November 8, Tue 2011
1:00 pm, MRB 200 Conference Room
Dr. Francisca M. Marassi
Structural studies of Membrane Proteins in Phospholipid Bilayers
Membrane protein structures and functions are regulated by their physical interactions with the surrounding lipids, and NMR is unique in its ability to provide high-resolution information in lipid environments that closely resemble the cellular membranes. Solid-state NMR experiments with proteins in oriented bilayers, and solution NMR experiments with proteins in weakly oriented micelles, provide high-resolution orientation-dependent restraints that can be combined for protein structure determination and refinement. As previously observed for a-helical membrane proteins, the NMR spectra of b-barrel membrane proteins in lipid bilayers exhibit characteristic patterns that reflect both protein structure and intra-membrane orientation. Integral membrane proteins regulate major cellular processes in health and disease, including transport, signaling, secretion, adhesion, pathogenesis, and apoptosis, and therefore, represent important targets for structural and functional characterization. Results are presented for virulence factor membrane proteins, integral to the inner and outer membranes of M. tuberculosis and Y. pestis, the causative agents of tuberculosis and plague. The NMR structures characterized in lipids provide insights to their specific functions.