FIG. 38.

Comparison of the structure of the wt mature SFV with that of the SFVmSQL mutant shows the effect of cleavage of the spike protein precursor (p62) on the spike structure. The spike coalesces from an open structure with separated E1E2 heterodimers to a closed structure containing a cavity at its center. The modular nature of the structure is reflected in the observation that the capsid, transmembrane regions, and spike skirts are unchanged by the cleavage. Adapted from reference 118 with the permission of the author and the publisher.