topA

topA
168

DNA topoisomerase I

Locus
BSU_16120
Molecular weight
78.89 kDa
Isoelectric point
9.02
Protein length
691 aaSequenceBlast
Gene length
2076 bpSequenceBlast
Function
relaxation of negatively supercoiled DNA behind RNA polymerase
Product
DNA topoisomerase I
Essential
quasi
E.C.
5.99.1.2
Synonyms
topA, topI
Outlinks
BsubCyc SubtiList UniProt STRING Genoscapist PaperBLAST

Genomic Context

Categories containing this gene/protein

List of homologs in different organisms, belongs to COG0551 (Galperin et al., 2021)

This gene is a member of the following regulons

Gene
Coordinates
1,683,661  1,685,736
Phenotypes of a mutant
the mutant tends to acquire suppressor mutations that result in improved growth PubMed
essential PubMed
non-essential according to PubMed, but only one resistance cassette was possible
quasi-essential, deletion of topA results in the immediate acquisition of suppressor mutations that result in overexpression of ParE-ParC PubMed
The protein
Catalyzed reaction/ biological activity
relaxation of negatively supercoiled DNA
ATP-independent breakage of single-stranded DNA, followed by passage and rejoining (according to UniProt)
Protein family
Type IA topoisomerase family (together with TopB)(according to UniProt)
Domains
N-terminal TOPRIM domain (aa 3-114) PubMed
Structure
4RUL (PDB) (from E. coli, 40% identity) PubMed
P39814 (AlphaFold)
Paralogous protein(s)
TopB
Expression and Regulation
Operons
Genes
sucC-sucD-dprA-topA
Description
PubMed
Regulation
repressed by glucose (2.4-fold) (CcpA) PubMed
expression is heterogeneous PubMed
Regulatory mechanism
CcpA: repression, PubMed, in ccpA regulon
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sucC→topA

2025-03-17 21:02:13

Jstuelk

93

167fd8fae94fab138af8eabe6101bc58adfb0921

2BC79D48E345B722DDAE396E448CF1DB3AAB049C

Genes
topA
Description
PubMed
Additional information
translation is likely to require Efp due to the presence of several consecutive proline residues PubMed
Open in new tab

topA

2025-03-28 11:36:02

ghost

83

62af9b23a6fb353a327c6cc32683d6f9a2d0797d

5EF949E4EDB0EB3FFA1798FF0A2E0AC5DF0A72DB

Biological materials
Mutant
BKK16120 (ΔtopA::kan  trpC2) available at BGSC,  PubMed, upstream reverse: _UP1_CATTTTCATCCCCCTCAAGA,  downstream forward: _UP4_TAGCGGTGAGCAGGGTCTTG
GP1963 (ΔtopA::aphA3 (citB-alsT)16) PubMed
Expression vectors
pGP2060: IPTG inducible expression, purification in E. coli with N-terminal Strep-tag, in pGP172, available in Jörg Stülke's lab
References
Reviews
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Original Publications
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41199C76DF8CA804B7B8878D61228B9542A96AE4

Page visits: 5114

Time of last update: 2025-04-08 19:58:53

Author of last update: Jstuelk