1LNW

CRYSTAL STRUCTURE OF THE MEXR REPRESSOR OF THE MEXAB-OPRM MULTIDRUG EFFLUX OPERON OF PSEUDOMONAS AERUGINOSA

Summary for 1LNW

• Entry DOI: 10.2210/pdb1lnw/pdb
• Descriptor: Multidrug resistance operon repressor (2 entities in total)
• Functional Keywords: mexr, repressor, dna binding protein, regulator of mexrab-oprm operon, transcription repressor
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 8
• Total formula weight: 137776.22

Authors

Lim, D.C.,Poole, K.,Strynadka, N.C.J. (deposition date: 2002-05-03, release date: 2002-09-11, Last modification date: 2024-10-16)

Primary citation

Lim, D.,Poole, K.,Strynadka, N.C.
Crystal structure of the MexR repressor of the mexRAB-oprM multidrug efflux operon of Pseudomonas aeruginosa.
J.Biol.Chem., 277:29253-29259, 2002

PubMed Abstract: MexR is a member of the MarR family of bacterial transcriptional regulators and is the repressor for the MexAB-OprM operon, which encodes a tripartite multidrug efflux system in Pseudomonas aeruginosa. Mutations in MexR result in increased resistance to multiple antibiotics due to overexpression of this efflux system. We have determined the crystal structure of MexR to 2.1-A resolution in the absence of effector. The four copies of the MexR dimer in the asymmetric unit are observed in multiple conformations. Analysis of these conformational states in the context of a model of the MexR-DNA complex proposed in this study suggests that an effector-induced conformational change may inhibit DNA binding by reducing the spacing of the DNA binding domains. The inhibited conformation is exhibited by one of the four MexR dimers, which contains an ordered C-terminal tail from a neighboring monomer inserted between its DNA binding domains and which we propose may resemble the MexR-effector complex. Our results indicate that MexR may differ from the other described member of this family, MarR, in the nature of its effector, mode of DNA binding, and mechanism of regulation.

PubMed: 12034710
DOI: 10.1074/jbc.M111381200

Experimental method

X-RAY DIFFRACTION (2.1 Å)