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Pseudomonas aeruginosa encodes a functional type IB topoisomerase
Author(s) -
Jain Teesta,
Roper Ben,
Grove Anne
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a659
Subject(s) - topoisomerase , dna supercoil , biology , dna , pseudomonas aeruginosa , microbiology and biotechnology , topoisomerase iv , escherichia coli , biochemistry , gene , dna gyrase , genetics , dna replication , bacteria
Pseudomonas aeruginosa is an opportunistic pathogen which is capable of causing disease in plants as well as animals. P. aeruginosa bacteremia is a serious and potentially fatal condition in cancer patients. P. aeruginosa encodes a putative topoisomerase with sequence similarity to the type IB enzyme from Vaccinia virus. This topoisomerase binds duplex DNA and forms a covalent protein DNA complex where the active site tyrosine attacks a phosphodiester bond on one DNA strand. Residues in the P. aeruginosa topoisomerase IB (PAT) active site are conserved, notably Tyr292 which would be predicted to form the covalent bond to DNA. The gene encoding PAT was cloned and protein purified from Escherichia coli . PAT relaxes supercoiled DNA, while the mutant enzyme (Y292F) lacks activity. Also Topo‐(81–333), a truncated derivative that lacks the N‐terminal domain, performs the same repertoire of reactions as the full length topoisomerase. Like Vaccinia topoisomerase, P. aeruginosa relaxes DNA in the absence of ATP. Unlike Vaccinia topoisomerase, PAT does not relax supercoiled DNA without MgCl 2 present. Also, high concentration of NaCl is not able to substitute for MgCl 2 . This enzyme may constitute a major target for inhibitors.