Site-Directed EPR-Studies on the Effect of Bilayer Cholesterol Content on M2 Conformational Equilibrium

Abstract

Listen

Translate article

M2 is a homotetrameric membrane protein of influenza A that plays multiple roles in viral replication. Structural studies have shown that M2 conformation is dependent on the hydrophobic environment. In vivo influenza A membranes contain up to 40% cholesterol. Using side directed spin-labeling EPR, we studied the effect of bilayer cholesterol content on the conformation of a 38-residue M2 peptide spanning the transmembrane region and its C-terminal extension. CW and pulsed EPR spectra show evidence that M2 adopts multiple conformational states in bilayers, and that cholesterol content dictates the relative populations of the states.