P46155 (TOP1_ENTAE) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
DNA topoisomerase 1
EC=5.99.1.2

Alternative name(s):
DNA topoisomerase I
Omega-protein
Relaxing enzyme
Swivelase
Untwisting enzyme

Gene names

Name:

topA

Organism

Enterobacter aerogenes (Aerobacter aerogenes)

Taxonomic identifier

548 [NCBI]

Taxonomic lineage

cellular organisms › Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Enterobacter

Protein attributes

Sequence length	18 AA.
Sequence status	Fragment.
Protein existence	Inferred from homology

General annotation (Comments)

Function	Releases the supercoiling and torsional tension of DNA, which is introduced during the DNA replication and transcription, by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand, thus removing DNA supercoils. Finally, in the religation step, the DNA 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone By similarity.
Catalytic activity	ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
Subunit structure	Monomer By similarity.
Sequence similarities	Belongs to the type IA topoisomerase family.

Ontologies

Keywords
Ligand	ATP-binding DNA-binding Nucleotide-binding
Molecular function	Isomerase Topoisomerase
Gene Ontology (GO)
Biological_process	DNA topological change Inferred from electronic annotation. Source: InterPro
Cellular_component	chromosome Inferred from electronic annotation. Source: InterPro
Molecular_function	ATP binding Inferred from electronic annotation. Source: UniProtKB-KW DNA topoisomerase type I activity Inferred from electronic annotation. Source: EC DNA topoisomerase type II (ATP-hydrolyzing) activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	‹1 – 18	›18	DNA topoisomerase 1		PRO_0000145152
Experimental info
	Non-terminal residue	1	1

Sequences

	Sequence		Length	Mass (Da)
	P46155 [UniParc]. Last modified November 1, 1995. Version 1. Checksum: 8C1C81238FF0EFA4	FASTA	18	2,043
	10 ATGWSAFFID GKWTEAKK

References

[1]

"Characterization of the CysB protein of Klebsiella aerogenes: direct evidence that N-acetylserine rather than O-acetylserine serves as the inducer of the cysteine regulon." Lynch A.S., Tyrrell R., Smerdon S.J., Briggs G.S., Wilkinson A.J. Biochem. J. 299:129-136(1994) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: NCTC 418 / ATCC 15380.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X78729 Genomic DNA. No translation available.
3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
HAMAP	MF_00952. Topoisom_1_prok.
InterPro	IPR013263. TopoI_Znr_bac. [Graphical view]
Pfam	PF08272. Topo_Zn_Ribbon. 1 hit. [Graphical view]
PROSITE	PS00396. TOPOISOMERASE_I_PROK. Partial match. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

TOP1_ENTAE

Accession

Primary (citable) accession number: P46155

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1995
Last sequence update:	November 1, 1995
Last modified:	May 1, 2013
This is version 47 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program