Calcium‐dependent conformational changes of membrane‐bound Ebola fusion peptide drive vesicle fusion

Abstract
The fusogenic subdomain of the Ebola virus envelope glycoprotein is an internal sequence located ca. 20 residues downstream the N‐terminus of the glycoprotein transmembrane subunit. Partitioning of the Ebola fusion peptide into membranes containing phosphatidylinositol in the absence of Ca2+ stabilizes an α‐helical conformation, and gives rise to vesicle efflux but not vesicle fusion. In the presence of millimolar Ca2+ the membrane‐bound peptide adopts an extended β‐structure, and induces inter‐vesicle mixing of lipids. The peptide conformational polymorphism may be related to the flexibility of the virus–cell intermembrane fusogenic complex.