Figure 2.

Peptide binding to PDI mutants Δ252–277 and Δ222–302 is reduced, compared with wild-type. ¹²⁵I-labeled glycosylation acceptor peptide, N-benzoyl-NYT-amide, was translocated into PDI wild-type or mutant microsomes as described in Materials and Methods and cross-linked with longwave UV light. All samples were analyzed in duplicate. Proteins were resolved on 7.5% SDS gels and peptide–cross-linking products were visualized by autoradiography. Peptide binding to PDI was quantitated using a PhosphorImager (BioRad).