ID   K3_VACCW                Reviewed;          88 AA.
AC   P18378; Q76ZX7;
DT   01-NOV-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1990, sequence version 1.
DT   25-MAY-2022, entry version 103.
DE   RecName: Full=Protein K3;
DE   AltName: Full=Protein K2;
GN   OrderedLocusNames=VACWR034; ORFNames=K2L, K3L;
OS   Vaccinia virus (strain Western Reserve) (VACV) (Vaccinia virus (strain
OS   WR)).
OC   Viruses; Varidnaviria; Bamfordvirae; Nucleocytoviricota; Pokkesviricetes;
OC   Chitovirales; Poxviridae; Chordopoxvirinae; Orthopoxvirus; Vaccinia virus.
OX   NCBI_TaxID=10254;
OH   NCBI_TaxID=9913; Bos taurus (Bovine).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3264331; DOI=10.1099/0022-1317-69-12-2995;
RA   Boursnell M.E.G., Foulds I.J., Campbell J.I., Binns M.M.;
RT   "Non-essential genes in the vaccinia virus HindIII K fragment: a gene
RT   related to serine protease inhibitors and a gene related to the 37K
RT   vaccinia virus major envelope antigen.";
RL   J. Gen. Virol. 69:2995-3003(1988).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RA   Esposito J.J., Frace A.M., Sammons S.A., Olsen-Rasmussen M., Osborne J.,
RA   Wohlhueter R.;
RT   "Sequencing of the coding region of Vaccinia-WR to an average 9-fold
RT   redundancy and an error rate of 0.16/10kb.";
RL   Submitted (FEB-2003) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   FUNCTION.
RC   STRAIN=Wisconsin;
RX   PubMed=8099586; DOI=10.1016/s0021-9258(18)31463-7;
RA   Carroll K., Elroy-Stein O., Moss B., Jagus R.;
RT   "Recombinant vaccinia virus K3L gene product prevents activation of double-
RT   stranded RNA-dependent, initiation factor 2 alpha-specific protein
RT   kinase.";
RL   J. Biol. Chem. 268:12837-12842(1993).
RN   [4]
RP   X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS).
RX   PubMed=12191475; DOI=10.1016/s1097-2765(02)00590-7;
RA   Dar A.C., Sicheri F.;
RT   "X-ray crystal structure and functional analysis of vaccinia virus K3L
RT   reveals molecular determinants for PKR subversion and substrate
RT   recognition.";
RL   Mol. Cell 10:295-305(2002).
CC   -!- FUNCTION: Viral mimic of eIF-2-alpha that acts as a pseudosubstrate for
CC       EIF2AK2/PKR kinase. Inhibits therefore eIF-2-alpha phosphorylation by
CC       host EIF2AK2/PKR kinase and prevents protein synthesis shutoff.
CC       {ECO:0000269|PubMed:8099586}.
CC   -!- SUBUNIT: Interacts with host PKR kinase. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the poxviridae K3 protein family. {ECO:0000305}.
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DR   EMBL; D00382; BAA00288.1; -; Genomic_DNA.
DR   EMBL; AY243312; AAO89313.1; -; Genomic_DNA.
DR   PIR; JS0212; WMVZK2.
DR   RefSeq; YP_232916.1; NC_006998.1.
DR   PDB; 1LUZ; X-ray; 1.80 A; A/B=1-88.
DR   PDBsum; 1LUZ; -.
DR   SMR; P18378; -.
DR   DNASU; 3707649; -.
DR   GeneID; 3707649; -.
DR   KEGG; vg:3707649; -.
DR   EvolutionaryTrace; P18378; -.
DR   Proteomes; UP000000344; Genome.
DR   GO; GO:0030414; F:peptidase inhibitor activity; IEA:InterPro.
DR   GO; GO:0030291; F:protein serine/threonine kinase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0039580; P:suppression by virus of host PKR signaling; IEA:UniProtKB-KW.
DR   GO; GO:0039502; P:suppression by virus of host type I interferon-mediated signaling pathway; IEA:UniProtKB-KW.
DR   Gene3D; 2.40.50.140; -; 1.
DR   InterPro; IPR012340; NA-bd_OB-fold.
DR   InterPro; IPR022967; S1_dom.
DR   InterPro; IPR003029; S1_domain.
DR   InterPro; IPR016397; Serpin_prd_poxvir.
DR   Pfam; PF00575; S1; 1.
DR   PIRSF; PIRSF003760; VAC_K3L_Serpin_prd; 1.
DR   SMART; SM00316; S1; 1.
DR   SUPFAM; SSF50249; SSF50249; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Host-virus interaction;
KW   Inhibition of host innate immune response by virus;
KW   Inhibition of host interferon signaling pathway by virus;
KW   Inhibition of host PKR by virus; Reference proteome; RNA-binding;
KW   Viral immunoevasion.
FT   CHAIN           1..88
FT                   /note="Protein K3"
FT                   /id="PRO_0000099599"
FT   DOMAIN          8..82
FT                   /note="S1 motif"
FT   STRAND          14..22
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   STRAND          25..30
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   STRAND          36..40
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   HELIX           41..43
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   HELIX           48..58
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   STRAND          62..71
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   TURN            72..75
FT                   /evidence="ECO:0007829|PDB:1LUZ"
FT   STRAND          76..84
FT                   /evidence="ECO:0007829|PDB:1LUZ"
SQ   SEQUENCE   88 AA;  10556 MW;  EC6AD69CC3FAE4EA CRC64;
     MLAFCYSLPN AGDVIKGRVY EKDYALYIYL FDYPHFEAIL AESVKMHMDR YVEYRDKLVG
     KTVKVKVIRV DYTKGYIDVN YKRMCRHQ