Computer simulation of the rough lipopolysaccharide membrane of Pseudomonas aeruginosa

Lipopolysaccharides (LPSs) form the major constituent of the outer membrane of Gram-negative bacteria, and are believed to play a key role in processe s that govern microbial metal binding, microbial adsorption to mineral surf aces, and microbe-mediated oxidation/reduction reactions at the bacterial e xterior surface. A computational modeling capability is being developed for the study of geochemical reactions at the outer bacterial envelope of Gram -negative bacteria. A molecular model for the rough LPS of Pseudomonas aeru ginosa has been designed based on experimentally determined structural info rmation. An electrostatic model was developed based on Hartree-Fock SCF cal culations of the complete LPS molecule to obtain partial atomic charges. Th e exterior of the bacterial membrane was assembled by replication of a sing le LPS molecule and a single phospholipid molecule. Molecular dynamics simu lations of the rough LPS membrane of P. aeruginosa were carried out and tra jectories were analyzed for the energetic and structural factors that deter mine the role of LPS in processes at the cell surface.