(178p) Virtual Screening of Quenchers for the Signal 3-Hydroxypalmitic Acid Methyl Ester in Ralstonia Solanacearum

Ralstonia solanacearum, a widely distributed bacterial phytopathogen, causes a lethal wilting disease in more than 200 plants species. The expression of virulence and pathogenicity genes in R. solanacearum is controlled by a complex system that senses key environmental cues and triggers global shifts of gene expression. A central node in the control network is the quorum sensing (QS) system. Diverse kinds of QS signals have been reported in nature. Molecules in the group of N-acyl-homoserine lactones (AHLs) are the most commonly reported type of QS signals in bacteria. Although R. solanacearum exhibits an AHL-dependent system, the expression of virulence factors is AHL-independent. The chemical signal that controls the levels of virulence factors via quorum sensing in R. solanacearum is 3-Hydroxypalmitic acid methyl ester (3-OH PAME). In this work we used a computational approach to identify lipases with the potential ability to act as quenchers of the molecule 3-OH PAME. First we predicted de 3D structure of 3-OH PAME by geometry optimization using AMBER as a force field. Then we assess the capacity of the Candida antarctica's lipase B of being a quencher of 3-OH through molecular docking. To accomplish this, we evaluated the protein-ligand interaction between lipase B, N-Hexylphosphonate ethyl ester (Hee commun ligand) and 3-OH PAME. Molecular dynamics help to estimate the stability of the protein-ligand complexes obtained. Results obtained by this computational approach showed that lipase B could be a potential quencher of 3-OH PAME. We obtained through molecular dynamics a global minimum energy for 3-OH PAME of 3.827768 kcal/mol in contrast to its initial energy of 10.376802 kcal/mol. We also assess the kinetic and potential energies and the distance between atoms of 3-OH PAME and of the protein-ligand complex.