ID   TOP1_BUCAP              Reviewed;         853 AA.
AC   Q8K9P7;
DT   08-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   27-MAR-2024, entry version 135.
DE   RecName: Full=DNA topoisomerase 1 {ECO:0000255|HAMAP-Rule:MF_00952};
DE            EC=5.6.2.1 {ECO:0000255|HAMAP-Rule:MF_00952};
DE   AltName: Full=DNA topoisomerase I {ECO:0000255|HAMAP-Rule:MF_00952};
DE   AltName: Full=Omega-protein;
DE   AltName: Full=Relaxing enzyme;
DE   AltName: Full=Swivelase;
DE   AltName: Full=Untwisting enzyme;
GN   Name=topA {ECO:0000255|HAMAP-Rule:MF_00952};
GN   OrderedLocusNames=BUsg_273;
OS   Buchnera aphidicola subsp. Schizaphis graminum (strain Sg).
OC   Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=198804;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Sg;
RX   PubMed=12089438; DOI=10.1126/science.1071278;
RA   Tamas I., Klasson L., Canbaeck B., Naeslund A.K., Eriksson A.-S.,
RA   Wernegreen J.J., Sandstroem J.P., Moran N.A., Andersson S.G.E.;
RT   "50 million years of genomic stasis in endosymbiotic bacteria.";
RL   Science 296:2376-2379(2002).
CC   -!- FUNCTION: Releases the supercoiling and torsional tension of DNA, which
CC       is introduced during the DNA replication and transcription, by
CC       transiently cleaving and rejoining one strand of the DNA duplex.
CC       Introduces a single-strand break via transesterification at a target
CC       site in duplex DNA. The scissile phosphodiester is attacked by the
CC       catalytic tyrosine of the enzyme, resulting in the formation of a DNA-
CC       (5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH
CC       DNA strand. The free DNA strand then undergoes passage around the
CC       unbroken strand, thus removing DNA supercoils. Finally, in the
CC       religation step, the DNA 3'-OH attacks the covalent intermediate to
CC       expel the active-site tyrosine and restore the DNA phosphodiester
CC       backbone. {ECO:0000255|HAMAP-Rule:MF_00952}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP-independent breakage of single-stranded DNA, followed by
CC         passage and rejoining.; EC=5.6.2.1; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00952};
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00952};
CC   -!- SUBUNIT: Monomer. {ECO:0000255|HAMAP-Rule:MF_00952}.
CC   -!- SIMILARITY: Belongs to the type IA topoisomerase family.
CC       {ECO:0000255|HAMAP-Rule:MF_00952}.
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DR   EMBL; AE013218; AAM67831.1; -; Genomic_DNA.
DR   RefSeq; WP_011053798.1; NC_004061.1.
DR   AlphaFoldDB; Q8K9P7; -.
DR   SMR; Q8K9P7; -.
DR   STRING; 198804.BUsg_273; -.
DR   GeneID; 75258848; -.
DR   KEGG; bas:BUsg_273; -.
DR   eggNOG; COG0550; Bacteria.
DR   HOGENOM; CLU_002929_4_3_6; -.
DR   Proteomes; UP000000416; Chromosome.
DR   GO; GO:0005694; C:chromosome; IEA:InterPro.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003917; F:DNA topoisomerase type I (single strand cut, ATP-independent) activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0006265; P:DNA topological change; IEA:UniProtKB-UniRule.
DR   CDD; cd00186; TOP1Ac; 1.
DR   Gene3D; 2.20.25.10; -; 1.
DR   Gene3D; 3.40.50.140; -; 1.
DR   Gene3D; 3.30.65.10; Bacterial Topoisomerase I, domain 1; 3.
DR   Gene3D; 1.10.460.10; Topoisomerase I, domain 2; 1.
DR   Gene3D; 2.70.20.10; Topoisomerase I, domain 3; 1.
DR   Gene3D; 1.10.290.10; Topoisomerase I, domain 4; 1.
DR   HAMAP; MF_00952; Topoisom_1_prok; 1.
DR   InterPro; IPR049330; TOP1_Znf.
DR   InterPro; IPR000380; Topo_IA.
DR   InterPro; IPR003601; Topo_IA_2.
DR   InterPro; IPR023406; Topo_IA_AS.
DR   InterPro; IPR013497; Topo_IA_cen.
DR   InterPro; IPR013824; Topo_IA_cen_sub1.
DR   InterPro; IPR013825; Topo_IA_cen_sub2.
DR   InterPro; IPR013826; Topo_IA_cen_sub3.
DR   InterPro; IPR023405; Topo_IA_core_domain.
DR   InterPro; IPR003602; Topo_IA_DNA-bd_dom.
DR   InterPro; IPR013498; Topo_IA_Znf.
DR   InterPro; IPR005733; TopoI_bac-type.
DR   InterPro; IPR013263; TopoI_Znr_bac.
DR   InterPro; IPR028612; Topoisom_1_IA.
DR   InterPro; IPR006171; TOPRIM_domain.
DR   NCBIfam; TIGR01051; topA_bact; 1.
DR   PANTHER; PTHR42785:SF1; DNA TOPOISOMERASE; 1.
DR   PANTHER; PTHR42785; DNA TOPOISOMERASE, TYPE IA, CORE; 1.
DR   Pfam; PF21372; TOP1_ZnF; 1.
DR   Pfam; PF08272; Topo_Zn_Ribbon; 2.
DR   Pfam; PF01131; Topoisom_bac; 1.
DR   Pfam; PF01751; Toprim; 1.
DR   Pfam; PF01396; zf-C4_Topoisom; 2.
DR   PRINTS; PR00417; PRTPISMRASEI.
DR   SMART; SM00437; TOP1Ac; 1.
DR   SMART; SM00436; TOP1Bc; 1.
DR   SMART; SM00493; TOPRIM; 1.
DR   SUPFAM; SSF56712; Prokaryotic type I DNA topoisomerase; 1.
DR   SUPFAM; SSF57783; Zinc beta-ribbon; 2.
DR   PROSITE; PS00396; TOPO_IA_1; 1.
DR   PROSITE; PS52039; TOPO_IA_2; 1.
DR   PROSITE; PS50880; TOPRIM; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Isomerase; Magnesium; Metal-binding; Repeat; Topoisomerase;
KW   Zinc; Zinc-finger.
FT   CHAIN           1..853
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000145145"
FT   DOMAIN          3..136
FT                   /note="Toprim"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   DOMAIN          152..565
FT                   /note="Topo IA-type catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   ZN_FING         589..621
FT                   /note="C4-type 1"
FT   ZN_FING         649..676
FT                   /note="C4-type 2"
FT   ZN_FING         699..724
FT                   /note="C4-type 3"
FT   REGION          186..191
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   ACT_SITE        313
FT                   /note="O-(5'-phospho-DNA)-tyrosine intermediate"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   BINDING         9
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   BINDING         105
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            33
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            162
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            163
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            166
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            171
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            178
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            315
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
SQ   SEQUENCE   853 AA;  98816 MW;  99B454AB78AC6D1B CRC64;
     MCKSLVIVES PVKAKTISKY LGKQYIVKSS VGHVRDLINN KSKNKKNIKK SNIKHNEKTA
     LIQQMGINPY KNWKAEYHIL PGKEKIISEL KNIANKVHYI YLATDLDREG EAIAWHLKEV
     IGGNSLKFRR VVFNEITKKS IEKAFQNIGK INMNRVYSQQ ARRFMDRIVG YMISPLLWKK
     ISRGLSAGRV QSAAVRLITD REYEIKNFIE REHWKISLSL LSKENKKVTM DITHYRNKTF
     LLNNKKEVNS TIEKIKNLSF IITDRKDKIF KKKPPAPLIT STLQQASNID LGFSVKKTMF
     LAQKLYEQGY ITYIRTDSYF LSNYAIEKVR SYIENFYGSD FLPKKSNIYS NQKYSQEAHE
     AIRPSDVQVV NIDNCDPDAK KLYKLIWNYF IASQMKSERY KSIKTTVMAD VFKLQSNTKI
     VLFSGWTKIL KKSNNVNFKF PVLDIGTTLI LDKILPHQIF TKPPPRFSES SLVRELEKKG
     IGRPSTYATI ITKIKEKGYL KIKKNKFYAA KIGEILITRL KKNFSDLVDY DFTARMEKNL
     DQVSDKLINW KHLLNSFFDN FSQQLEQAKK PPEEGGMELN TTVPTEIDCS LCNKKMGIKT
     AVTGVFLSCL GYNSEPNEKR CKNTINLISL NDLSTTKKEE KNFHLKNRCK KCNLVMDVYL
     INENLKIFIC INNPSCNGYN LKKGIFKKSL NCSLKKIKCE KCKNDMLFKT GRFGNFFMCI
     NDTCKNTRKI LPNGEISEPK FEPIPFPDIL CEKSNTWFVL REGISGIFFA ANTFPKSRET
     RSPFVEELAR FEYLLPKKLH YLASAPQRDN KGNKTIVCFN KLNKQQYIAS KKEGKFTGWA
     AFFIDRKWCI VNK
//