Membrane-Dependent Conformation, Dynamics, and Lipid Interactions of the Fusion Peptide of the Paramyxovirus PIV5 from Solid-State NMR
Hongwei Yao, Mei Hong
Journal of Molecular Biology
The entry of enveloped viruses into cells requires protein-catalyzed fusion of the viral and cell membranes. The structure–function relation of a hydrophobic fusion peptide (FP) in viral fusion proteins is still poorly understood. We report magic-angle-spinning solid-state NMR results of the membrane-bound conformation, dynamics, and lipid interactions of the FP of the F protein of the paramyxovirus, parainfluenza virus 5 (PIV5). 13C chemical shifts indicate that the PIV5 FP structure depends on the composition of the phospholipid membrane: the peptide is α-helical in palmitoyloleoylphosphatidylglycerol-containing anionic membranes but mostly β-sheet in neutral phosphocholine membranes. Other environmental factors, including peptide concentration, cholesterol, membrane reconstitution protocol, and a Lys solubility tag, do not affect the secondary structure. The α-helical and β-sheet states exhibit distinct dynamics and lipid interactions. The β-sheet FP is immobilized, resides on the membrane surface, and causes significant membrane curvature. In contrast, the α-helical FP undergoes intermediate-timescale motion and maintains the lamellar order of the membrane. Two-dimensional 31P–1H correlation spectra show clear 31P–water cross peaks for anionic membranes containing the α-helical FP but weak or no 31P–water cross peak for neutral membranes containing the β-sheet FP. These results suggest that the β-sheet FP may be associated with high-curvature dehydrated fusion intermediates, while the α-helical state may be associated with the extended prehairpin state and the post-fusion state. Conformational plasticity is also a pronounced feature of the influenza and human immunodeficiency virus FPs, suggesting that these Gly-rich sequences encode structural plasticity to generate and sense different membrane morphologies.
Circular dichroism, Secondary structure, Vesicle interactions, Aggregation, Biochemistry