The transmembrane domain of the SNARE protein VAMP2 is highly sensitive to its lipid environment.

Abstract Neurotransmitter and hormone exocytosis depends on SNARE protein transmembrane domains and membrane lipids but their interplay is poorly understood. We investigated the interaction of the structure of VAMP2, a vesicular transmembrane SNARE protein, and membrane lipid composition by infrared spectroscopy using either the wild-type transmembrane domain (TMD), VAMP2 TM22 , or a peptide mutated at the central residues G 100 /C 103 (VAMP2 TM22 VV) previously identified by us as being critical for exocytosis. Our data show that the structure of VAMP2 TM22 , in terms of α-helices and β-sheets is strongly influenced by peptide/lipid ratios, by lipid species including cholesterol and by membrane surface charges. Differences observed in acyl chain alignments further underscore the role of the two central small amino acid residues G 100 /C 103 within the transmembrane domain during lipid rearrangements in membrane fusion.