Annotations: 1D6M

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1d6ma_	Multi-domain proteins (alpha and beta)	Prokaryotic type I DNA topoisomerase	Prokaryotic type I DNA topoisomerase	Prokaryotic type I DNA topoisomerase	DNA topoisomerase III	(Escherichia coli ) [TaxId: 562 ],	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	8033735	3001789	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Toprim domain-like	8055739	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	Topoisom_bac_2nd	e1d6mA1	A: beta barrels	X: LigT-like	H: Prokaryotic type I DNA topoisomerase beta-barrel domain (From Topology)	T: Prokaryotic type I DNA topoisomerase beta-barrel domain	F: Topoisom_bac_2nd	ECOD (1.6)
A	Topoisom_bac_3rd	e1d6mA2	A: alpha arrays	X: HTH	H: HTH	T: winged	F: Topoisom_bac_3rd	ECOD (1.6)
A	Topoisom_bac_1st_1	e1d6mA3	A: alpha arrays	X: HTH	H: HTH	T: winged	F: Topoisom_bac_1st_1	ECOD (1.6)
A	Toprim	e1d6mA4	A: a/b three-layered sandwiches	X: HAD domain-like	H: HAD domain-related	T: Toprim domain	F: Toprim	ECOD (1.6)

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 III	cation binding magnesium ion binding ion binding binding metal ion binding small molecule binding isomerase activity DNA topoisomerase type I (single strand cut, ATP-independent) activity catalytic activity, acting on DNA DNA topoisomerase activity catalytic activity, acting on a nucleic acid catalytic activity sequence-specific DNA binding DNA binding cation binding magnesium ion binding ion binding binding metal ion binding small molecule binding isomerase activity DNA topoisomerase type I (single strand cut, ATP-independent) activity catalytic activity, acting on DNA DNA topoisomerase activity catalytic activity, acting on a nucleic acid catalytic activity sequence-specific DNA binding DNA binding sequence-specific single stranded DNA binding organic cyclic compound binding single-stranded DNA binding nucleic acid binding	chromosome separation cellular process cell cycle chromosome segregation cell cycle process cellular response to stimulus response to stimulus primary metabolic process DNA metabolic process nucleic acid metabolic process nucleobase-containing compound metabolic process cellular response to stress DNA damage response response to stress chromosome separation cellular process cell cycle chromosome segregation cell cycle process cellular response to stimulus response to stimulus primary metabolic process DNA metabolic process nucleic acid metabolic process nucleobase-containing compound metabolic process cellular response to stress DNA damage response response to stress metabolic process macromolecule metabolic process DNA repair DNA-templated DNA replication DNA replication chromosome organization DNA conformation change cellular component organization DNA topological change organelle organization cellular component organization or biogenesis DNA recombination	intracellular organelle intracellular anatomical structure organelle intracellular non-membrane-bounded organelle replication fork chromosome cytoplasmic replication fork cellular anatomical entity cytoplasm non-membrane-bounded organelle

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR013497	DNA topoisomerase, type IA, central	Domain
A	IPR003602	DNA topoisomerase, type IA, DNA-binding domain	Domain
A	IPR023405	DNA topoisomerase, type IA, core domain	Homologous Superfamily
A	IPR013825	DNA topoisomerase, type IA, central region, subdomain 2	Homologous Superfamily
A	IPR003601	DNA topoisomerase, type IA, domain 2	Domain
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	IPR005738	DNA topoisomerase III	Family
A	IPR023406	DNA topoisomerase, type IA, active site	Active Site
A	IPR034144	DNA topoisomerase 3-like, TOPRIM domain	Domain
A	IPR013824	DNA topoisomerase, type IA, central region, subdomain 1	Homologous Superfamily

Structure Motif Annotation: Mechanism and Catalytic Site Atlas M-CSA Database Homepage

Chains	Enzyme Name	Description	Catalytic Residues
A	DNA topoisomerase (type III) M-CSA #64	Topoisomerases catalyse the winding and unwinding of super-coiled DNA, a process vital during DNA replication, transcription and repair. Type I topoisomerases reversibly cut one strand of the DNA helix, and can only relax supercoils. Analysis of sequence and mutagenesis data indicates that the type Ia topoisomerases (those found in prokaryotes, and the example given here) may be related to the major family of type II topoisomerases (found in all life apart from some archaea). Type II topoisomerases cut both strands and can either relax or tighten super-coils, but require ATP hydrolysis for catalytic turnover. All topoisomerases recorded form an intermediate with a tyr-DNA covalent bond during catalysis.	Defined by 6 residues: GLU:A-7LYS:A-8ASP:A-103ASP:A-105TYR:A-328ARG:A-330 \| Explore in 3D: M-CSA Motif Definition Search M-CSA Motif EC: 5.99.1.2 (PDB Primary Data) Search M-CSA Motif + EC 5.99.1.2 EC: 5.6.2.1 (UniProt) Search M-CSA Motif + EC 5.6.2.1

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.