ID   I3_VACCP                Reviewed;          28 AA.
AC   Q00334;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1993, sequence version 1.
DT   12-AUG-2020, entry version 43.
DE   RecName: Full=Protein I3;
DE   Flags: Fragment;
GN   ORFNames=I3L;
OS   Vaccinia virus (strain L-IVP) (VACV).
OC   Viruses; Varidnaviria; Bamfordvirae; Nucleocytoviricota; Pokkesviricetes;
OC   Chitovirales; Poxviridae; Chordopoxvirinae; Orthopoxvirus; Vaccinia virus.
OX   NCBI_TaxID=31531;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2250685;
RA   Riazankina O.I., Shchelkunov S.N., Muravlev A.I., Netesova N.A.,
RA   Mikriukov N.N., Gutorov V.V., Nikulin A.E., Kulichkov V.A., Malygin E.G.;
RT   "Molecular-biological study of vaccinia virus genome. II. Localization and
RT   nucleotide sequence of vaccinia virus genes coding for proteins 36K and
RT   12K.";
RL   Mol. Biol. (Mosk.) 24:968-976(1990).
CC   -!- FUNCTION: Single-stranded DNA (ssDNA)-binding phosphoprotein which
CC       stimulates the enzymatic activity of vaccinia ribonucleotide reductase.
CC       In the absence of magnesium and at low I3 concentration, I3 forms
CC       beaded nucleosome-like structures on ssDNA. In the presence of
CC       magnesium and at high I3 concentration, I3 and DNA aggregate into large
CC       branched filamentous structures. Might be essential for viral parental
CC       DNA replication.
CC   -!- SUBUNIT: Homooctamer (Potential). Homoomultimer (Potential). Interacts
CC       with the small subunit of ribonucleotide reductase; this interaction
CC       stimulates ribonucleotide reductase activity. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000305}. Note=Localizes in
CC       cytoplasmic virus factories, where it is associated with viral DNA.
CC       {ECO:0000305}.
CC   -!- INDUCTION: Expressed in the early phase of the viral replicative cycle.
CC   -!- MISCELLANEOUS: This protein is synthesized in the early as well as at
CC       the intermediate time of infection.
CC   -!- SIMILARITY: Belongs to the chordopoxvirinae I3 family. {ECO:0000305}.
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DR   EMBL; X61165; CAA43473.1; -; Genomic_DNA.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0030261; P:chromosome condensation; IEA:UniProtKB-KW.
PE   2: Evidence at transcript level;
KW   DNA condensation; DNA-binding; Early protein; Host cytoplasm.
FT   CHAIN           <1..28
FT                   /note="Protein I3"
FT                   /id="PRO_0000099572"
FT   NON_TER         1
SQ   SEQUENCE   28 AA;  3238 MW;  CE10813AC544F010 CRC64;
     DLARNLGLVD IDDEYDEDSD KEKPIFNV