Physical Chemistry Seminar: Professor Carlos Baiz, University of Texas at Austin (Host: Mike Fayer)
About the Seminar
"Characterizing molecular environments in lipid membranes using ultrafast infrared spectroscopy"
Lipid membranes are much more than barriers between cell compartments, they are integral components of the cell involved in key functions such as signaling, transport, and sensing. Membranes are composed of hundreds of different lipid species and contain thousands of proteins. The biological reason for this heterogeneity is not understood. We use ultrafast 2D IR spectroscopy to probe the local hydrogen-bond dynamics at the interface. Specifically, we investigate how cations, at physiological concentrations, alter the lipid-lipid and lipid-water interactions at the interface. Our results indicate that Ca2+ at low mM concentrations slows down the interfacial water dynamics. In the second part of this talk, I will discuss our current work on utilizing peptides with backbone isotope labels to probe the degree of water penetration into the bilayer, as well as using peptides to “crowd” the lipids. Our results show that the presence of polar residues in membrane proteins increase the degree of water penetration within the bilayer.
About the Speaker
Carlos Baiz is a faculty member at the University of Texas at Austin. His lab studies the biophysics of complex systems such as heterogeneous lipid membranes and membrane proteins using ultrafast two-dimensional infrared spectroscopy and molecular dynamics simulations. His group also develops vibrational models, including frequency maps to connect experiments with simulations. He has a Ph.D. in Chemistry from the University of Michigan where he worked in the lab of Prof. Kevin Kubarych and postdoctoral training at MIT and University of Chicago with Prof. Andrei Tokmakoff.