLLIL
     LLILLFGPCI LNRLVQFVKD RISVVQALIL TQQYQQIQQY DPDRP
//