SARS-CoV-2 Fusion Peptide has a Greater Membrane Perturbating Effect than SARS-CoV with Highly Specific Dependence on Ca2+

•SARS-2 FP is more hydrophobic than SARS-1 FP.•SARS-2 FP induces greater membrane ordering than SARS-1 FP.•SARS-CoV-2 FP induces membrane ordering in a specific Ca2+-dependent fashion.•SARS-2 FP binds two Ca2+ and the binding sites are positively cooperative.•SARS-1 PP is even more effective in inducing membrane ordering than separate FPs.