ID   TOP1_DICDI              Reviewed;         893 AA.
AC   Q54RC3;
DT   29-APR-2008, integrated into UniProtKB/Swiss-Prot.
DT   24-MAY-2005, sequence version 1.
DT   02-SEP-2026, entry version 130.
DE   RecName: Full=DNA topoisomerase 1;
DE            EC=5.6.2.1 {ECO:0000255|PROSITE-ProRule:PRU10130};
DE   AltName: Full=DNA topoisomerase I;
GN   Name=top1; ORFNames=DDB_G0283205;
OS   Dictyostelium discoideum (Social amoeba).
OC   Eukaryota; Amoebozoa; Evosea; Eumycetozoa; Dictyostelia; Dictyosteliales;
OC   Dictyosteliaceae; Dictyostelium.
OX   NCBI_TaxID=44689;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=AX4;
RX   PubMed=15875012; DOI=10.1038/nature03481;
RA   Eichinger L., Pachebat J.A., Gloeckner G., Rajandream M.A., Sucgang R.,
RA   Berriman M., Song J., Olsen R., Szafranski K., Xu Q., Tunggal B.,
RA   Kummerfeld S., Madera M., Konfortov B.A., Rivero F., Bankier A.T.,
RA   Lehmann R., Hamlin N., Davies R., Gaudet P., Fey P., Pilcher K., Chen G.,
RA   Saunders D., Sodergren E.J., Davis P., Kerhornou A., Nie X., Hall N.,
RA   Anjard C., Hemphill L., Bason N., Farbrother P., Desany B., Just E.,
RA   Morio T., Rost R., Churcher C.M., Cooper J., Haydock S., van Driessche N.,
RA   Cronin A., Goodhead I., Muzny D.M., Mourier T., Pain A., Lu M., Harper D.,
RA   Lindsay R., Hauser H., James K.D., Quiles M., Madan Babu M., Saito T.,
RA   Buchrieser C., Wardroper A., Felder M., Thangavelu M., Johnson D.,
RA   Knights A., Loulseged H., Mungall K.L., Oliver K., Price C., Quail M.A.,
RA   Urushihara H., Hernandez J., Rabbinowitsch E., Steffen D., Sanders M.,
RA   Ma J., Kohara Y., Sharp S., Simmonds M.N., Spiegler S., Tivey A.,
RA   Sugano S., White B., Walker D., Woodward J.R., Winckler T., Tanaka Y.,
RA   Shaulsky G., Schleicher M., Weinstock G.M., Rosenthal A., Cox E.C.,
RA   Chisholm R.L., Gibbs R.A., Loomis W.F., Platzer M., Kay R.R.,
RA   Williams J.G., Dear P.H., Noegel A.A., Barrell B.G., Kuspa A.;
RT   "The genome of the social amoeba Dictyostelium discoideum.";
RL   Nature 435:43-57(2005).
CC   -!- FUNCTION: Releases the supercoiling and torsional tension of DNA
CC       introduced during the DNA replication and transcription by transiently
CC       cleaving and rejoining one strand of the DNA duplex. Introduces a
CC       single-strand break via transesterification at a target site in duplex
CC       DNA. The scissile phosphodiester is attacked by the catalytic tyrosine
CC       of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-
CC       enzyme intermediate and the expulsion of a 5'-OH DNA strand. TThe free
CC       DNA strand then rotates around the intact phosphodiester bond on the
CC       opposing strand, thus removing DNA supercoils. Finally, in the
CC       religation step, the DNA 5'-OH attacks the covalent intermediate to
CC       expel the active-site tyrosine and restore the DNA phosphodiester
CC       backbone (By similarity). {ECO:0000250}.
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|PROSITE-
CC         ProRule:PRU10130};
CC   -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000250}.
CC   -!- MISCELLANEOUS: Eukaryotic topoisomerase I and II can relax both
CC       negative and positive supercoils, whereas prokaryotic enzymes relax
CC       only negative supercoils. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the type IB topoisomerase family. {ECO:0000305}.
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DR   EMBL; AAFI02000051; EAL65841.1; -; Genomic_DNA.
DR   RefSeq; XP_639222.1; XM_634130.1.
DR   AlphaFoldDB; Q54RC3; -.
DR   SMR; Q54RC3; -.
DR   FunCoup; Q54RC3; 717.
DR   STRING; 44689.Q54RC3; -.
DR   GlyGen; Q54RC3; 1 site.
DR   PaxDb; 44689-Q54RC3; -.
DR   GeneID; 8623995; -.
DR   KEGG; ddi:DDB_G0283205; -.
DR   dictyBase; DDB_G0283205; top1.
DR   VEuPathDB; AmoebaDB:DDB_G0283205; -.
DR   eggNOG; KOG0981; Eukaryota.
DR   HOGENOM; CLU_009193_1_0_1; -.
DR   InParanoid; Q54RC3; -.
DR   OMA; HRWKEVK; -.
DR   PhylomeDB; Q54RC3; -.
DR   Reactome; R-DDI-4615885; SUMOylation of DNA replication proteins.
DR   PRO; PR:Q54RC3; -.
DR   Proteomes; UP000002195; Chromosome 4.
DR   GO; GO:0005694; C:chromosome; IEA:InterPro.
DR   GO; GO:0005730; C:nucleolus; IBA:GO_Central.
DR   GO; GO:0005634; C:nucleus; ISS:dictyBase.
DR   GO; GO:0003677; F:DNA binding; IEA:InterPro.
DR   GO; GO:0003917; F:DNA topoisomerase type I (single strand cut, ATP-independent) activity; ISS:dictyBase.
DR   GO; GO:0007059; P:chromosome segregation; IBA:GO_Central.
DR   GO; GO:0006260; P:DNA replication; ISS:dictyBase.
DR   GO; GO:0006265; P:DNA topological change; ISS:dictyBase.
DR   CDD; cd00659; Topo_IB_C; 1.
DR   CDD; cd03488; Topoisomer_IB_N_htopoI_like; 1.
DR   FunFam; 1.10.10.41:FF:000001; DNA topoisomerase I; 1.
DR   FunFam; 3.90.15.10:FF:000003; DNA topoisomerase I; 1.
DR   Gene3D; 1.10.132.10; -; 1.
DR   Gene3D; 2.170.11.10; DNA Topoisomerase I, domain 2; 1.
DR   Gene3D; 3.90.15.10; Topoisomerase I, Chain A, domain 3; 1.
DR   Gene3D; 1.10.10.41; Yeast DNA topoisomerase - domain 1; 1.
DR   InterPro; IPR011010; DNA_brk_join_enz.
DR   InterPro; IPR013034; DNA_topo_DNA_db_N_dom1.
DR   InterPro; IPR013030; DNA_topo_DNA_db_N_dom2.
DR   InterPro; IPR001631; TopoI.
DR   InterPro; IPR025834; TopoI_C_dom.
DR   InterPro; IPR014711; TopoI_cat_a-hlx-sub_euk.
DR   InterPro; IPR014727; TopoI_cat_a/b-sub_euk.
DR   InterPro; IPR013500; TopoI_cat_euk.
DR   InterPro; IPR008336; TopoI_DNA-bd_euk.
DR   InterPro; IPR036202; TopoI_DNA-bd_euk_N_sf.
DR   InterPro; IPR013499; TopoI_euk.
DR   InterPro; IPR018521; TopoIB_AS.
DR   InterPro; IPR048045; Topoisomer_I_DNA-bd.
DR   InterPro; IPR051062; Topoisomerase_IB.
DR   PANTHER; PTHR10290:SF3; DNA TOPOISOMERASE 1; 1.
DR   PANTHER; PTHR10290; DNA TOPOISOMERASE I; 1.
DR   Pfam; PF14370; Topo_C_assoc; 1.
DR   Pfam; PF01028; Topoisom_I; 1.
DR   Pfam; PF02919; Topoisom_I_N; 1.
DR   PRINTS; PR00416; EUTPISMRASEI.
DR   SMART; SM00435; TOPEUc; 1.
DR   SUPFAM; SSF56349; DNA breaking-rejoining enzymes; 1.
DR   SUPFAM; SSF56741; Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment; 1.
DR   PROSITE; PS00176; TOPO_IB_1; 1.
DR   PROSITE; PS52038; TOPO_IB_2; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Isomerase; Nucleus; Reference proteome; Topoisomerase.
FT   CHAIN           1..893
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000330481"
FT   DOMAIN          526..893
FT                   /note="Topo IB-type catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01382"
FT   REGION          1..305
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          404..427
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          519..520
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   REGION          582..587
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   REGION          673..675
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   COMPBIAS        33..42
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        91..102
FT                   /note="Low complexity"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        103..114
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        115..126
FT                   /note="Low complexity"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        135..171
FT                   /note="Low complexity"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        184..197
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        208..217
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        218..228
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        237..248
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        271..281
FT                   /note="Basic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        285..294
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        413..427
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        853
FT                   /note="O-(3'-phospho-DNA)-tyrosine intermediate"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01382,
FT                   ECO:0000255|PROSITE-ProRule:PRU10130"
FT   SITE            409
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            457
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            506
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            537
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            594
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            620
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            662
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            721
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            739
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   893 AA;  100612 MW;  DD9BB5F99BF3331E CRC64;
     MEVKQEILTP MKVEKTNGNV PTPPPTTTTT TVMDDDLFDD EASPPQPNKK LKAENGSIKK
     LTPTPKPAPV TPKPTAAVNG KKPIPKKKPV DSSSDSDSSD SSSDSDSDSS DSDSDSSSSD
     SSSSDSDVPK KKPISKIPNK PSGTVSKTSK NSPKTTTTTT TTTTTVKSKP APKVKPEQSS
     SDDSSSDSSD DSSDDSSSDS SSEEEKPKKK PSKKPAAVKK EITVKKETTT TTKKTPVKKE
     VEVKKETKTT TTKKVKKEES DDDGEDEKTT TKKKTTTRKR KLKEEEEGEE EEEEGVNKWW
     DKEDDEDDGT KWTTLIHNGP VFPPAYVPHG IKFMYDGKVV KLTPKQEEVA TFYANYLETD
     HVKKQAFKDN FFKEFKGLLT SEQKEIVKKM DKCDFSHIHT HLKTKKEQRK ARSKEEKDAE
     TAEKKKIQEK HGFATIDGFK EKVGNYMIEP PGLFLGRGQH PKTGMLKQRI MPSDVTLNIG
     EGEVIPPSPI PGEKWKEIVH NNTVTWLAFW RESVNGGFKY VWLAPSSKIK GQADRKKFEV
     ARGLKNCIGD IRKGYQKSFN DESTEKRQLA VALYLIDFLA LRVGNEKGED QADTVGCCSL
     RVEHIKLESN NTITLDFLGK DSMRYLNTVQ IREDAYKVLK TFVKGKKPTD LLFDSLTVTQ
     LNNHLKKQMT GLSAKVFRTY NASITLQKEL DKMDTKEFQS IDEKILFYNR CNREVAILCN
     HQKAPPKNLA ETMSKIDEKI QELRDLQDLC RIKIGKTPKS QQEDIESREA ERLPKLIQLA
     ITNKKDKDKE KTDKEISFDV KAAFEKSRTL PDAKGKIKEK IAKYEEQIKK QEILKTGKDE
     LKTVALGTSK INYLDPRITV AWCKKNKVPV DKIFTKSLRD KFPWSDVGTD YIF
//