Effect of Mutation in Efflux Pump Regulatory Protein (MexR) of Pseudomonas aeruginosa: A Bioinformatic Study

Pseudomonas aeruginosa is an important non-fermenting gram-negative hospital-acquired pathogen. Treatment of P. aeruginosa infections has become more challenging due to overexpression of efflux pumps. The aim of the present study was to apply in silico analysis to evaluate the structure of the efflux pump regulatory protein, MexR, and impact of mutation on its stability and function.

Different bioinformatics tools including EXPASY, PROTEER, TECCOFFE, iStable, I-Mutant 2, STRING, ESPript, GOR IV, and PDB were used in the study.

Aliphatic and instability indices were 104.15, and 46.52, respectively, indicating that the protein has a relatively short half-life. Most mutations decreased protein stability. Twenty-four mutations were identified as deleterious, with negative impact on the protein’s function.

Determination of structure, variability, and function of MexR could be useful for modeling of treatment and control of multidrug resistant P. aeruginosa, with overexpressed efflux pump. We found that MexR is a relatively unstable and conserved protein and the majority of mutations decrease its stability.