P03147 (CAPSD_HBVD1) 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 D subtype adw (isolate United Kingdom/adyw/1979) (HBV-D)

Taxonomic identifier

10419 [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	183 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

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. Ref.3 Encapsidates hepatitis delta genome By similarity. Ref.3
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 A, 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. Protein kinase A phosphorylation may promote capsid assembly 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
Technical term	3D-structure
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 – 183

183

Capsid protein

PRO_0000222318

Regions

Repeat

155 – 161

7

1; half-length

Repeat

162 – 169

8

2

Repeat

170 – 177

8

3

Region

155 – 177

23

3 X 8 AA repeats of S-P-R-R-R-[PR]-S-Q

Region

177 – 183

7

RNA binding By similarity

Motif

158 – 175

18

Bipartite nuclear localization signal Potential

Amino acid modifications

Modified residue

87

1

Phosphoserine; by host PKA By similarity

Modified residue

155

1

Phosphoserine; by host By similarity

Modified residue

162

1

Phosphoserine; by host By similarity

Modified residue

170

1

Phosphoserine; by host By similarity

Experimental info

Mutagenesis

97

1

F → L: Enhances capsid assembly. Ref.6

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

183

Helix Strand Turn

Details...

Helix

7 – 9

3

Helix

13 – 16

4

Helix

27 – 33

7

Helix

35 – 38

4

Helix

39 – 41

3

Beta strand

43 – 45

3

Helix

50 – 74

25

Helix

79 – 85

7

Turn

86 – 91

6

Helix

92 – 110

19

Helix

112 – 126

15

Helix

130 – 132

3

Sequences

	Sequence		Length	Mass (Da)
	P03147 [UniParc]. Last modified July 21, 1986. Version 1. Checksum: 545ED0E55527F26C	FASTA	183	21,042
	10 20 30 40 50 60 MDIDPYKEFG ATVELLSFLP SDFFPSVRDL LDTAAALYRD ALESPEHCSP HHTALRQAIL 70 80 90 100 110 120 CWGDLMTLAT WVGTNLEDPA SRDLVVSYVN TNVGLKFRQL LWFHISCLTF GRETVLEYLV 130 140 150 160 170 180 SFGVWIRTPP AYRPPNAPIL STLPETTVVR RRGRSPRRRT PSPRRRRSQS PRRRRSQSRE SQC

References

[1]	"Hepatitis B virus genes and their expression in E. coli." Pasek M., Goto T., Gilbert W., Zink B., Schaller H., McKay P., Leadbetter G., Murray K. Nature 282:575-579(1979) [PubMed: 399329] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[2]	"Hepatitis B virus core antigen: synthesis in Escherichia coli and application in diagnosis." Stahl S., MacKay P., Magazin M., Bruce S.A., Murray K. Proc. Natl. Acad. Sci. U.S.A. 79:1606-1610(1982) [PubMed: 7041126] [Abstract] Cited for: CHARACTERIZATION.
[3]	"Hepatitis core antigen produced in Escherichia coli: subunit composition, conformational analysis, and in vitro capsid assembly." Wingfield P.T., Stahl S.J., Williams R.W., Steven A.C. Biochemistry 34:4919-4932(1995) [PubMed: 7711014] [Abstract] Cited for: FUNCTION.
[4]	"The morphogenic linker peptide of HBV capsid protein forms a mobile array on the interior surface." Watts N.R., Conway J.F., Cheng N., Stahl S.J., Belnap D.M., Steven A.C., Wingfield P.T. EMBO J. 21:876-884(2002) [PubMed: 11867516] [Abstract] Cited for: CAPSID MORPHOGENESIS.
[5]	"Weak protein-protein interactions are sufficient to drive assembly of hepatitis B virus capsids." Ceres P., Zlotnick A. Biochemistry 41:11525-11531(2002) [PubMed: 12269796] [Abstract] Cited for: CAPSID ASSEMBLY.
[6]	"Hepatitis B virus capsid assembly is enhanced by naturally occurring mutation F97L." Ceres P., Stray S.J., Zlotnick A. J. Virol. 78:9538-9543(2004) [PubMed: 15308745] [Abstract] Cited for: MUTAGENESIS OF PHE-97.
[7]	"Global structural changes in hepatitis B virus capsids induced by the assembly effector HAP1." Bourne C.R., Finn M.G., Zlotnick A. J. Virol. 80:11055-11061(2006) [PubMed: 16943288] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (3.96 ANGSTROMS) OF 0-149.
+	Additional computationally mapped references.

Web resources

HepSEQ

Hepatitis virus B database

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

J02202 Genomic RNA. Translation: AAA45486.1.

PIR

NKVLA2. B93217.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2G33	X-ray	3.96	A/B/C/D	1-149	[»]
2G34	X-ray	5.05	A/B/C/D	1-149	[»]
2QIJ	X-ray	8.90	A/B/C/D	3-148	[»]
3KXS	X-ray	2.25	A/B/C/D/E/F	1-143	[»]

ProteinModelPortal

P03147.

SMR

P03147. Positions 3-143.

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_HBVD1

Accession

Primary (citable) accession number: P03147

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 21, 1986
Last modified:	May 31, 2011
This is version 66 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program