ID   RIR2_VARV               Reviewed;         319 AA.
AC   P0DSS8; P33799;
DT   16-OCT-2019, integrated into UniProtKB/Swiss-Prot.
DT   16-OCT-2019, sequence version 1.
DT   03-AUG-2022, entry version 12.
DE   RecName: Full=Ribonucleoside-diphosphate reductase small chain;
DE            EC=1.17.4.1;
DE   AltName: Full=Ribonucleotide reductase small subunit;
GN   ORFNames=C8L, F4L;
OS   Variola virus.
OC   Viruses; Varidnaviria; Bamfordvirae; Nucleocytoviricota; Pokkesviricetes;
OC   Chitovirales; Poxviridae; Chordopoxvirinae; Orthopoxvirus.
OX   NCBI_TaxID=10255;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=Bangladesh-1975;
RX   PubMed=8264798; DOI=10.1038/366748a0;
RA   Massung R.F., Esposito J.J., Liu L.I., Qi J., Utterback T.R., Knight J.C.,
RA   Aubin L., Yuran T.E., Parsons J.M., Loparev V.N., Selivanov N.A.,
RA   Cavallaro K.F., Kerlavage A.R., Mahy B.W.J., Venter J.C.;
RT   "Potential virulence determinants in terminal regions of variola smallpox
RT   virus genome.";
RL   Nature 366:748-751(1993).
CC   -!- FUNCTION: Ribonucleoside-diphosphate reductase holoenzyme provides the
CC       precursors necessary for viral DNA synthesis. Allows virus growth in
CC       non-dividing cells. Catalyzes the biosynthesis of deoxyribonucleotides
CC       from the corresponding ribonucleotides (By similarity). {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[thioredoxin]-disulfide + a 2'-deoxyribonucleoside 5'-
CC         diphosphate + H2O = [thioredoxin]-dithiol + a ribonucleoside 5'-
CC         diphosphate; Xref=Rhea:RHEA:23252, Rhea:RHEA-COMP:10698, Rhea:RHEA-
CC         COMP:10700, ChEBI:CHEBI:15377, ChEBI:CHEBI:29950, ChEBI:CHEBI:50058,
CC         ChEBI:CHEBI:57930, ChEBI:CHEBI:73316; EC=1.17.4.1;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU10014};
CC   -!- COFACTOR:
CC       Name=Fe cation; Xref=ChEBI:CHEBI:24875; Evidence={ECO:0000250};
CC       Note=Binds 2 iron ions per subunit. {ECO:0000250};
CC   -!- PATHWAY: Genetic information processing; DNA replication.
CC   -!- SUBUNIT: Heterotetramer composed of a homodimer of the large subunit
CC       (R1) and a homodimer of the small subunit (R2). Larger multisubunit
CC       protein complex are also active, composed of (R1)n(R2)n (By
CC       similarity). {ECO:0000250}.
CC   -!- INDUCTION: Expressed early in the viral replicative cycle.
CC   -!- SIMILARITY: Belongs to the ribonucleoside diphosphate reductase small
CC       chain family. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAA60776.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; L22579; AAA60776.1; ALT_INIT; Genomic_DNA.
DR   PIR; T28466; T28466.
DR   SMR; P0DSS8; -.
DR   UniPathway; UPA00326; -.
DR   Proteomes; UP000119805; Genome.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0004748; F:ribonucleoside-diphosphate reductase activity, thioredoxin disulfide as acceptor; IEA:UniProtKB-EC.
DR   GO; GO:0009263; P:deoxyribonucleotide biosynthetic process; IEA:InterPro.
DR   GO; GO:0006260; P:DNA replication; IEA:UniProtKB-UniPathway.
DR   CDD; cd01049; RNRR2; 1.
DR   Gene3D; 1.10.620.20; -; 1.
DR   InterPro; IPR009078; Ferritin-like_SF.
DR   InterPro; IPR012348; RNR-like.
DR   InterPro; IPR033909; RNR_small.
DR   InterPro; IPR030475; RNR_small_AS.
DR   InterPro; IPR000358; RNR_small_fam.
DR   PANTHER; PTHR23409; PTHR23409; 1.
DR   Pfam; PF00268; Ribonuc_red_sm; 1.
DR   SUPFAM; SSF47240; SSF47240; 1.
DR   PROSITE; PS00368; RIBORED_SMALL; 1.
PE   2: Evidence at transcript level;
KW   Deoxyribonucleotide synthesis; Early protein; Iron; Metal-binding;
KW   Oxidoreductase.
FT   CHAIN           1..319
FT                   /note="Ribonucleoside-diphosphate reductase small chain"
FT                   /id="PRO_0000448120"
FT   ACT_SITE        108
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10014"
FT   BINDING         70
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10014"
FT   BINDING         101
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10014"
FT   BINDING         101
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
FT   BINDING         104
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10014"
FT   BINDING         163
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
FT   BINDING         197
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
FT   BINDING         200
FT                   /ligand="Fe cation"
FT                   /ligand_id="ChEBI:CHEBI:24875"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   319 AA;  37074 MW;  8E6336ED7EBD5977 CRC64;
     MEPILAKNPN RFVIFPIQYH DIWNMYKKAE ASFWTVEEVD ISKDINDWNK LTPDEKYFIK
     HVLAFFAASD GIVNENLAER FCIEVQITEA RCFYGFQMAI ENIHSEMYSL LIDTYVKDSN
     EKNYLFNAIE TMPCVKKKAD WAQKWIHDSA SYGERLIAFA AVEGIFFSGS FASIFWLKKR
     GLMPGLTFSN ELISRDEGLH CDFACLMFKH LLYPPSEETV RSIITDAVSI EQEFLTVALP
     VKLIGMNCEM MKTYIKFVAD RLISELGFKK IYNVTNPFDF MENISLEGKT NFFEKRVGEY
     QKMGVMSQED NHFSLDVDF