Premium
Pseudomonas aeruginosa encodes a functional type IB topoisomerase
Author(s) -
Jain Teesta,
Grove Anne
Publication year - 2006
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.20.5.a910-b
Subject(s) - topoisomerase , dna supercoil , dna , biology , pseudomonas aeruginosa , biochemistry , escherichia coli , microbiology and biotechnology , chemistry , gene , dna replication , genetics , bacteria
Pseudomonas aeruginosa encodes a putative topoisomerase with sequence similarity to the type IB topoisomerase enzyme from vaccinia virus. The 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 active site are conserved, notably Tyr292 which would be predicted to form the covalent bond to DNA. The gene encoding the P. aeruginosa topoisomerase IB was cloned and purified and from Escherichia coli . It was approximately 36KDa. The enzyme relaxes supercoiled DNA, while a mutant of P. aeruginosa containing a Tyr (292) to Phe substitution at the active site was found to be catalytically inert. This is consistent with the role of Tyr in forming the covalent intermediate. Like vaccinia topoisomerase, P. aeruginosa relaxes DNA in the absence of ATP. Unlike vaccinia topoisomerase, P. aeruginosa topoisomerase does not relax supercoiled without MgCl 2 (or MnCl 2 ) present. Also, high concentration of NaCl is not able to substitute for MgCl 2 as seen for vaccinia topoisomerase. Data shows that P. aeruginosa encodes a functional topoisomerase with significant similarity to the type IB enzyme encoded by poxviruses. This enzyme may constitute a major target for specific inhibitors. Research Support: National Science Foundation