Title:  Regulatory Mechanisms of Lipopolysaccharide Synthesis in Escherichia coli

Speaker: Wei Mi, Ph.D.

Host: Maofu Liao, Ph.D.

Time: 09:00-10:30, April 2nd, 2024

Venue: The Learning Studio(Starbucks, 2nd Floor)

Abstract: 

The outer membrane (OM) of Gram-negative bacteria forms a permeability barrier to protect the cell against both large polar molecules and hydrophobic agents, rendering Gram-negative bacteria more resistant to antibiotics than their Gram-positive cousins. The OM derives its special permeability from its asymmetric bilayer structure with lipopolysaccharide (LPS) in the surface-exposed outer leaflet and phospholipids in the leaflet facing the periplasm. The Biosynthesis of LPS is tightly regulated to maintain an optimal ratio with phospholipids and thus OM integrity. We use in vitro assays with purified components to elucidate underlying molecular mechanisms and use single particle cryo-electron microscopy (cryoEM) to understand the structural basis.

Brief introduction of the speaker:

Wei Mi obtained his PhD degree in structural biology at Peking University, Beijing, China. Fascinated by the structures of membrane proteins, he came to the US and received postdoctoral training at Purdue University, the University of Washington, and Harvard Medical School (HMS). At HMS, he joined the laboratory of Dr. Maofu Liao and used single particle cryo-electron microscopy (Cryo-EM) to determine structures of ATP-binding cassette transporters in a lipid bilayer environment. In 2019, Dr Mi joined the Department of Pharmacology at Yale University School of Medicine as an assistant professor with a secondary appointment in the Department of Molecular Biophysics and Biochemistry. The focus of his research is to dissect the mechanisms of membrane proteins involved in lipopolysaccharide (LPS) synthesis and regulation with genetic, biochemical, and structural approaches.