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HAMAP rule MF_04075

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General rule information [?]

Accession MF_04075
Dates 11-MAY-2017 (Created)
29-SEP-2022 (Last updated, Version 6)
Scope(s) Viruses
Template(s) Q76R62 (HBSAG_HBVCJ); [ Recover all ]
Triggered by HAMAP; MF_04075 (Get profile general information and statistics)

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier HBSAG
Protein name RecName: Full=Large envelope protein;
AltName: Full=L glycoprotein;
AltName: Full=L-HBsAg;
AltName: Full=Large S protein;
AltName: Full=Large surface protein;
AltName: Full=Major surface antigen;
Gene name Name=S;

Comments [?]

FUNCTIONThe large envelope protein exists in two topological conformations, one which is termed 'external' or Le-HBsAg and the other 'internal' or Li-HBsAg. In its external conformation the protein attaches the virus to cell receptors and thereby initiating infection. This interaction determines the species specificity and liver tropism. This attachment induces virion internalization predominantly through caveolin-mediated endocytosis. The large envelope protein also assures fusion between virion membrane and endosomal membrane. In its internal conformation the protein plays a role in virion morphogenesis and mediates the contact with the nucleocapsid like a matrix protein.
FUNCTIONThe middle envelope protein plays an important role in the budding of the virion. It is involved in the induction of budding in a nucleocapsid independent way. In this process the majority of envelope proteins bud to form subviral lipoprotein particles of 22 nm of diameter that do not contain a nucleocapsid.
DOMAINThe large envelope protein is synthesized with the pre-S region at the cytosolic side of the endoplasmic reticulum and, hence will be within the virion after budding. Therefore the pre-S region is not N- glycosylated. Later a post-translational translocation of N-terminal pre-S and TM1 domains occur in about 50% of proteins at the virion surface. These molecules change their topology by an unknown mechanism, resulting in exposure of pre-S region at virion surface. For isoform M in contrast, the pre-S2 region is translocated cotranslationally to the endoplasmic reticulum lumen and is N-glycosylated.
PTMIsoform M is N-terminally acetylated by host at a ratio of 90%, and N-glycosylated by host at the pre-S2 region.
SIMILARITYBelongs to the orthohepadnavirus major surface antigen family.

Keywords [?]

Gene Ontology [?]

GO:0016020; Cellular component:membrane
GO:0055036; Cellular component:virion membrane
GO:0039663; Biological process:membrane fusion involved in viral entry into host cell
GO:0019062; Biological process:virion attachment to host cell

Cross-references [?]

Pfam PF00695; vMSA; 1;
General Transmembrane; -; 4;

Features [?]

From: HBSAG_HBVCJ (Q76R62)
Key From To Description Tag Condition FTGroup
INIT_MET Nter Nter /note="Removed; by host" M
CHAIN Nter+1 Cter /note="Large envelope protein"
TOPO_DOM Nter+1 253 /note="Intravirion; in internal conformation"
TOPO_DOM Nter+1 181 /note="Virion surface; in external conformation"
TRANSMEM 182 202 /note="Helical; Name=TM1; Note=In external conformation"
TOPO_DOM 203 253 /note="Intravirion; in external conformation"
TRANSMEM 254 274 /note="Helical; Name=TM2"
TOPO_DOM 275 348 /note="Virion surface"
TRANSMEM 349 369 /note="Helical"
TOPO_DOM 370 375 /note="Intravirion"
TRANSMEM 376 398 /note="Helical; Name=TM3"
TOPO_DOM 399 Cter /note="Virion surface"
REGION Nter+1 174 /note="Pre-S"
REGION Nter+1 119 /note="Pre-S1"
REGION 120 174 /note="Pre-S2"
LIPID Nter+1 Nter+1 /note="N-myristoyl glycine; by host" G

Additional information [?]

Size range 389-431 amino acids
Related rules None
Fusion Nter: None Cter: None

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