Figure 3.
Expression of mutant α-factor precursors. Yeast strain ABY08 was transformed with pBM258 (control plasmid or “−”), YCpG-MFα1–100 (K), and with plasmids carrying P2-substituted mutant alleles of MFα1–100 indicated using the single letter amino acid code. The amber termination codon in place of Lys84 is labeled “amb.” Enzymatically deglycosylated proteins from culture media were separated by SDS/PAGE, blotted, and probed with anti-(pro-α-factor) antiserum as described in Materials and Methods. Mfα1–120p with Cys at P2 formed an intermolecular disulfide and was only partially digested (shown) with Endoglycosidase H unless reduced with β-mercaptoethanol before deglycosylation (data not shown).