Sequence-dependent backbone dynamics of a viral fusogen transmembrane helix

Abstract

The transmembrane domains of membrane fusogenic proteins are known to contribute to lipid bilayer mixing as indicated by mutational studies and functional reconstitution of peptide mimics. Here we demonstrate that mutations of a GxxxG motif or of Ile residues that were previously shown to compromise the fusogenicity of the Vesicular Stomatitis virus G-protein transmembrane helix reduce its backbone dynamics as determined by deuterium/hydrogen-exchange kinetics. Thus the backbone dynamics of these helices may be linked to their fusogenicity which is consistent with the known over-representation of Gly and Ile in viral fusogen transmembrane helices. The transmembrane domains of membrane fusogenic proteins are known to contribute to lipid bilayer mixing. Our present results demonstrate that mutations of certain residues that were previously shown to compromise the fusogenicity of the Vesicular Stomatitis virus G-protein transmembrane helix reduce its backbone dynamics. Thus the data suggest a relationship between sequence backbone dynamics and fusogenicity of transmembrane segments of viral fusogenic proteins. Published by Wiley-Blackwell. © 2012 The Protein Society.