Compensatory increase in ahpC gene expression and its role in protecting Burkholderia pseudomallei against reactive nitrogen intermediates.

Suvit Loprasert, Ratiboot Sallabhan, Wirongrong Whangsuk, Skorn Mongkolsuk

Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand. suvit@tubtim.cri.or.th

Archives of microbiology 2003 Dec

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In the human pathogen Burkholderia pseudomallei, katG encodes the antioxidant defense enzyme catalase-peroxidase. Interestingly, a B. pseudomallei mutant, disrupted in katG, is hyperresistant to organic hydroperoxide. This hyperresistance is due to the compensatory expression of the alkyl hydroperoxide reductase gene ( ahpC) and depends on a global regulator OxyR. The KatG-deficient mutant is also highly resistant to reactive nitrogen intermediates (RNI). When overproduced, the B. pseudomallei AhpC protein, protected cells against killing by RNI. The levels of resistance to both organic peroxide and RNI returned to those of the wild-type when the katG mutant was complemented with katG. These studies establish the partially overlapping defensive activities of KatG and AhpC.

Citation

Suvit Loprasert, Ratiboot Sallabhan, Wirongrong Whangsuk, Skorn Mongkolsuk. Compensatory increase in ahpC gene expression and its role in protecting Burkholderia pseudomallei against reactive nitrogen intermediates. Archives of microbiology. 2003 Dec;180(6):498-502