Bacterial Outer Membranes and Interactions with Membrane Proteins

Wonpil Im
Departments of Biological Sciences and Bioengineering, Lehigh University
Thursday, February 20, 2020
10:00 am
NS2 1201
The outer membrane of gram-negative bacteria is a unique asymmetric membrane bilayer that is composed of phospholipids in the inner leaflet and lipopolysaccharides (LPS) in the outer leaflet. Its function as a selective barrier is crucial for the survival of bacteria in many distinct environments, and it also renders gram-negative bacteria more resistant to antibiotics than their gram-positive counterparts. LPS comprises three regions: lipid A, core oligosaccharide, and O-antigen polysaccharide. In this talk, I will present our ongoing efforts to understanding various bacterial outer membranes and their interactions with outer membrane proteins. In addition, I will also present other research projects in my lab, such as the CHARMM-GUI development, a local structure-centric bioinformatics for drug development, and structure-based computational glycobiology.
Gram-negative bacterial outer membrane molecular complexity. This image illustrates a typical E. coli outer membrane. The bilayer is composed of (from the top, external leaflet) glycosylated amphipathic molecules known as lipopolysaccharide (LPS) consisting of an O-antigen polysaccharide, a core oligosaccharide, and lipid A and (the bottom, periplasmic leaflet) consisting of various phospholipid molecules. The cyan atoms interspersed with the core oligosaccharides are calcium atoms, which immobilize the membrane by mediating the cross-linking electrostatic interaction network. K+ and Cl- ions are magenta and green spheres.
Jun Allard