Membrane structure and fusion-triggering conformational change of the fusion domain from influenza hemagglutinin.

摘要: The N-terminal domain of the influenza hemagglutinin (HA) is only portion molecule that inserts deeply into membranes infected cells to mediate viral and host cell membrane fusion. This constitutes an autonomous folding unit in membrane, causes hemolysis red blood catalyzes lipid exchange between juxtaposed a pH-dependent manner. Combining NMR structures determined at pHs 7.4 5 with EPR distance constraints, we have deduced HA bilayer. At both pHs, kinked, predominantly helical amphipathic structure. fusogenic pH 5, however, has sharper bend, additional 3(10)-helix twist, resulting repositioning Glu 15 Asp 19 relative nonfusogenic 7.4. Rotation these charged residues out plane creates hydrophobic pocket allows deeper insertion fusion core Such mode could perturb packing facilitate mixing membranes.