Molecular Insights into Function and Competitive Inhibition of Pseudomonas aeruginosa Multiple Virulence Factor Regulator

• DOI: 10.1128/mbio.02158-17
• Publication Date: 2018-01-15T08:34:59Z
• Authors: Tomoe Kitao; Francois Lepine; Seda Babloudi; Frederick Walte; Stefan Steinbacher; Klaus Maskos; Michael Blaesse; Michele Negri; Michael Pucci; Bob Zahler; Antonio Felici; Laurence G. Rahme
• Keywords: Virulence factor

ABSTRACT New approaches to antimicrobial drug discovery are urgently needed combat intractable infections caused by multidrug-resistant (MDR) bacteria. M ultiple v irulence f actor r egulator (MvfR or PqsR), a Pseudomonas aeruginosa quorum sensing transcription factor, regulates functions important in both acute and persistent infections. Recently identified non-ligand-based benzamine-benzimidazole (BB) inhibitors of MvfR suppress P. mice without perturbing bacterial growth. Here, we elucidate the crystal structure ligand binding domain (LBD) complex with one potent BB inhibitor, M64. Structural analysis indicated that M64 binds, like native ligands, hydrophobic cavity. A hydrogen bond pi interaction were found be for MvfR-M64 affinity. Surface plasmon resonance demonstrated is competitive inhibitor MvfR. Moreover, protein engineering approach revealed Gln194 Tyr258 critical between Random mutagenesis full-length single-amino-acid substitution, I68F, at DNA linker confers insensitivity. In presence M64, I68F but not wild-type (WT) retained ability. Our findings strongly suggest promotes conformational change mutation may compensate this change, indicating allosteric inhibition. This work provides new insights into molecular mechanism function inhibition could aid optimization anti-MvfR compounds improve our understanding regulation. IMPORTANCE an opportunistic Gram-negative pathogen causes serious acute, persistent, relapsing pathogen. The factor We used recently perform structural studies reveal would benefit compounds. Altogether, results reported here provide detailed mechanistic domains chemical, pharmacological, safety properties antagonist series.