Fig 2.

Photoprobe binds to CNBr fragment B of Ost1p. (a) Diagram of Ost1p structure with the position of Met residues that are expected to be cleaved by CNBr indicated by the arrow. A, B, and C indicate the three large CNBr cleavage products with their calculated backbone molecular masses. In addition, potential N-glycosylation sites (asterisks) and their amino acid positions are shown. (b) Microsomes were prepared from each strain carrying an N to Q mutation and from the wild-type strain, and photolabeling was performed. Immunoprecipitation was carried out with the photolyzed microsomes and the eluants from the precipitants were subjected to CNBr cleavage, resolved on SDS/PAGE, and detected by autoradiography.