P29178 (CAPSD_HBVG1) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Capsid protein

Alternative name(s):
Core antigen
Core protein
HBcAg
p21.5

Gene names

Name:

C

Organism

Hepatitis B virus genotype G subtype adw2 (isolate United States/sf/1990) (HBV-G)

Taxonomic identifier

31515 [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	195 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. Encapsidates hepatitis delta genome By similarity.
Subunit structure	Homodimerizes, then multimerizes. Interacts with cytosol exposed regions of viral L glycoprotein present in the reticulum-to-Golgi compartment. Interacts with human FLNB By similarity.
Subcellular location	Capsid protein: Virion. Host cytoplasm By similarity.
Post-translational modification	Phosphorylated by host SRPK1, SRPK2, and maybe protein kinase C or GAPDH. Phosphorylation is critical for pregenomic RNA packaging. Protein kinase C phosphorylation is stimulated by HBx protein and may play a role in transport of the viral genome to the nucleus at the late step during viral replication cycle By similarity.
Sequence similarities	Belongs to the orthohepadnavirus 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
Domain	Repeat
Ligand	DNA-binding RNA-binding
Molecular function	Capsid protein T=4 icosahedral capsid protein
PTM	Phosphoprotein
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...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 195	195	Capsid protein		PRO_0000222309
Regions
	Repeat	167 – 172	6	1; half-length
	Repeat	174 – 180	7	2
	Repeat	182 – 188	7	3
	Region	167 – 188	22	3 X 7 AA repeats of S-P-R-R-R-[PR]-S
	Region	189 – 195	7	RNA binding By similarity
	Motif	170 – 187	18	Bipartite nuclear localization signal Potential
Amino acid modifications
	Modified residue	167	1	Phosphoserine; by host By similarity
	Modified residue	174	1	Phosphoserine; by host By similarity
	Modified residue	182	1	Phosphoserine; by host By similarity

Sequences

	Sequence		Length	Mass (Da)
	P29178 [UniParc]. Last modified December 1, 1992. Version 1. Checksum: E2B166F879CB7CB7	FASTA	195	22,462
	10 20 30 40 50 60 MDRTTLPYGL FGLDIDPYKE FGATVELLSF LPSDFFPSVR DLLDTASALY RESLESSDHC 70 80 90 100 110 120 SPHHTALRQA ILCWVELMTL ATWVGNNLED PASRDLVVNY VNTNMGLKIR QLLWFHISCL 130 140 150 160 170 180 TFGRETVLEY LVSFGVWIRT PPAYRPPNAP ILSTLPETTV VRRRGRSPRR RTPSPRRRRS 190 PSPRRRRSQS RESQC

References

[1]	"Molecular characterization of a new variant of hepatitis B virus in a persistently infected homosexual man." Bhat R.A., Ulrich P.P., Vyas G.N. Hepatology 11:271-276(1990) [PubMed: 2307406] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
+	Additional computationally mapped references.

Web resources

HepSEQ

Hepatitis virus B database

Cross-references

Sequence databases
PIR	NKVLH3. A37182.
3D structure databases
ProteinModelPortal	P29178.
SMR	P29178. Positions 13-155.
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_HBVG1

Accession

Primary (citable) accession number: P29178

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 1, 1992
Last sequence update:	December 1, 1992
Last modified:	May 31, 2011
This is version 47 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program