ID   ENV_AVISN               Reviewed;         567 AA.
AC   P31796;
DT   01-JUL-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-JUL-1993, sequence version 1.
DT   27-MAR-2024, entry version 102.
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 spleen necrosis virus.
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Gammaretrovirus;
OC   Avian reticuloendotheliosis virus.
OX   NCBI_TaxID=11899;
OH   NCBI_TaxID=8976; Galliformes.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=Clone PPB101;
RX   PubMed=1313915; DOI=10.1128/jvi.66.5.3026-3031.1992;
RA   Kewalramani V.N., Panganiban A.T., Emerman M.;
RT   "Spleen necrosis virus, an avian immunosuppressive retrovirus, shares a
RT   receptor with the type D simian retroviruses.";
RL   J. Virol. 66:3026-3031(1992).
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}.
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DR   EMBL; M87666; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   PIR; A38212; VCFVAS.
DR   SMR; P31796; -.
DR   GlyCosmos; P31796; 8 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   InterPro; IPR018154; TLV/ENV_coat_polyprotein.
DR   PANTHER; PTHR10424:SF75; ENDOGENOUS RETROVIRUS GROUP S71 MEMBER 1 ENV POLYPROTEIN-RELATED; 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..567
FT                   /note="Envelope glycoprotein"
FT                   /id="PRO_0000239547"
FT   CHAIN           36..398
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040685"
FT   CHAIN           399..567
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000040686"
FT   TOPO_DOM        36..525
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        526..546
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        547..567
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          402..422
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000255"
FT   REGION          462..478
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          423..473
FT                   /evidence="ECO:0000255"
FT   COILED          483..519
FT                   /evidence="ECO:0000255"
FT   MOTIF           255..258
FT                   /note="CXXC"
FT   MOTIF           479..487
FT                   /note="CX6CC"
FT   SITE            398..399
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   LIPID           549
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        245
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        274
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        280
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        306
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        319
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        328
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        335
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        491
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        255..487
FT                   /note="Interchain (between SU and TM chains, or C-258 with
FT                   C-487); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        255..258
FT                   /evidence="ECO:0000250"
FT   DISULFID        479..486
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   567 AA;  61597 MW;  204EA57C32159175 CRC64;
     MDCLTNLRSA EGKVDQASKI LILLVAWWGF GTTAEGYPLQ QLWELPCDCS GGYVSSIPTY
     YTYSLDCGGS TAYLTYGSGT GSWSWGGGFK QQWECVFKPK IIPSVQGQPG PCPSECLQIA
     TQMHSTCYEK TQECTLLGKT YFTAILQKTK LGSYEDGPNK LIQASCTGTV GKPVCWDPVA
     PVYVSDGGGP TDMIREESVR ERLEEIIRHS YPSVQYHPLA LPRSRGVDLD PQTSDILEAT
     HQVLNATNPK LAENCWLCMT LGTPIPAAIP TNGNVTLDGN CSLSLPFGCN PPGSIDVSCY
     AGEADNRTGI PVGYVHFTNC TSIQEVTNET SQMGNLTRLC PPPGHVFVCG NNMAYTALPN
     KWIGLCILAS IVPDISIISG EEPIPLPSIE YTARRHKRAV QFIPLLVGLG ISGATLAGGT
     GLGVSVHTYH KLSNQLIEDV QALSGTINDL QDQIDSLAEV VLQNRRGLDL LTAEQGGICL
     ALQEKCCFYA NKSGIVRDKI RKLQEDLIER KRALYDNPLW SGLNGFLPYL LPLLGPLFGL
     ILFLTLGPCI MKTLTRIIHD KIQAVKS
//