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Mol Cells. 2019 Nov 14. doi: 10.14348/molcells.2019.0168. [Epub ahead of print]

Crystal Structure of the Regulatory Domain of MexT, a Transcriptional Activator of the MexEFOprN Efflux Pump in Pseudomonas aeruginosa.

Author information

1
Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Center for Food and Bioconvergence, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.
2
Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Korea.
3
Present address: KoBioLabs, Inc., Seoul 08826, Korea.

Abstract

The Gram-negative opportunistic pathogen, Pseudomonas aeruginosa, has multiple multidrug efflux pumps. MexT, a LysR-type transcriptional regulator, functions as a transcriptional activator of the MexEF-OprN efflux system. MexT consists of an N-terminal DNA-binding domain and a C-terminal regulatory domain (RD). Little is known regarding MexT ligands and its mechanism of activation. We elucidated the crystal structure of the MexT RD at 2.0 Å resolution. The structure comprised two protomer chains in a dimeric arrangement. MexT possessed an arginine-rich region and a hydrophobic patch lined by a variable loop, both of which are putative ligand-binding sites. The three-dimensional structure of MexT provided clues to the interacting ligand structure. A DNase I footprinting assay of full-length MexT identified two MexT-binding sequence in the mexEF-oprN promoter. Our findings enhance the understanding of the regulation of MexT-dependent activation of efflux pumps.

KEYWORDS:

MexT; Pseudomonas aeruginosa; antibiotic resistance; crystal structure; lysR-type transcriptional regulator

PMID:
31722511
DOI:
10.14348/molcells.2019.0168
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