| Title |
Overexpression of Outer Membrane Protein OprT and Increase of Membrane Permeability in phoU Mutant of Toluene-Tolerant Bacterium Pseudomonas putida GM730 |
| Author |
Kyunghee Lee1, Juna Jung2, Kwang Kim1, Dongwon Bae3, and Dongbin Lim2* |
| Address |
1Division of Applied Life Science (BK21 program), Gyeongsang National University, Jinju 660-701, Republic of Korea, 2Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Republic of Korea, 3Central Instrument Facility, Gyeongsang National University, Jinju 660-701, Republic of Korea |
| Bibliography |
Journal of Microbiology, 47(5),557-562, 2009,
|
| DOI |
|
| Key Words |
PhoU, P. putida, membrane permeability, outer membrane protein OprT, toluene |
| Abstract |
Eight toluene-sensitive mutants were previously isolated from the toluene-tolerant bacterium Pseudomonas putida GM730. One of these mutants was TOS6, in which Tn5 had been inserted into phoU. Susceptibility to multiple antibiotics, as well as toluene sensitivity, was increased in the phoU mutant of P. putida GM730. We compared the outer membrane proteins from the phoU mutant and wild-type via two-dimensional gel electrophoresis. A 45 kDa protein was dramatically overexpressed as the result of phoU inactivation, and this protein was identified by peptide mass fingerprinting and microsequencing as a conserved hypothetical protein consisting of 414 amino acids. The protein, designated as OprT, harbors a signal sequence and extended β-sheets, both of which are features common to the bacterial porins. The rate of ethidium bromide accumulation in TOS6 was higher than in GM730, which indicates that the TOS6 membranes may be more permeable to ethidium bromide than are the membranes of GM730. We propose that the toluene sensitivity
and increased antibiotic susceptibility observed in the phoU mutant may be attributable to increased membrane permeability. |
