Mechanism of membrane perturbation by the HIV-1 gp41 membrane-proximal external region and its modulation by cholesterol

► MPER is a membrane-transferring domain implied in the fusogenic activity of HIV gp41. ► The molecular mechanism underlying its membrane activity remains to be elucidated. ► We have studied this mechanism by X-ray scattering techniques in peptide-lipid monolayers. ► Our results support the idea that the hydrophobic insertion of MPER domain generates curvature within the viral membrane.