Figure 5

A single arginine at the S2′ site is sufficient for MERS-S activation. (a) Equal volumes of culture supernatants containing pseudoparticles harboring MERS-S wt or the indicated S protein mutants equipped with a C-terminal V5-tag were centrifuged and the pellets subjected to Western blot analysis, using an anti-V5 antibody. The results were confirmed in four separate experiments. (b) Vero E6 and Caco-2 cells were transduced with pseudoparticles harboring MERS-S wt, the indicated S protein mutants, VSV-G or no glycoprotein at all (negative control), and transduction efficiency was analyzed as described in the legend to Fig. 4. The average of nine separate experiments is shown, in which transduction mediated by MERS-S wt was set as 100%. Error bars indicate SEM. Statistical significance of differences between transduction mediated by wt and mutant S proteins was analyzed using a paired, two-tailed students t-test (*p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ns, not significant).