Article info Vol. 6  No. 2   pp.  42 ~ 45
Title Purification and preliminary analysis of the regulatory domain of MexT from Pseudomonas aeruginosa, a LysR-type transcriptional activator of the MexEF-OprN multidrug efflux pump
Authors Suhyeon Kim1, Jinsook Ahn and Nam-Chul Ha1*
Institutions 1Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, Republic of Korea *Correspondence: hanc210@snu.ac.kr
Abstract Pseudomonas aeruginosa is an opportunistic pathogen, and have multiple multidrug efflux pumps. The MexEF-OprN multidrug efflux system is overexpressed in nfxC-type mutants and give resistance to quinolones, chloramphenicol and trimethoprim. A LysR-type transcriptional activator, MexT, is the major activator of this efflux system. Although the activity of MexT is regulated in response to the cellular redox state, the ligand and activation mechanism remain unknown yet. MexT consists of the N-terminal DNA binding domain and the C-terminal regulatory domain that contains the ligand binding site. In this study, we overproduced and purified the regulatory domain of MexT from P. aeruginosa and obtained the crystals suitable for the structural study. The crystal diffracted X-ray to 2.3 Å resolution, revealing that the crystals belong to space group P212121, with unit cell parameters a = 65.7, b = 108.5, and c = 109.1 Å. The cell content analysis suggested that 3 or 4 molecules are contained in the asymmetric unit. To solve the phasing problem, growing of the Se- Met substituted crystals are underway. This structure will give insight into the molecular mechanism of the activation of MexT in the presence of antibiotics.