IR Spectroscopy of Protein and Peptide-Membrane Interactions: In Situ Strategies for Tracking Fusion, Remodelling, and Refolding

Abstract

Attenuated total reflection-infrared spectroscopy is a powerful technique for characterizing protein and peptide-membrane interactions. Using a real-time, flow-through design and a single bounce diamond ATR element, we have examined how three different families of proteins interact with model supported lipid bilayers. These include (1) a lipid-remodelling protein from the saposin family; (2) the dynamin-related GTP-ase Mgm1p; (3) a series of model membranolytic peptides designed to adopt a helical motif in bacterial membranes. Our studies provided compelling evidence of the action of these proteins, including membrane remodeling, GTP-ase activity, and peptide aggregation. We will describe the integration of laser-based fluorescence spectroscopy with ATR-IR, which, when coupled with correlated in situ atomic force microscopy, will afford a uniquely capable multimodal imaging and characterization platform.