ID   ENV_AVIRE               Reviewed;         582 AA.
AC   P03399;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   28-JAN-2026, entry version 109.
DE   RecName: Full=Envelope glycoprotein;
DE   AltName: Full=Env polyprotein;
DE   Contains:
DE     RecName: Full=Surface protein;
DE              Short=SU;
DE     AltName: Full=Glycoprotein 73;
DE              Short=gp73;
DE   Contains:
DE     RecName: Full=Transmembrane protein;
DE              Short=TM;
DE     AltName: Full=Glycoprotein 22;
DE              Short=gp22;
DE   Flags: Precursor;
GN   Name=env;
OS   Avian reticuloendotheliosis virus.
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus;
OC   Gammaretrovirus aviretend.
OX   NCBI_TaxID=11636;
OH   NCBI_TaxID=8976; Galliformes.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=A;
RX   PubMed=6090694; DOI=10.1128/jvi.52.1.172-182.1984;
RA   Wilhelmsen K.C., Eggleton K., Temin H.M.;
RT   "Nucleic acid sequences of the oncogene v-rel in reticuloendotheliosis
RT   virus strain T and its cellular homolog, the proto-oncogene c-rel.";
RL   J. Virol. 52:172-182(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}. Note=It is probably concentrated at the site of budding
CC       and incorporated into the virions possibly by contacts between the
CC       cytoplasmic tail of Env and the N-terminus of Gag. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Surface protein]: Virion membrane {ECO:0000250};
CC       Peripheral membrane protein {ECO:0000250}. Host cell membrane
CC       {ECO:0000250}; Peripheral membrane protein {ECO:0000250}. Note=The
CC       surface protein is not anchored to the viral envelope, but associates
CC       with the extravirion surface through its binding to TM. It is probably
CC       concentrated at the site of budding and incorporated into the virions
CC       possibly by contacts between the cytoplasmic tail of Env and the N-
CC       terminus of Gag (By similarity). {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 (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   -!- MISCELLANEOUS: Strain A is a helper virus of the strain T.
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DR   EMBL; X01455; CAA25686.1; -; Genomic_RNA.
DR   PIR; A03999; VCVDAR.
DR   SMR; P03399; -.
DR   GlyCosmos; P03399; 4 sites, No reported glycans.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
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:symbiont 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   InterPro; IPR018154; TLV/ENV_coat_polyprotein.
DR   PANTHER; PTHR10424:SF75; ENDOGENOUS RETROVIRUS GROUP S71 MEMBER 1 ENV POLYPROTEIN; 1.
DR   PANTHER; PTHR10424; VIRAL ENVELOPE PROTEIN; 1.
DR   Pfam; PF00429; TLV_coat; 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..582
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000239546"
FT   CHAIN           36..392
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040683"
FT   CHAIN           393..582
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040684"
FT   TOPO_DOM        36..519
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        520..540
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        541..582
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          396..416
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000255"
FT   REGION          456..472
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   REGION          562..582
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COILED          417..467
FT                   /evidence="ECO:0000255"
FT   COILED          477..513
FT                   /evidence="ECO:0000255"
FT   MOTIF           251..254
FT                   /note="CXXC"
FT   MOTIF           473..481
FT                   /note="CX6CC"
FT   COMPBIAS        562..572
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            392..393
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   LIPID           543
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        241
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        301
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        314
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        485
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        251..481
FT                   /note="Interchain (between SU and TM chains, or C-254 with
FT                   C-481); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        251..254
FT                   /evidence="ECO:0000250"
FT   DISULFID        473..480
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   582 AA;  64138 MW;  CD2560ADFC026D32 CRC64;
     MDCLTDLRST EGKVDQAGKT LILLVVWWGF GTTAEGHPLQ QLWELPCDCS GGYVSPDLPI
     TPTPSIAVAS PLPDLRVWLQ GSWGWGGGFR QQWECVFKPK IIPSVQEQPG PCECLTIATQ
     MHSTCYEKAQ ECTLLGKTYF TAILQKTKLG SYEDGPNKLL QASCTGIWET SMLGPRCPCV
     CLDGGGPTDR FGRICAEGLE EIIRHSYPSV QYHPLALPRP RGVDLDPQTS DILEATHQVL
     NATNPQLAEN CWLCMTLGTQ SPQPSRRMAM SLSMEIAVLA SLSGATHRVN RCQLLCREAD
     NRTGIPVGYV HFTNCTSIQE SLTRRVIYEI LRDYVLHRVM YLCVEQHAYT ALPNKWIGLC
     ILASIVPDMS IIPGEEPIPL PSIEYTAGRH KRAVQFIPLL VGLGITGATL AGGTGLGVSV
     HTYHKLSNQL IEDVQALSGT INDLQDQIDS LAEVVLQNRR GLDLLTAEQG GICLALQEKC
     CFYANKSGIV RDKIRKLQED LLARKRALYD NPLWNGLNGF LPYLLPSLGP LFGLILFLTL
     GPCIRKTLTR IIHDKIQGSK NPRISPAVQA TPNRDGYPRS MV
//