Figure 1.

Schematic diagram illustrating differences in quaternary assembly between non-selective (left panels) and selective (right panels) strains. Non-selective strains can accommodate diglycosylated sialoglycoforms due to rotation between neighboring PrP molecules that allows spatial separation of glycans. In selective strains, the rotation between neighboring PrP molecules is very small (a) or absent (b). Recruitment of diglycosylated molecules by selective strains would lead to spatial interference between glycans (c). Negative selection of diglycosylated molecules helps to minimize spatial and electrostatic interference between glycans (d).