ID   TOP1_FERIS              Reviewed;         699 AA.
AC   O34204;
DT   30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1998, sequence version 1.
DT   27-MAR-2024, entry version 116.
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};
OS   Fervidobacterium islandicum.
OC   Bacteria; Thermotogota; Thermotogae; Thermotogales; Fervidobacteriaceae;
OC   Fervidobacterium.
OX   NCBI_TaxID=2423;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Kaltoum H., Portemer C., Confalonieri F., Duguet M.,
RA   Bouthier de La Tour C.;
RT   "DNA topoisomerases I from thermophilic eubacteria: cloning and sequencing
RT   of the DNA topoisomerase I from Fervidobacterium islandicum.";
RL   Submitted (APR-1997) to the EMBL/GenBank/DDBJ databases.
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; U97022; AAB68788.1; -; Genomic_DNA.
DR   AlphaFoldDB; O34204; -.
DR   SMR; O34204; -.
DR   STRING; 2423.NA23_06330; -.
DR   eggNOG; COG0550; Bacteria.
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; 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   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; Topoisomerase; Zinc;
KW   Zinc-finger.
FT   CHAIN           1..699
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000145148"
FT   DOMAIN          38..146
FT                   /note="Toprim"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   DOMAIN          160..583
FT                   /note="Topo IA-type catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   ZN_FING         601..624
FT                   /note="C4-type"
FT   REGION          1..37
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          194..199
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   REGION          649..699
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        673..699
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        324
FT                   /note="O-(5'-phospho-DNA)-tyrosine intermediate"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01383"
FT   BINDING         44
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   BINDING         115
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            68
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            170
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            174
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            179
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            186
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00952"
FT   SITE            326
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   699 AA;  79612 MW;  9137E85A8A01FD2C CRC64;
     MAKSKVVEKD KKNELDNQSA DIELKGQSKN EESKGGKKKV IIVESPAKAK TIERILGNDY
     QVISSKGHIR DLPQKQFGVD LNSLKLDFEI IPGKESVVEQ IKKMTSGKEV LLPSDQDREG
     EAIAWHLSTI LGVKGKNIIT FTEITERAIK EAVKNPREID MNKVNAQLAR RVLDRIVGYM
     ISPLLWRIIK DARSAGRVQS AALKIICERE RERYRFVPQK YFKVWIDIAG LKAYLTKVDG
     KKIKPTDITE EISKDVLQKV KSVRLVDIDV KEVRKNPPAP FITSTLQQDA ASKLGFPVSK
     TMKIAQELYE GVDTKEGHTA FITYMRTDST RVSDVAKEAA EKFILKNFGR EYLNESSEVA
     SKKGSKTKGK VQDAHECIRP VDVNITPEKA KELLDKDHHK LYELIWKRFI ASQMSSAIYK
     QYSYDFESGK YVFEASIRER IFDGFEKVYT IDNEPSEKHK ELKVDQEYLV EPKSAEAQTT
     PPDRYTEASL VKTLEMEGIG RPSTYATIIQ TLLDRGYVVK KRKTLIPTIL GFVVNHYLEQ
     RFPDIVDKGF TAEMEKELDE VENGKKDWKE VVKSFLKEFN KDLERAKNEF FAIDFDTDIT
     CEDCSGNYKL KVGKYGLYLH CPNCKTNKAL KSDVFGVIDG NKLYVLEEQE SQEENGEKNS
     VQSEESSANS GNRKFYRKRR TSGSKKSSTK SASSKAKKK
//