The SARS-CoV Fusion Peptide forms an Extended Bipartite Fusion Platform that Perturbs Membrane Order in a Calcium-Dependent Manner

In this study, we used this effect as a criterion to identify and characterize the bona fide SARS-CoV FP. Our results indicate that both FP1 and the region immediately downstream (amino acids 816–835 KQYGECLGDINARDLICAQKF, FP2) induce significant membrane ordering. Furthermore, their effects are calcium-dependent, which is consistent with in vivo data showing that calcium is required for SARS-CoV S-mediated fusion. Isothermal titration calorimetry showed a direct interaction between calcium cations and both FPs. This Ca2+-dependency membrane ordering was not observed with influenza FP, indicating that the coronavirus FP exhibits a mechanistically different behavior. Membrane ordering effects are greater and penetrate deeper into membranes when FP1 and FP2 act in a concerted manner, suggesting that they form an extended fusion “platform”. Graphical abstract
Source: Journal of Molecular Biology - Category: Molecular Biology Source Type: research