Glycosylation is suggested to have a role in prion strain maintenance and the species barrier [42] by modulating the fidelity of interaction, which may explain the favorable binding of un-glycosylated PrP by MBP-PrP (which is also un-glycosylated, indicating that binding preferably occurs between compatible glycosylated molecules) in the scrapie negative homogenate. Here, PRNP is linked to scrapie.