Reviewed, UniProtKB/Swiss-Prot P0C625 (HBEAG_HBVA3)

Names and origin

Protein names

Recommended name:
    External core antigen
Alternative name(s):
    HBeAg
    Precore protein
    p25

Gene names

Name:

C

Organism

Hepatitis B virus genotype A2 subtype adw2 (strain Rutter 1979) (HBV-A) [Complete proteome]

Taxonomic identifier

480116 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Hepadnaviridae › Orthohepadnavirus

Virus host

Pan troglodytes (Chimpanzee) [TaxID: 9598]
Homo sapiens (Human) [TaxID: 9606]

Protein attributes

Sequence length	214 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	May regulate immune response to the intracellular capsid in acting as a T cell tolerogen, by having an immunoregulatory effect which prevents destruction of infected cells by cytotoxic T cells. This immune regulation may predispose to chronicity during perinatal infections and prevent severe liver injury during adult infections By similarity.
Subunit structure	Homodimerizes.
Subcellular location	Secreted. Host nucleus.
Post-translational modification	Phosphorylated. Cleaved by host furin By similarity.
Sequence similarities	Belongs to the orthohepadnavirus precore antigen family.

Ontologies

Keywords
Biological process	Viral immunoevasion
Cellular component	Nucleus Secreted
Coding sequence diversity	Alternative initiation
Domain	Repeat Signal
PTM	Disulfide bond
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	evasion by virus of host immune response Inferred from electronic annotation. Source: UniProtKB-KW pathogenesis Inferred from electronic annotation. Source: InterPro
Cellular component	host cell nucleus Inferred from electronic annotation. Source: UniProtKB-SubCell nucleus Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	structural molecule activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Alternative products

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

Isoform External core antigen (identifier: P0C625-1)

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 Capsid protein (identifier: P03148-1)

The sequence of this isoform can be found in the external entry P03148-1.
Isoforms of the same protein are often annotated in two different entries if their sequences differ significantly.

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 19	19	Potential
	Chain	20 – 185	166	External core antigen		PRO_0000315013
	Propeptide	186 – 214	29	By similarity		PRO_0000314869
Regions
	Repeat	186 – 192	7	1; half-length
	Repeat	193 – 200	8	2
	Repeat	201 – 208	8	3
	Region	186 – 208	23	3 X 8 AA repeats of S-P-R-R-R-R-S-[PQ]
Sites
	Site	185 – 186	2	Cleavage; by host By similarity
Amino acid modifications
	Disulfide bond	77		Interchain By similarity
	Disulfide bond	90		Interchain By similarity
Natural variations
	Natural variant	122	1	V → M
	Natural variant	126	1	I → L Frequent mutation in chronic HBV carriers. Ref.4
	Natural variant	198	1	R → P

Sequences

	Sequence		Length	Mass (Da)
	Isoform External core antigen [UniParc]. Last modified January 15, 2008. Version 1. Checksum: 56438263E63B46F6	FASTA	214	24,580
	10 20 30 40 50 60 MQLFHLCLII SCTCPTVQAS KLCLGWLWGM DIDPYKEFGA TVELLSFLPS DFFPSVRDLL 70 80 90 100 110 120 DTASALYREA LESPEHCSPH HTALRQAILC WGELMTLATW VGNNLEDPAS RDLVVNYVNT 130 140 150 160 170 180 NVGLKIRQLL WFHISCLTFG RETVLEYLVS FGVWIRTPPA YRPPNAPILS TLPETTVVRR 190 200 210 RDRGRSPRRR TPSPRRRRSP SPRRRRSQSR ESQC
	Isoform Capsid protein. See P03148.	FASTA	–	–

References

[1]	"The nucleotide sequence of the hepatitis B viral genome and the identification of the major viral genes." Valenzuela P., Quiroga M., Zaldivar J., Gray P., Rutter W.J. (In) Field B.N., Jaenisch R., Fox C.F. (eds.); Animal virus genetics, pp.57-70, Academic Press, New York (1980) Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Proteaselike sequence in hepatitis B virus core antigen is not required for e antigen generation and may not be part of an aspartic acid-type protease." Nassal M., Galle P.R., Schaller H. J. Virol. 63:2598-2604(1989) [PubMed: 2657101] [Abstract] Cited for: CLEAVAGE BY HOST.
[3]	"Transport of hepatitis B virus precore protein into the nucleus after cleavage of its signal peptide." Ou J.H., Yeh C.T., Yen T.S. J. Virol. 63:5238-5243(1989) [PubMed: 2585603] [Abstract] Cited for: NUCLEAR LOCALIZATION.
[4]	"Subtype-independent immature secretion and subtype-dependent replication deficiency of a highly frequent, naturally occurring mutation of human hepatitis B virus core antigen." Yuan T.T., Tai P.C., Shih C. J. Virol. 73:10122-10128(1999) [PubMed: 10559327] [Abstract] Cited for: VARIANT LEU-126.

Web resources

HepSEQ

Hepatitis virus B database

Cross-references

Sequence databases
EMBLGenBankDDBJ	X02763 Genomic DNA. No translation available.
3D structure databases
ModBase	Search...
Family and domain databases
InterPro	IPR013195. Vir_capsid_Znf-put_N_Hepatitis. IPR002006. Viral_capsid_core_Hepatitis. [Graphical view]
Pfam	PF08290. Hep_core_N. 1 hit. PF00906. Hepatitis_core. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

HBEAG_HBVA3

Accession

Primary (citable) accession number: P0C625

Entry history

Integrated into UniProtKB/Swiss-Prot:	January 15, 2008
Last sequence update:	January 15, 2008
Last modified:	June 16, 2009
This is version 9 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

Virus (Virus annotation project)