ID   TOP1_SYNE7              Reviewed;         883 AA.
AC   P34185; Q31NC3;
DT   01-FEB-1994, integrated into UniProtKB/Swiss-Prot.
DT   18-APR-2006, sequence version 2.
DT   27-MAR-2024, entry version 151.
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=Synpcc7942_1416;
OS   Synechococcus elongatus (strain ATCC 33912 / PCC 7942 / FACHB-805)
OS   (Anacystis nidulans R2).
OC   Bacteria; Cyanobacteriota; Cyanophyceae; Synechococcales; Synechococcaceae;
OC   Synechococcus.
OX   NCBI_TaxID=1140;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=7659748; DOI=10.1104/pp.108.4.1461;
RA   Ronen-Tarazi M., Lieman-Hurwitz J., Gabay C., Orus M.I., Kaplan A.;
RT   "The genomic region of rbcLS in Synechococcus sp. PCC 7942 contains genes
RT   involved in the ability to grow under low CO2 concentration and in
RT   chlorophyll biosynthesis.";
RL   Plant Physiol. 108:1461-1469(1995).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA   Kyrpides N., Lykidis A., Golden S., Richardson P.;
RT   "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL   Submitted (AUG-2005) 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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=CAA51086.1; Type=Frameshift; Evidence={ECO:0000305};
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DR   EMBL; X72391; CAA51086.1; ALT_FRAME; Genomic_DNA.
DR   EMBL; CP000100; ABB57446.1; -; Genomic_DNA.
DR   PIR; S32158; S32158.
DR   RefSeq; WP_011242453.1; NZ_JACJTX010000004.1.
DR   AlphaFoldDB; P34185; -.
DR   SMR; P34185; -.
DR   STRING; 1140.Synpcc7942_1416; -.
DR   PaxDb; 1140-Synpcc7942_1416; -.
DR   GeneID; 76400157; -.
DR   KEGG; syf:Synpcc7942_1416; -.
DR   eggNOG; COG0550; Bacteria.
DR   HOGENOM; CLU_002929_2_0_3; -.
DR   OrthoDB; 9804262at2; -.
DR   BioCyc; SYNEL:SYNPCC7942_1416-MONOMER; -.
DR   Proteomes; UP000889800; 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..883
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000145167"
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          271..294
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          842..883
FT                   /note="Disordered"
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"
FT   CONFLICT        101..102
FT                   /note="ES -> KV (in Ref. 1; CAA51086)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        392
FT                   /note="L -> V (in Ref. 1; CAA51086)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   883 AA;  98296 MW;  C90DAC6EE1202B9A CRC64;
     MPKLVIVESP TKARTIRNYL PKDYRVEASM GHVRDLPQSA SDIPTELKGE KWSNLGVDVE
     NNFAPLYIVP KDKKKIVKTL KDALKDADEL ILATDEDREG ESISWHLLQL LQPRVPTKRM
     VFHEITQEAI QAALKNCRDV DQRLVHAQET RRILDRLVGY TLSPLLWKKI AWGLSAGRVQ
     SVAVRLLVQR ERARRAFRQG SYWDLKAQLT VEAGQFEAKL WTLAGQRLAT GNDFDESTGQ
     IIAGRQVCLL DQQEAEALRD RLQTQPWQVK SLEEKPTTRK PAPPFTTSTL QQESNRKLRL
     SARETMRVAQ SLYERGFITY MRTDSVHLSQ QAIEAARSCV EQMYGKNYLS PQPRQFTTKS
     KNAQEAHEAI RPAGNTFRLP QETGLSGAEF ALYDLIWKRT IASQMAEARQ TMLSVLLEVD
     NAEFRASGKR IDFPGFFRAY VEGSDDPDAA LEDREILLPA LKVGDRPTCQ ELAAIGHETQ
     PPARYTEASL VKMLENEGIG RPSTYASIIG TIVDRGYAQL VSNTLTPTFT AFAVTALLEQ
     HFPDLVDTSF SARMEQSLDD ISNGEVDWLP YLSQFYRGDR GLEEQVKLRE SEIDPAAART
     VALEGLPAKV RIGRFGAYLE AEADGEPIKA NLPKELTPAD LDVQRVETLL RQKTEGPDQL
     GTHPETDEPI YLLTGAYGPY VQLGAATEEK PKPKRASLPK GMSLETISLE QAVGLLSLPR
     TLGEHPETGR RIQAGLGRFG PYVVCDLGGG EKDYRSLKAD DDVLTIDLDR ALELLAQPKK
     SRGRGKEPIR EVGLHPDDQA PIQIFEGPYG LYLKHGKVNA SLPEDEKPET ISLETAVAAL
     AAKAGQAKAK GGRRSTGTPK SGETKARTTK TTKKTTTRRT TSR
//