ID   KITH_STRGC              Reviewed;         191 AA.
AC   P47848; A8AXD2;
DT   01-FEB-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 1.
DT   04-NOV-2026, entry version 132.
DE   RecName: Full=Thymidine kinase {ECO:0000255|HAMAP-Rule:MF_00124};
DE            EC=2.7.1.21 {ECO:0000255|HAMAP-Rule:MF_00124};
GN   Name=tdk {ECO:0000255|HAMAP-Rule:MF_00124};
GN   OrderedLocusNames=SGO_1155;
OS   Streptococcus gordonii (strain Challis / ATCC 35105 / BCRC 15272 / CH1 /
OS   DL1 / V288).
OC   Bacteria; Bacillati; Bacillota; Bacilli; Lactobacillales; Streptococcaceae;
OC   Streptococcus.
OX   NCBI_TaxID=467705;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8598265; DOI=10.1111/j.1574-6968.1996.tb07973.x;
RA   McNab R.;
RT   "Cloning and sequence analysis of thymidine kinase from the oral bacterium
RT   Streptococcus gordonii.";
RL   FEMS Microbiol. Lett. 135:103-110(1996).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Challis / ATCC 35105 / BCRC 15272 / CH1 / DL1 / V288;
RX   PubMed=17720781; DOI=10.1128/jb.01023-07;
RA   Vickerman M.M., Iobst S., Jesionowski A.M., Gill S.R.;
RT   "Genome-wide transcriptional changes in Streptococcus gordonii in response
RT   to competence signaling peptide.";
RL   J. Bacteriol. 189:7799-7807(2007).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=thymidine + ATP = dTMP + ADP + H(+); Xref=Rhea:RHEA:19129,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:17748, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:63528, ChEBI:CHEBI:456216; EC=2.7.1.21;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00124};
CC   -!- SUBUNIT: Homotetramer. {ECO:0000255|HAMAP-Rule:MF_00124}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_00124}.
CC   -!- SIMILARITY: Belongs to the thymidine kinase family. {ECO:0000255|HAMAP-
CC       Rule:MF_00124}.
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DR   EMBL; L40415; AAB02289.1; -; Genomic_DNA.
DR   EMBL; CP000725; ABV10749.1; -; Genomic_DNA.
DR   RefSeq; WP_008808654.1; NC_009785.1.
DR   AlphaFoldDB; P47848; -.
DR   SMR; P47848; -.
DR   STRING; 467705.SGO_1155; -.
DR   KEGG; sgo:SGO_1155; -.
DR   eggNOG; COG1435; Bacteria.
DR   HOGENOM; CLU_064400_2_2_9; -.
DR   OMA; AACIFVD; -.
DR   Proteomes; UP000001131; Chromosome.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0004797; F:thymidine kinase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0008270; F:zinc ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0006259; P:DNA metabolic process; IEA:UniProtKB-UniRule.
DR   GO; GO:0046104; P:thymidine metabolic process; IEA:TreeGrafter.
DR   Gene3D; 3.30.60.20; -; 1.
DR   Gene3D; 3.40.50.300; P-loop containing nucleotide triphosphate hydrolases; 1.
DR   HAMAP; MF_00124; Thymidine_kinase; 1.
DR   InterPro; IPR027417; P-loop_NTPase.
DR   InterPro; IPR001267; Thymidine_kinase.
DR   InterPro; IPR020633; Thymidine_kinase_CS.
DR   NCBIfam; NF003299; PRK04296.1-4; 1.
DR   NCBIfam; NF003300; PRK04296.1-5; 1.
DR   PANTHER; PTHR11441; THYMIDINE KINASE; 1.
DR   PANTHER; PTHR11441:SF0; THYMIDINE KINASE, CYTOSOLIC; 1.
DR   Pfam; PF00265; TK; 1.
DR   PIRSF; PIRSF035805; TK_cell; 1.
DR   SUPFAM; SSF57716; Glucocorticoid receptor-like (DNA-binding domain); 1.
DR   SUPFAM; SSF52540; P-loop containing nucleoside triphosphate hydrolases; 1.
DR   PROSITE; PS00603; TK_CELLULAR_TYPE; 1.
PE   3: Inferred from homology;
KW   ATP-binding; Cytoplasm; DNA synthesis; Kinase; Metal-binding;
KW   Nucleotide-binding; Reference proteome; Transferase; Zinc.
FT   CHAIN           1..191
FT                   /note="Thymidine kinase"
FT                   /id="PRO_0000175030"
FT   ACT_SITE        86
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         9..16
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         85..88
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         143
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         146
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         180
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
FT   BINDING         183
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00124"
SQ   SEQUENCE   191 AA;  21842 MW;  3F3EB8E3C5035283 CRC64;
     MAQLYYKYGT MNSGKTIEIL KVAHNYEEQG KGVVIMTSAV DTRDGVGYVS SRIGMKRQAM
     AIEDDTDILG YIKNLPEKPY CILIDEAQFL KRHHVYDLAR VVDELDVPVM AFGLKNDFRN
     ELFEGSKHLL LLADKIEEIK TICQYCSRKA TMVLRTDHGK PVYDGEQIQI GGNETYIPVC
     RKHYFKPDIN N
//