FIG. 4.

Effect of glycosylation on the resistance to proteases. Bacteria bearing an empty vector (−) or expressing unglycosylated AIDA-I (Aida) or glycosylated AIDA-I (Aida/Aah) were pelleted and resuspended in PBS in the presence or absence of trypsin or proteinase K (0.3 μg/ml⁻¹ and 3 μg/ml⁻¹). The amount of AIDA-I was revealed by immunoblotting with an anti-HisG antibody (upper panel), and the intensity of the bands was quantitated by densitometry and normalized (lower panel). MW, molecular weight.