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Protein

Large envelope protein

Gene

S

Organism
Hepatitis B virus genotype D subtype adw (isolate United Kingdom/adyw/1979) (HBV-D)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli

Functioni

The 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.UniRule annotation
The 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.UniRule annotation

GO - Biological processi

Keywordsi

Biological processCaveolin-mediated endocytosis of virus by host, Fusion of virus membrane with host endosomal membrane, Fusion of virus membrane with host membrane, Host-virus interaction, Viral attachment to host cell, Viral penetration into host cytoplasm, Virus endocytosis by host, Virus entry into host cell

Names & Taxonomyi

Protein namesi
Recommended name:
Large envelope proteinUniRule annotation
Alternative name(s):
L glycoproteinUniRule annotation
L-HBsAgUniRule annotation
Short name:
LHBUniRule annotation
Large S proteinUniRule annotation
Large surface proteinUniRule annotation
Major surface antigenUniRule annotation
Gene namesi
Name:SUniRule annotation
OrganismiHepatitis B virus genotype D subtype adw (isolate United Kingdom/adyw/1979) (HBV-D)
Taxonomic identifieri10419 [NCBI]
Taxonomic lineageiVirusesRetro-transcribing virusesHepadnaviridaeOrthohepadnavirus
Virus hostiHomo sapiens (Human) [TaxID: 9606]
Pan troglodytes (Chimpanzee) [TaxID: 9598]

Subcellular locationi

  • Virion membrane UniRule annotation

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini2 – 242Intravirion; in internal conformationUniRule annotationAdd BLAST241
Topological domaini2 – 170Virion surface; in external conformationUniRule annotationAdd BLAST169
Transmembranei171 – 191Helical; Name=TM1; Note=In external conformationUniRule annotationAdd BLAST21
Topological domaini192 – 242Intravirion; in external conformationUniRule annotationAdd BLAST51
Transmembranei243 – 263Helical; Name=TM2UniRule annotationAdd BLAST21
Topological domaini264 – 337Virion surfaceUniRule annotationAdd BLAST74
Transmembranei338 – 358HelicalUniRule annotationAdd BLAST21
Topological domaini359 – 364IntravirionUniRule annotation6
Transmembranei365 – 387Helical; Name=TM3UniRule annotationAdd BLAST23
Topological domaini388 – 389Virion surfaceUniRule annotation2

GO - Cellular componenti

Keywords - Cellular componenti

Membrane, Virion

Pathology & Biotechi

Biotechnological usei

Systematic vaccination of individuals at risk of exposure to the virus has been the main method of controlling the morbidity and mortality associated with hepatitis B. The first hepatitis B vaccine was manufactured by the purification and inactivation of HBsAg obtained from the plasma of chronic hepatitis B virus carriers. The vaccine is now produced by recombinant DNA techniques and expression of the S isoform in yeast cells. The pre-S region do not seem to induce strong enough antigenic response.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved; by hostUniRule annotation
ChainiPRO_00000381092 – 389Large envelope proteinUniRule annotationAdd BLAST388

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Lipidationi2N-myristoyl glycine; by hostUniRule annotation1
Glycosylationi309N-linked (GlcNAc...) asparagine; by hostUniRule annotation1
Isoform M (identifier: P03139-2)
Modified residuei1N-acetylmethionineBy similarity1

Post-translational modificationi

Isoform M is N-terminally acetylated by host at a ratio of 90%, and N-glycosylated by host at the pre-S2 region.UniRule annotationBy similarity
Myristoylated.UniRule annotation

Keywords - PTMi

Acetylation, Glycoprotein, Lipoprotein, Myristate

Interactioni

Subunit structurei

Li-HBsAg interacts with capsid protein and with HDV Large delta antigen. Isoform M associates with host chaperone CANX through its pre-S2 N glycan. This association may be essential for M proper secretion.UniRule annotation

Protein-protein interaction databases

DIPiDIP-61744N.

Structurei

3D structure databases

SMRiP03139.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni2 – 163Pre-SUniRule annotationAdd BLAST162
Regioni2 – 108Pre-S1UniRule annotationAdd BLAST107
Regioni109 – 163Pre-S2UniRule annotationAdd BLAST55

Domaini

The 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.UniRule annotation

Sequence similaritiesi

Belongs to the orthohepadnavirus major surface antigen family.UniRule annotation

Keywords - Domaini

Transmembrane, Transmembrane helix

Family and domain databases

HAMAPiMF_04075. HBV_HBSAG. 1 hit.
InterProiView protein in InterPro
IPR000349. Hepvir_surfAg.
PfamiView protein in Pfam
PF00695. vMSA. 1 hit.

Sequences (3)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 3 isoformsi produced by alternative splicing and alternative initiation. AlignAdd to basket

Isoform L (identifier: P03139-1) [UniParc]FASTAAdd to basket
Also known as: Large envelope protein, LHB, L-HBsAg

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MGQNLSTSNP LGFFPDHQLD PAFRANTNNP DWDFNPNKDT WPDANKVGAG
60 70 80 90 100
AFGLGFTPPH GGLLGWSPQA QGIMQTLPAN PPPASTNRQS GRQPTPLSPP
110 120 130 140 150
LRTTHPQAMH WNSTTFHQTL QDPRVRGLYF PAGGSSSGTV NPVPTTTSPI
160 170 180 190 200
SSIFSRIGDP ALNMENITSG FLGPLLVLQA GFFLLTRILT IPQSLDSWWT
210 220 230 240 250
SLNFLGGTTV CLGQNSQSPI SNHSPTSCPP TCPGYRWMCL RRFIIFLFIL
260 270 280 290 300
LLCLIFLLVL LDYQGMLPVC PLIPGSSTTS TGSCRTCTTP AQGISMYPSC
310 320 330 340 350
CCTKPSDGNC TCIPIPSSWA FGKFLWEWAS ARFSWLSLLV PFVQWFVGLS
360 370 380
PIVWLSVIWM MWYWGPSLYS ILSPFLPLLP IFFCLWAYI
Length:389
Mass (Da):42,801
Last modified:January 23, 2007 - v3
Checksum:i1069EF6B4679A669
GO
Isoform M (identifier: P03139-2) [UniParc]FASTAAdd to basket
Also known as: Middle envelope protein, MHB, M-HBsAg

The sequence of this isoform differs from the canonical sequence as follows:
     1-108: Missing.

Show »
Length:281
Mass (Da):31,270
Checksum:iA497A6508AD253C9
GO
Isoform S (identifier: P03139-3) [UniParc]FASTAAdd to basket
Also known as: Small envelope protein, SHB, S-HBsAg

The sequence of this isoform differs from the canonical sequence as follows:
     1-163: Missing.

Show »
Length:226
Mass (Da):25,385
Checksum:i4A921ED8CB60EB78
GO

Sequence cautioni

The sequence AAA45487 differs from that shown. Reason: Erroneous initiation.Curated

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_0314001 – 163Missing in isoform S. CuratedAdd BLAST163
Alternative sequenceiVSP_0314011 – 108Missing in isoform M. CuratedAdd BLAST108

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
J02202 Genomic RNA. Translation: AAA45487.1. Different initiation.
PIRiA93217. SAVLAJ.

Keywords - Coding sequence diversityi

Alternative initiation, Alternative splicing

Similar proteinsi

Entry informationi

Entry nameiHBSAG_HBVD1
AccessioniPrimary (citable) accession number: P03139
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: January 23, 2007
Last modified: July 5, 2017
This is version 77 of the entry and version 3 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Miscellaneousi

Documents

  1. SIMILARITY comments
    Index of protein domains and families