CBMS Lecture Series

Abstract: In the Vander Zanden lab, we use complementary liquid surface X-ray scattering and molecular dynamics methods to study the structure of protein/membrane interactions, particularly focusing on protein families that have dynamic behavior at membrane surfaces. Specifically, X-ray reflectivity and grazing incidence diffraction will be showcased as powerful tools for determining structural information about peripheral membrane proteins. We will discuss application of these techniques to study three protein/membrane systems: glycolipid recognition proteins, amyloidogenic proteins, and lipoxygenase enzymes. For each of these systems, a lipid monolayer is deposited at the air/water interface in a Langmuir trough, and proteins are injected into the liquid subphase below, where they can bind the membrane. These thin-film measurements are used to deduce an electron density profile describing the membrane and bound proteins. Diffraction data are used to detect semi-ordered species present at the membrane, such as protein assemblies and lipids organized into condensed domains. Overall, we feel these methods are a valuable addition to the classic suite of structural biology techniques, and their strength is the ability to capture a population of membrane proteins exhibiting dynamic behavior.