ID   TOP1_SYNY3              Reviewed;         898 AA.
AC   P73810;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1997, sequence version 1.
DT   27-MAR-2024, entry version 149.
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=slr2058;
OS   Synechocystis sp. (strain PCC 6803 / Kazusa).
OC   Bacteria; Cyanobacteriota; Cyanophyceae; Synechococcales; Merismopediaceae;
OC   Synechocystis.
OX   NCBI_TaxID=1111708;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 6803 / Kazusa;
RX   PubMed=8905231; DOI=10.1093/dnares/3.3.109;
RA   Kaneko T., Sato S., Kotani H., Tanaka A., Asamizu E., Nakamura Y.,
RA   Miyajima N., Hirosawa M., Sugiura M., Sasamoto S., Kimura T., Hosouchi T.,
RA   Matsuno A., Muraki A., Nakazaki N., Naruo K., Okumura S., Shimpo S.,
RA   Takeuchi C., Wada T., Watanabe A., Yamada M., Yasuda M., Tabata S.;
RT   "Sequence analysis of the genome of the unicellular cyanobacterium
RT   Synechocystis sp. strain PCC6803. II. Sequence determination of the entire
RT   genome and assignment of potential protein-coding regions.";
RL   DNA Res. 3:109-136(1996).
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; BA000022; BAA17864.1; -; Genomic_DNA.
DR   PIR; S74903; S74903.
DR   AlphaFoldDB; P73810; -.
DR   SMR; P73810; -.
DR   STRING; 1148.gene:10498733; -.
DR   PaxDb; 1148-1652946; -.
DR   EnsemblBacteria; BAA17864; BAA17864; BAA17864.
DR   KEGG; syn:slr2058; -.
DR   eggNOG; COG0550; Bacteria.
DR   eggNOG; COG1754; Bacteria.
DR   InParanoid; P73810; -.
DR   PhylomeDB; P73810; -.
DR   Proteomes; UP000001425; Chromosome.
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   CDD; cd03363; TOPRIM_TopoIA_TopoI; 1.
DR   Gene3D; 3.40.50.140; -; 1.
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; 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; IPR005733; TopoI_bac-type.
DR   InterPro; IPR028612; Topoisom_1_IA.
DR   InterPro; IPR025589; Toprim_C_rpt.
DR   InterPro; IPR006171; TOPRIM_domain.
DR   InterPro; IPR034149; TOPRIM_TopoI.
DR   NCBIfam; TIGR01051; topA_bact; 1.
DR   PANTHER; PTHR42785:SF1; DNA TOPOISOMERASE; 1.
DR   PANTHER; PTHR42785; DNA TOPOISOMERASE, TYPE IA, CORE; 1.
DR   Pfam; PF01131; Topoisom_bac; 1.
DR   Pfam; PF01751; Toprim; 1.
DR   Pfam; PF13368; Toprim_C_rpt; 4.
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   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; Reference proteome;
KW   Topoisomerase.
FT   CHAIN           1..898
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000145168"
FT   DOMAIN          2..126
FT                   /note="Toprim"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   DOMAIN          141..583
FT                   /note="Topo IA-type catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   REGION          175..180
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   REGION          840..898
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        859..878
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        320
FT                   /note="O-(5'-phospho-DNA)-tyrosine intermediate"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   BINDING         8
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   BINDING         95
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            32
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            151
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            152
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            155
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            160
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            167
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            322
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            515
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
SQ   SEQUENCE   898 AA;  99340 MW;  9416665977398EB3 CRC64;
     MSKLVIVESP TKARTIRNYL PQDYRVEASM GHVRDLPASA EEVPAAYKDK SWANLGVNVE
     DHFSPLYVIP KSKKKVVKEL QTALKNADEV ILATDEDREG ESISWHLLQL LQPKVPIKRM
     VFHEITQEAI RSALENCRDI DENLVHAQET RRILDRLVGY TLSPLLWKKI AWGLSAGRVQ
     SVAVRLIVQR ERARRAFKTA GYWDLKAELE QNKNPFQAKL MTLGGTKLAN GSDFDPNTGA
     LLPDKQVVVL DEAQAIALKE RLTGKPWAVV NTEEKPGVRK PSPPFTTSTL QQEANRKLGI
     SARDTMRVAQ KLYEEGYITY MRTDSVHLSD QAVTAARNCV QQMYGKEYLS PQPKQYTTKS
     KGAQEAHEAI RPAGTEFRIP NQTGLKDREL ALYELIWKRT VACQMADARI TQLSVLLKVE
     DAEFRAAGKR IDFPGYFRAY VEGSDDPDAA LENQEVILPP LKVGDRPNCR EIDTVGHETQ
     PPARYTEASL VKTLESEGVG RPSTYASIIG TIIDRGYVQM RSKALTPTFT AFAVVSLLES
     HFPDLVDTGF TSRMEQKLDE IAIGKTQWLP YLQGFFLGES GLENQVKVRQ DQIDPAIAKA
     IELENLAAKV KIGKFGPYIE IPQGEEIITA SIPQDLTPAD LNPEQVAVLL KQKTEGPDKV
     GIHPETGEPI FILIGAYGPY VQLGEATEEN KKPKRTSLPK GVKPEDVTLE MAVGLLALPR
     NLGEHPESGK NIKASLGRFG PYVVHDQGKD GKDYRSLKGD DDVLTITLER ALELLAEPKR
     GRGSRTPLKQ LGLHPEDQEP VNLFKGPYGV YIKHGKVNAS LPEGETEETI TLEKALPLLA
     EKAGSGKKTS RKKATTTAKG TKKTTSKKAS ATGTAKKTTT KRTTRKKAAS PDQSSEAG
//