ID   CAPSD_HPBDC             Reviewed;         262 AA.
AC   P0C6K1;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   18-MAR-2008, sequence version 1.
DT   29-SEP-2021, entry version 53.
DE   RecName: Full=Capsid protein;
DE   AltName: Full=Core antigen;
DE   AltName: Full=Core protein;
DE   AltName: Full=HBcAg;
GN   Name=C;
OS   Duck hepatitis B virus (strain China) (DHBV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Blubervirales; Hepadnaviridae; Avihepadnavirus.
OX   NCBI_TaxID=31510;
OH   NCBI_TaxID=8835; Anas (ducks).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2235506; DOI=10.1093/nar/18.20.6139;
RA   Tong S., Mattes F., Teubner K., Blum H.E.;
RT   "Complete nucleotide sequence of a Chinese duck hepatitis B virus.";
RL   Nucleic Acids Res. 18:6139-6139(1990).
CC   -!- FUNCTION: Self assembles to form an icosahedral capsid. Most capsid
CC       appear to be large particles with an icosahedral symmetry of T=4 and
CC       consist of 240 copies of capsid protein, though a fraction forms
CC       smaller T=3 particles consisting of 180 capsid proteins. Entering
CC       capsid are transported along microtubules to the nucleus.
CC       Phosphorylation of the capsid is thought to induce exposure of nuclear
CC       localization signal in the C-terminal portion of the capsid protein
CC       that allows binding to the nuclear pore complex via the importin
CC       (karyopherin-) alpha and beta. Capsids are imported in intact form
CC       through the nuclear pore into the nuclear basket, where it probably
CC       binds NUP153. Only capsids that contain the mature viral genome can
CC       release the viral DNA and capsid protein into the nucleoplasm. Immature
CC       capsids get stucked in the basket. Capsids encapsulate the pre-genomic
CC       RNA and the P protein. Pre-genomic RNA is reverse transcribed into DNA
CC       while the capsid is still in the cytoplasm. The capsid can then either
CC       be directed to the nucleus, providing more genome for transcription, or
CC       bud through the endoplasmic reticulum to provide new virions (By
CC       similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Homodimerizes, then multimerizes. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Capsid protein]: Virion
CC       {ECO:0000250|UniProtKB:P03148}. Host cytoplasm
CC       {ECO:0000250|UniProtKB:P03148}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative initiation; Named isoforms=2;
CC       Name=Capsid protein;
CC         IsoId=P0C6K1-1; Sequence=Displayed;
CC       Name=External core antigen;
CC         IsoId=P30027-1; Sequence=External;
CC   -!- SIMILARITY: Belongs to the avihepadnavirus core antigen family.
CC       {ECO:0000305}.
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DR   EMBL; M21953; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   SMR; P0C6K1; -.
DR   Proteomes; UP000008119; Genome.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0039619; C:T=4 icosahedral viral capsid; IEA:UniProtKB-KW.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
DR   GO; GO:0075521; P:microtubule-dependent intracellular transport of viral material towards nucleus; IEA:UniProtKB-KW.
DR   GO; GO:0046718; P:viral entry into host cell; IEA:UniProtKB-KW.
DR   GO; GO:0075732; P:viral penetration into host nucleus; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.4090.10; -; 2.
DR   InterPro; IPR002006; Hepatitis_core.
DR   InterPro; IPR036459; Viral_capsid_core_dom_sf_HBV.
DR   Pfam; PF00906; Hepatitis_core; 1.
DR   SUPFAM; SSF47852; SSF47852; 1.
PE   3: Inferred from homology;
KW   Alternative initiation; Capsid protein;
KW   Cytoplasmic inwards viral transport; DNA-binding; Host cytoplasm;
KW   Host-virus interaction; Microtubular inwards viral transport;
KW   Phosphoprotein; RNA-binding; T=4 icosahedral capsid protein;
KW   Viral penetration into host nucleus; Virion; Virus entry into host cell.
FT   CHAIN           1..262
FT                   /note="Capsid protein"
FT                   /id="PRO_0000324347"
FT   REGION          183..262
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          254..260
FT                   /note="RNA binding"
FT                   /evidence="ECO:0000250"
FT   MOTIF           215..233
FT                   /note="Bipartite nuclear localization signal"
FT                   /evidence="ECO:0000255"
FT   COMPBIAS        206..220
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        221..235
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOD_RES         232
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         239
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         245
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   262 AA;  30202 MW;  9B5B29C5DEF692E7 CRC64;
     MDINASRALA NVYDLPDDFF PKIDDLVRDA KDALEPYWKS DSIKKHVLIA THFVDLIEDF
     WQTTQGMHEI AESLRAVIPP TTAPVPTGYL IQHEEAEEIP LGDLFKHQEE RIVSFQPDYP
     ITARIHAHLK AYAKINEESL DRARRLLWWH YNCLLWGEAN VTNYISRLRT WLSTPEKYRG
     RDAPTIEAIT RPIQVAQGGR KTSSGTRKPR GLEPRRRKVK TTVVYGRRRS KSRERRAPSP
     QRAGSPLPRS SSSHHRSPSP RK