P03145 (HBSAG_DHBV1) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Large envelope protein

Alternative name(s):
L glycoprotein
L-HBsAg
Short name=LHB
Large S protein
Large surface protein
Major surface antigen

Cleaved into the following chain:

1. Truncated S protein
   Short name=St

Gene names

Name:

S

Organism

Duck hepatitis B virus (strain United States/DHBV-16) (DHBV) [Complete proteome]

Taxonomic identifier

489543 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Hepadnaviridae › Avihepadnavirus

Virus host

Anas (ducks) [TaxID: 8835]

Protein attributes

Sequence length	328 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	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. The large envelope protein probably also assumes fusion between virion and host membranes. In its internal conformation the protein plays a role in virion morphogenesis and mediates the contact with the nucleocapsid like a matrix protein By similarity. Truncated S protein may be involved in translocation of pre-S domain through the virion membrane.
Subunit structure	Large internal envelope protein interacts with capsid protein By similarity.
Subcellular location	Virion membrane.
Domain	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.
Post-translational modification	Myristoylation contributes importantly to DHBV infectivity. It is most likely required for an early step of the life cycle involving the entry or uncoating of virus particles. Phosphorylated on pre-S domain for about 50% of L proteins, the L chains with internal pre-S region (Li-HBsAg). Ref.4 Ref.5 Isoform S may be cleaved by a cellular protease to produce truncated S protein.
Sequence similarities	Belongs to the avihepadnavirus major surface antigen family.

Ontologies

Keywords
Biological process	Fusion of virus membrane with host membrane Host-virus interaction Initiation of viral infection Viral attachment to host cell Viral penetration into host cytoplasm
Cellular component	Membrane Virion
Coding sequence diversity	Alternative initiation
Domain	Transmembrane Transmembrane helix
PTM	Glycoprotein Lipoprotein Myristate Phosphoprotein
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	interspecies interaction between organisms Inferred from electronic annotation. Source: UniProtKB-KW viral reproduction Inferred from electronic annotation. Source: InterPro
Cellular component	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW virion membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
Complete GO annotation...

Alternative products

This entry describes 2 isoforms produced by alternative initiation. [Align] [Select]

Isoform L (identifier: P03145-1)

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.

Isoform S (identifier: P03145-2)

Also known as: Small envelope protein; SHB; S-HBsAg;

The sequence of this isoform differs from the canonical sequence as follows:
     1-161: Missing.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Initiator methionine	1	1	Removed; by host By similarity
	Chain	2 – 328	327	Large envelope protein		PRO_0000038075
	Chain	162 – ?238	77	Truncated S protein		PRO_0000322196
Regions
	Topological domain	2 – 236	235	Cytoplasmic; in internal conformation Potential
	Topological domain	2 – 163	162	Extracellular; in external conformation Potential
	Transmembrane	164 – 184	21	Helical; Name=TM1; Note=In external conformation; Potential
	Topological domain	185 – 236	52	Cytoplasmic; in external conformation Potential
	Transmembrane	237 – 257	21	Helical; Name=TM2; Potential
	Topological domain	258 – 282	25	Extracellular Potential
	Transmembrane	283 – 303	21	Helical; Name=TM3; Potential
	Topological domain	304 – 328	25	Cytoplasmic Potential
	Region	2 – 161	160	Pre-S
Sites
	Site	?238 – ?239	2	Cleavage; by host Potential
Amino acid modifications
	Lipidation	2	1	N-myristoyl glycine; by host Ref.3
	Glycosylation	260	1	N-linked (GlcNAc...); by host Potential
Natural variations
	Alternative sequence	1 – 161	161	Missing in isoform S.		VSP_031887
Experimental info
	Mutagenesis	118	1	S → A: 64% loss of phosphorylation. Ref.5
	Mutagenesis	185 – 188	4	KILE → AILA: Complete loss of pre-S domain translocation. Ref.6

Sequences

	Sequence		Length	Mass (Da)
	Isoform L (Large envelope protein) (LHB) (L-HBsAg) [UniParc]. Last modified January 23, 2007. Version 4. Checksum: B2D771241E407456	FASTA	328	36,230
	10 20 30 40 50 60 MGQHPAKSMD VRRIEGGEIL LNQLAGRMIP KGTLTWSGKF PTLDHVLDHV QTMEEINTLQ 70 80 90 100 110 120 NQGAWPAGAG RRVGLSNPTP QEIPQPQWTP EEDQKAREAF RRYQEERPPE TTTIPPSSPP 130 140 150 160 170 180 QWKLQPGDDP LLGNQSLLET HPLYQSEPAV PVIKTPPLKK KMSGTFGGIL AGLIGLLVSF 190 200 210 220 230 240 FLLIKILEIL RRLDWWWISL SSPKGKMQCA FQDTGAQISP HYVGSCPWGC PGFLWTYLRL 250 260 270 280 290 300 FIIFLLILLV AAGLLYLTDN GSTILGKLQW ASVSALFSSI SSLLPSDPKS LVALTFGLSL 310 320 IWMTSSSATQ TLVTLTQLAT LSALFYKS
	Isoform S (Small envelope protein) (SHB) (S-HBsAg) [UniParc]. Checksum: CA3AB8C59BCF1973	FASTA	167	18,202
	10 20 30 40 50 60 MSGTFGGILA GLIGLLVSFF LLIKILEILR RLDWWWISLS SPKGKMQCAF QDTGAQISPH 70 80 90 100 110 120 YVGSCPWGCP GFLWTYLRLF IIFLLILLVA AGLLYLTDNG STILGKLQWA SVSALFSSIS 130 140 150 160 SLLPSDPKSL VALTFGLSLI WMTSSSATQT LVTLTQLATL SALFYKS

References

[1]	"Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison with woodchuck and human hepatitis B virus sequences." Mandart E., Kay A., Galibert F. J. Virol. 49:782-792(1984) [PubMed: 6699938] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Complete nucleotide sequence of a German duck hepatitis B virus." Mattes F., Tong S., Teubner K., Blum H.E. Nucleic Acids Res. 18:6140-6140(1990) [PubMed: 2235507] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: Isolate DHBV F1-6.
[3]	"Myristylation of a duck hepatitis B virus envelope protein is essential for infectivity but not for virus assembly." Macrae D.R., Bruss V., Ganem D. Virology 181:359-363(1991) [PubMed: 1994583] [Abstract] Cited for: MYRISTOYLATION AT GLY-2.
[4]	"The large surface protein of duck hepatitis B virus is phosphorylated in the pre-S domain." Grgacic E.V., Anderson D.A. J. Virol. 68:7344-7350(1994) [PubMed: 7933117] [Abstract] Cited for: PHOSPHORYLATION.
[5]	"Normal phosphorylation of duck hepatitis B virus L protein is dispensable for infectivity." Grgacic E.V., Lin B., Gazina E.V., Snooks M.J., Anderson D.A. J. Gen. Virol. 79:2743-2751(1998) [PubMed: 9820150] [Abstract] Cited for: PHOSPHORYLATION AT SER-118, MUTAGENESIS OF SER-118.
[6]	"Identification of structural determinants of the first transmembrane domain of the small envelope protein of duck hepatitis B virus essential for particle morphogenesis." Grgacic E.V. J. Gen. Virol. 83:1635-1644(2002) [PubMed: 12075081] [Abstract] Cited for: MUTAGENESIS OF 185-LYS--GLU-188.
[7]	"St, a truncated envelope protein derived from the S protein of duck hepatitis B virus, acts as a chaperone for the folding of the large envelope protein." Grgacic E.V., Anderson D.A. J. Virol. 79:5346-5352(2005) [PubMed: 15827149] [Abstract] Cited for: CHARACTERIZATION OF TRUNCATED S PROTEIN.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X12798 Genomic DNA. Translation: CAB57224.1.
3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR000349. Hepvir_surfAg. [Graphical view]
Pfam	PF00695. vMSA. 2 hits. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

HBSAG_DHBV1

Accession

Primary (citable) accession number: P03145

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	January 23, 2007
Last modified:	May 31, 2011
This is version 71 of the entry and version 4 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program