ID   ENV_FLVLB               Reviewed;         662 AA.
AC   P11261; Q85515; Q85516; Q85517;
DT   01-JUL-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-JUL-1989, 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   Feline leukemia virus (strain B/lambda-B1).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus;
OC   Feline leukemia virus.
OX   NCBI_TaxID=103916;
OH   NCBI_TaxID=9685; Felis catus (Cat) (Felis silvestris catus).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=2444714; DOI=10.1128/jvi.61.11.3410-3415.1987;
RA   Nicolaisen-Strouss K., Kumar H.P.M., Fitting T., Grant C.K., Elder J.H.;
RT   "Natural feline leukemia virus variant escapes neutralization by a
RT   monoclonal antibody via an amino acid change outside the antibody-binding
RT   epitope.";
RL   J. Virol. 61:3410-3415(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; J03448; AAA43048.1; -; Genomic_RNA.
DR   PIR; A27172; VCMVLB.
DR   PDB; 1LCS; X-ray; 2.50 A; A/B=35-245.
DR   PDBsum; 1LCS; -.
DR   SMR; P11261; -.
DR   GlyCosmos; P11261; 8 sites, No reported glycans.
DR   EvolutionaryTrace; P11261; -.
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   1: Evidence at protein level;
KW   3D-structure; Cleavage on pair of basic residues; Coiled coil;
KW   Disulfide bond; 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..34
FT                   /evidence="ECO:0000255"
FT   CHAIN           35..662
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000239566"
FT   CHAIN           35..465
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040714"
FT   CHAIN           466..645
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040715"
FT   PEPTIDE         646..662
FT                   /note="R-peptide"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000239567"
FT   TOPO_DOM        35..606
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        607..627
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        628..662
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          251..281
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          468..488
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000255"
FT   REGION          534..550
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          496..545
FT                   /evidence="ECO:0000255"
FT   COILED          555..591
FT                   /evidence="ECO:0000255"
FT   MOTIF           332..335
FT                   /note="CXXC"
FT   MOTIF           551..559
FT                   /note="CX6CC"
FT   COMPBIAS        255..281
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            465..466
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   SITE            645..646
FT                   /note="Cleavage; by viral protease"
FT                   /evidence="ECO:0000250"
FT   LIPID           626
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        43
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        58
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        286
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        322
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        327
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        351
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        354
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        430
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        115..132
FT                   /evidence="ECO:0000250"
FT   DISULFID        124..137
FT                   /evidence="ECO:0000250"
FT   DISULFID        332..559
FT                   /note="Interchain (between SU and TM chains, or C-335 with
FT                   C-559); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        332..335
FT                   /evidence="ECO:0000250"
FT   DISULFID        551..558
FT                   /evidence="ECO:0000250"
FT   STRAND          42..50
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   TURN            51..53
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          56..64
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   TURN            66..68
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          73..76
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           77..79
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          98..100
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           101..108
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          112..119
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           122..124
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           127..129
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          140..143
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          150..158
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          168..174
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   TURN            179..181
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           190..192
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          196..201
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   HELIX           203..207
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          214..220
FT                   /evidence="ECO:0007829|PDB:1LCS"
FT   STRAND          228..238
FT                   /evidence="ECO:0007829|PDB:1LCS"
SQ   SEQUENCE   662 AA;  73132 MW;  D4AC18E197230575 CRC64;
     MEGPTHPKPS KDKTFSWDLM ILVGVLLRLD VGMANPSPHQ IYNVTWTITN LVTGTKANAT
     SMLGTLTDAF PTMYFDLCDI IGNTWNPSDQ EPFPGYGCDQ PMRRWQQRNT PFYVCPGHAN
     RKQCGGPQDG FCAVWGCETT GETYWRPTSS WDYITVKKGV TQGIYQCSGG GWCGPCYDKA
     VHSSITGASE GGRCNPLILQ FTQKGRQTSW DGPKSWGLRL YRSGYDPIAL FSVSRQVMTI
     TLPQAMGPNL VLPDQKPPSR QSQIESRVTP HHSQGNGGTP GITLVNASIA PLSTPVTPAS
     PKRIGTGNRL INLVQGTYLA LNVTNPNKTK DCWLCLVSRP PYYEGIAVLG NYSNQTNPPP
     SCLSDPQHKL TISEVSGQGS CIGTVPKTHQ ALCKKTQKGH KGTHYLAAPS GTYWACNTGL
     TPCISMAVLN WTSDFCVLIE LWPRVTYHQP EYVYTHFDKT VRLRREPISL TVALMLGGLT
     VGGIAAGVGT GTKALLETAQ FGQLQMAMHT DIQALEESIS ALEKSLTSLS EVVLQNRRGL
     DILFLQEGGL CAALKEECCF YADHTGLVRD NMAKLRERLK QRQQLFDSQQ GWFEGWFNKS
     PWFTTLISSI MGPLLILLLI LLFGPCILNR LVQFVKDRIS VVQALILTQQ YQQIKQYDPD
     QP
//