ID   HBEAG_DHBV1             Reviewed;         305 AA.
AC   P03154;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   03-AUG-2022, entry version 63.
DE   RecName: Full=External core antigen;
DE   AltName: Full=HBeAg;
DE   AltName: Full=Precore protein;
DE   Flags: Precursor;
GN   Name=C;
OS   Duck hepatitis B virus (strain United States/DHBV-16) (DHBV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Blubervirales; Hepadnaviridae; Avihepadnavirus.
OX   NCBI_TaxID=489543;
OH   NCBI_TaxID=8835; Anas (ducks).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=6699938; DOI=10.1128/jvi.49.3.782-792.1984;
RA   Mandart E., Kay A., Galibert F.;
RT   "Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison
RT   with woodchuck and human hepatitis B virus sequences.";
RL   J. Virol. 49:782-792(1984).
CC   -!- FUNCTION: May regulate immune response to the intracellular capsid in
CC       acting as a T-cell tolerogen, by having an immunoregulatory effect
CC       which prevents destruction of infected cells by cytotoxic T-cells.
CC       {ECO:0000250}.
CC   -!- SUBUNIT: Homodimerizes. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative initiation; Named isoforms=2;
CC       Name=External core antigen;
CC         IsoId=P03154-1; Sequence=Displayed;
CC       Name=Capsid protein;
CC         IsoId=P0C6J7-1; Sequence=External;
CC   -!- SIMILARITY: Belongs to the avihepadnavirus precore antigen family.
CC       {ECO:0000305}.
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DR   EMBL; K01834; AAA45741.1; -; Genomic_DNA.
DR   PIR; A03716; NKVLD.
DR   SMR; P03154; -.
DR   Proteomes; UP000180685; Genome.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
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; Host-virus interaction; Secreted; Signal;
KW   Viral immunoevasion.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000255"
FT   CHAIN           20..272
FT                   /note="External core antigen"
FT                   /id="PRO_0000222302"
FT   PROPEP          273..305
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000324680"
FT   REGION          226..305
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        249..263
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        264..278
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            272..273
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   305 AA;  34981 MW;  A3038255BBDD34AC CRC64;
     MWNLRITPLS FGAACQGIFT STLLLSCVTV PLVCTIVYDS CLYMDINASR ALANVYDLPD
     DFFPKIDDLV RDAKDALEPY WKSDSIKKHV LIATHFVDLI EDFWQTTQGM HEIAESLRAV
     IPPTTTPVPP GYLIQHEEAE EIPLGDLFKH QEERIVSFQP DYPITARIHA HLKAYAKINE
     ESLDRARRLL WWHYNCLLWG EAQVTNYISR LRTWLSTPEK YRGRDAPTIE AITRPIQVAQ
     GGRKTTTGTR KPRGLEPRRR KVKTTVVYGR RRSKSRERRA PTPQRAGSPL PRSSSSHHRS
     PSPRK