December 6, Tue 2011
1:00 pm, MRB 200 Conference Room
Dr. Lukas Tamm
University of Virginia, Molecular Physiology and Biological Physics
Structure, Function, and Antibiotic Resistance of the Outer Membrane of Pseudomonas Aeruginosa
Pseudomonas aeruginosa is a major nosocomial pathogen that infects cystic fibrosis andimmunocompromised patients. The impermeability of the P. aeruginosa outer membrane contributes substantially to the notorious antibiotic resistance of this human pathogen. This impermeability is partially imparted by the outer membrane protein H (OprH). I will describe the structure of OprH that was solved by solution NMR in a lipid environment. The eight-stranded βeta-barrel protein interacts with four extracellular dynamic loops with lipopolysaccharide (LPS) – an interaction that can be seen and localized to specific residues on the protein by NMR. OprH-LPS interactions are thought to contribute in a major way to the toughness and antibiotic resistance of the outer membrane under low divalent cation conditions. OprG is another protein of the outer membrane of P. aeruginosa that is believed to form a channel for the uptake of hydrophobic compounds. Ongoing structural and functional studies of this protein will also be described.