Annotations: 1CY1

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1cy1a_	Multi-domain proteins (alpha and beta)	Prokaryotic type I DNA topoisomerase	Prokaryotic type I DNA topoisomerase	Prokaryotic type I DNA topoisomerase	DNA topoisomerase I, 67K N-terminal domain	(Escherichia coli K-12 ) [TaxId: 83333 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	Prokaryotic type I DNA topoisomerase clamp domain-like	8036554	3001789	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Toprim domain-like	8055743	3000737	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	CSD	e1cy1A1	A: a/b three-layered sandwiches	X: Phage tail fiber protein trimerization domain	H: beta-Prism I	T: beta-Prism I	F: CSD	ECOD (v294.1)
A	Phage_CII	e1cy1A2	A: a/b three-layered sandwiches	X: ETN0001 domain-like	H: YozE-like	T: Ribbon-helix-helix	F: Phage_CII	ECOD (v294.1)
A	TOP6A-Spo11_Toprim	e1cy1A4	A: a/b three-layered sandwiches	X: HTH	H: HTH	T: winged helix domain	F: TOP6A-Spo11_Toprim	ECOD (v294.1)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.40.50.140	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold		CATH (4.3.0)
A	1.10.460.10	Mainly Alpha	Orthogonal Bundle	Topoisomerase I	domain 2	CATH (4.3.0)
A	2.70.20.10	Mainly Beta	Distorted Sandwich	Topoisomerase I	domain 3	CATH (4.3.0)
A	1.10.290.10	Mainly Alpha	Orthogonal Bundle	Topoisomerase I	domain 4	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF01131	DNA topoisomerase (Topoisom_bac)	DNA topoisomerase	-	Family
A	PF01751	Toprim domain (Toprim)	Toprim domain	-	Family

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	DNA TOPOISOMERASE I	DNA binding binding nucleic acid binding RNA topoisomerase activity nucleic acid conformation isomerase activity isomerase activity catalytic activity, acting on RNA catalytic activity, acting on a nucleic acid macromolecular conformation isomerase activity catalytic activity DNA topoisomerase type I (single strand cut, ATP-independent) activity catalytic activity, acting on DNA DNA topoisomerase activity cation binding DNA binding binding nucleic acid binding RNA topoisomerase activity nucleic acid conformation isomerase activity isomerase activity catalytic activity, acting on RNA catalytic activity, acting on a nucleic acid macromolecular conformation isomerase activity catalytic activity DNA topoisomerase type I (single strand cut, ATP-independent) activity catalytic activity, acting on DNA DNA topoisomerase activity cation binding transition metal ion binding zinc ion binding ion binding metal ion binding small molecule binding	cellular process cell cycle chromosome segregation cell cycle process chromosome organization primary metabolic process DNA conformation change DNA metabolic process nucleic acid metabolic process cellular component organization nucleobase-containing compound metabolic process DNA topological change organelle organization metabolic process cellular process cell cycle chromosome segregation cell cycle process chromosome organization primary metabolic process DNA conformation change DNA metabolic process nucleic acid metabolic process cellular component organization nucleobase-containing compound metabolic process DNA topological change organelle organization metabolic process cellular component organization or biogenesis macromolecule metabolic process	cellular anatomical structure intracellular anatomical structure cytoplasm cytosol intracellular organelle organelle membraneless organelle intracellular membraneless organelle chromosome

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR013498	DNA topoisomerase, type IA, zn finger	Domain
A	IPR003601	DNA topoisomerase, type IA, domain 2	Domain
A	IPR028612	DNA topoisomerase I, type IA	Family
A	IPR000380	DNA topoisomerase, type IA	Family
A	IPR013826	DNA topoisomerase, type IA, central region, subdomain 3	Homologous Superfamily
A	IPR006171	TOPRIM domain	Domain
A	IPR005733	DNA topoisomerase I, bacterial-type	Family
A	IPR013497	DNA topoisomerase, type IA, central	Domain
A	IPR003602	DNA topoisomerase, type IA, DNA-binding domain	Domain
A	IPR049330	Topoisomerase I, zinc finger	Domain
A	IPR013263	DNA topoisomerase I, zinc ribbon-like, bacterial-type	Domain
A	IPR023405	DNA topoisomerase, type IA, core domain	Homologous Superfamily
A	IPR013825	DNA topoisomerase, type IA, central region, subdomain 2	Homologous Superfamily
A	IPR023406	DNA topoisomerase, type IA, active site	Active Site
A	IPR034149	DNA topoisomerase 1, TOPRIM domain	Domain
A	IPR013824	DNA topoisomerase, type IA, central region, subdomain 1	Homologous Superfamily

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.