P0C6K0 (CAPSD_HHBV) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Capsid protein

Alternative name(s):
Core antigen
Core protein
HBcAg

Gene names

Name:

C

Organism

Heron hepatitis B virus (HHBV) [Complete proteome]

Taxonomic identifier

28300 [NCBI]

Taxonomic lineage

Viruses › Retro-transcribing viruses › Hepadnaviridae › Avihepadnavirus

Virus host

Ardeidae (herons) [TaxID: 8899]

Protein attributes

Sequence length	262 AA.
Sequence status	Complete.
Protein existence	Inferred from homology

General annotation (Comments)

Function	Self assembles to form an icosahedral capsid. Most capsid appear to be large particles with a icosahedral symmetry of T=4 and consist of 240 copies of capsid protein, though a fraction forms smaller T=3 particles consisting of 180 capsid proteins. Entering capsid are transported along microtubules to the nucleus. Phosphorylation of the capsid is thought to induce exposure of nuclear localization signal in the C-terminal portion of the capsid protein that allows binding to the nuclear pore complex via the importin (karyopherin-) alpha and beta. Capsids are imported in intact form through the nuclear pore into the nuclear basket, where it probably binds NUP153. Only capsids that contain the mature viral genome can release the viral DNA and capsid protein into the nucleoplasm. Immature capsids get stucked in the basket. Capsids encapsulate the pre-genomic RNA and the P protein. Pre-genomic RNA is reverse transcribed into DNA while the capsid is still in the cytoplasm. The capsid can then either be directed to the nucleus, providing more genome for transcription, or bud through the endoplasmic reticulum to provide new virions By similarity.
Subunit structure	Homodimerizes, then multimerizes By similarity.
Subcellular location	Capsid protein: Virion. Host cytoplasm By similarity.
Sequence similarities	Belongs to the avihepadnavirus core antigen family.

Ontologies

Keywords
Biological process	Cytoplasmic active transport of viral material Host-virus interaction Initiation of viral infection Microtubule-dependent active transport of viral material Viral penetration into host nucleus
Cellular component	Host cytoplasm Virion
Coding sequence diversity	Alternative initiation
Ligand	DNA-binding RNA-binding
Molecular function	Capsid protein T=4 icosahedral capsid protein
PTM	Phosphoprotein
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	interspecies interaction between organisms Inferred from electronic annotation. Source: UniProtKB-KW pathogenesis Inferred from electronic annotation. Source: InterPro
Cellular component	host cell cytoplasm Inferred from electronic annotation. Source: UniProtKB-SubCell viral capsid Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	DNA binding Inferred from electronic annotation. Source: UniProtKB-KW RNA binding Inferred from electronic annotation. Source: UniProtKB-KW 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 Capsid protein (identifier: P0C6K0-1)

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 External core antigen (identifier: P13845-1)

The sequence of this isoform can be found in the external entry P13845.
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
	Chain	1 – 262	262	Capsid protein		PRO_0000324349
Regions
	Region	254 – 260	7	RNA binding By similarity
	Motif	215 – 233	19	Bipartite nuclear localization signal Potential
Amino acid modifications
	Modified residue	232	1	Phosphoserine; by host By similarity
	Modified residue	245	1	Phosphoserine; by host By similarity

Sequences

	Sequence		Length	Mass (Da)
	Isoform Capsid protein [UniParc]. Last modified March 18, 2008. Version 1. Checksum: E9E1EFF7D88C9D1A	FASTA	262	30,191
	10 20 30 40 50 60 MDVNASRALA NVYDLPDDFF PQIDDLVRDA KDALEPYWKA ETIKKHVLIA THFVDLIEDF 70 80 90 100 110 120 WQTTQGMSQI ADALRAVIPP TTVPVPEGFL ITHSEAEEIP LNDLFSNQEE RIVNFQPDYP 130 140 150 160 170 180 ITARIHTHLR VYTKLNEQAL DKARRLLWWH YNCLLWGEAT VTNYISRLRT WLSTPEKYRG 190 200 210 220 230 240 KDAPTIEAIT RPIQVAQGGR NQTKGTRKPR GLEPRRRKVK TTVVYGRRRS KSRGRRSSPS 250 260 QRAGSPLPRN RGNQTRSPSP RE
	Isoform External core antigen [UniParc]. See P13845.		–	–

References

[1]	"Isolation and characterization of a hepatitis B virus endemic in herons." Sprengel R., Kaleta E.F., Will H. J. Virol. 62:3832-3839(1988) [PubMed: 3418788] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].

Cross-references

Sequence databases
EMBL GenBank DDBJ	M22056 Genomic DNA. No translation available.
3D structure databases
ProteinModelPortal	P0C6K0.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR002006. Viral_capsid_core_Hepatitis. [Graphical view]
Pfam	PF00906. Hepatitis_core. 1 hit. [Graphical view]
SUPFAM	SSF47852. Viral_capsid_core_Hepatitis. 1 hit.
ProtoNet	Search...

Entry information

Entry name

CAPSD_HHBV

Accession

Primary (citable) accession number: P0C6K0

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 18, 2008
Last sequence update:	March 18, 2008
Last modified:	September 21, 2011
This is version 20 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program