ID   CAPSD_HHBV              Reviewed;         262 AA.
AC   P0C6K0;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   18-MAR-2008, sequence version 1.
DT   03-AUG-2022, entry version 62.
DE   RecName: Full=Capsid protein;
DE   AltName: Full=Core antigen;
DE   AltName: Full=Core protein;
DE   AltName: Full=HBcAg;
GN   Name=C;
OS   Heron hepatitis B virus (HHBV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Blubervirales; Hepadnaviridae; Avihepadnavirus.
OX   NCBI_TaxID=28300;
OH   NCBI_TaxID=8899; Ardeidae (herons).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3418788; DOI=10.1128/jvi.62.10.3832-3839.1988;
RA   Sprengel R., Kaleta E.F., Will H.;
RT   "Isolation and characterization of a hepatitis B virus endemic in herons.";
RL   J. Virol. 62:3832-3839(1988).
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=P0C6K0-1; Sequence=Displayed;
CC       Name=External core antigen;
CC         IsoId=P13845-1; Sequence=External;
CC   -!- SIMILARITY: Belongs to the avihepadnavirus core antigen family.
CC       {ECO:0000305}.
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DR   EMBL; M22056; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   SMR; P0C6K0; -.
DR   Proteomes; UP000008679; 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; -; 1.
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_0000324349"
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        210..236
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        237..262
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOD_RES         232
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;  30191 MW;  E9E1EFF7D88C9D1A CRC64;
     MDVNASRALA NVYDLPDDFF PQIDDLVRDA KDALEPYWKA ETIKKHVLIA THFVDLIEDF
     WQTTQGMSQI ADALRAVIPP TTVPVPEGFL ITHSEAEEIP LNDLFSNQEE RIVNFQPDYP
     ITARIHTHLR VYTKLNEQAL DKARRLLWWH YNCLLWGEAT VTNYISRLRT WLSTPEKYRG
     KDAPTIEAIT RPIQVAQGGR NQTKGTRKPR GLEPRRRKVK TTVVYGRRRS KSRGRRSSPS
     QRAGSPLPRN RGNQTRSPSP RE