ID   HBEAG_ASHV              Reviewed;         217 AA.
AC   Q64896;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 79.
DE   RecName: Full=External core antigen {ECO:0000255|HAMAP-Rule:MF_04076};
DE   AltName: Full=HBeAg {ECO:0000255|HAMAP-Rule:MF_04076};
DE   AltName: Full=Precore protein {ECO:0000255|HAMAP-Rule:MF_04076};
DE   AltName: Full=p25 {ECO:0000255|HAMAP-Rule:MF_04076};
DE   Flags: Precursor;
GN   Name=C {ECO:0000255|HAMAP-Rule:MF_04076};
OS   Arctic squirrel hepatitis virus (ASHV).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Blubervirales; Hepadnaviridae; Orthohepadnavirus.
OX   NCBI_TaxID=41952;
OH   NCBI_TaxID=259022; Urocitellus parryii kennicottii.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8676441; DOI=10.1128/jvi.70.7.4210-4219.1996;
RA   Testut P., Renard C.A., Terradillos O., Vitvitski-Trepo L., Tekaia F.,
RA   Degott C., Blake J., Boyer B., Buendia M.A.;
RT   "A new hepadnavirus endemic in arctic ground squirrels in Alaska.";
RL   J. Virol. 70:4210-4219(1996).
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. This
CC       immune regulation may predispose to chronicity during perinatal
CC       infections and prevent severe liver injury during adult infections.
CC       {ECO:0000255|HAMAP-Rule:MF_04076}.
CC   -!- SUBUNIT: Homodimerizes. {ECO:0000255|HAMAP-Rule:MF_04076}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000255|HAMAP-Rule:MF_04076}. Host
CC       nucleus {ECO:0000255|HAMAP-Rule:MF_04076}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative initiation; Named isoforms=2;
CC       Name=External core antigen;
CC         IsoId=Q64896-1; Sequence=Displayed;
CC       Name=Capsid protein;
CC         IsoId=Q64897-1; Sequence=External;
CC   -!- PTM: Phosphorylated. {ECO:0000255|HAMAP-Rule:MF_04076}.
CC   -!- PTM: Cleaved by host furin. {ECO:0000255|HAMAP-Rule:MF_04076}.
CC   -!- SIMILARITY: Belongs to the orthohepadnavirus precore antigen family.
CC       {ECO:0000255|HAMAP-Rule:MF_04076}.
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DR   EMBL; U29144; AAB08030.1; -; Genomic_DNA.
DR   SMR; Q64896; -.
DR   Proteomes; UP000008172; Genome.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-UniRule.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0039619; C:T=4 icosahedral viral capsid; IEA:UniProtKB-UniRule.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0005198; F:structural molecule activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0075521; P:microtubule-dependent intracellular transport of viral material towards nucleus; IEA:UniProtKB-UniRule.
DR   GO; GO:0046718; P:viral entry into host cell; IEA:UniProtKB-UniRule.
DR   GO; GO:0075732; P:viral penetration into host nucleus; IEA:UniProtKB-UniRule.
DR   Gene3D; 1.10.4090.10; -; 1.
DR   HAMAP; MF_04076; HBV_HBEAG; 1.
DR   InterPro; IPR013195; Hepatitis_B_virus_capsid_N.
DR   InterPro; IPR002006; Hepatitis_core.
DR   InterPro; IPR036459; Viral_capsid_core_dom_sf_HBV.
DR   Pfam; PF08290; Hep_core_N; 1.
DR   Pfam; PF00906; Hepatitis_core; 2.
DR   SUPFAM; SSF47852; SSF47852; 1.
PE   3: Inferred from homology;
KW   Alternative initiation; Disulfide bond; Host nucleus;
KW   Host-virus interaction; Reference proteome; Repeat; Secreted; Signal;
KW   Viral immunoevasion.
FT   SIGNAL          1..20
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
FT   CHAIN           21..217
FT                   /note="External core antigen"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
FT                   /id="PRO_0000324687"
FT   PROPEP          190..217
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000324688"
FT   REPEAT          190..196
FT                   /note="1; half-length"
FT   REPEAT          197..204
FT                   /note="2"
FT   REPEAT          205..211
FT                   /note="3"
FT   REGION          26..28
FT                   /note="HBEAG"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
FT   REGION          181..217
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          190..211
FT                   /note="3 X 8 AA approximate repeats of S-P-R-R-R-R-[PS]-Q"
FT   COMPBIAS        183..207
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            189..190
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
FT   DISULFID        78
FT                   /note="Interchain"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
FT   DISULFID        91
FT                   /note="Interchain"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04076"
SQ   SEQUENCE   217 AA;  25097 MW;  8E24D597E7FD04D8 CRC64;
     MYLFHLCLVF ACVSCPTVQA SKLCLGWLWD MDIDPYKEFG SSYQLLNFLP LDFFPELNAL
     VDTATALYEE ELTGREHCSP HHTAIRQALV CWEELTRLIA WMSANINSEE VRRVIVAHVN
     DTWGLKVRQN LWFHLSCLTF GQHTVQEFLV SFGVRIRTPA PYRPPNAPIL STLPEHTVIR
     RRGSARVVRS PRRRTPSPRR RRSQSPRRRP QSPASNC