| Comments |
P.6 left column bottom paragraph: "Table 2 summarizes the variation of capsid volume inside families, with respect to capsid dimensions. It relies on atomic structural data in VIPERdb. In order to quantify variation [investigators] used the coefficient of variation (CV) statistical measure calculated individually for each family with respect to its genera. Table 2 summarizes 40 genera in 13 families. Only families for which sufficient structural data was available are included (at least two genera per family). The results of this analysis demonstrate that a physical variation exists inside icosahedral families (16 % and 20 % on average for inner and outer volumes, respectively). In many instances the differences between the inner and outer volumes are substantial. For these instances, the default estimate of virus size [ref 47] that is often used is misleading." P.9 right column bottom paragraph: "Are icosahedral capsids unable to continuously change along evolution? Although changing the T [icosahedric triangulation] number would result a major change in the capsid size, it might indeed be possible to slightly change the size of each subunit composing the capsid. Indeed, a variance in both the inner and outer capsid volumes exists among the genera of icosahedral families (Table 2). [Investigators’] structural results undermine the common claim that the alleged compression requirement of viruses is driven by physical size constraints imposed by a limited space in their capsid." |