Yeast α factor is processed from a larger precursor polypeptide: The essential role of a membrane-bound dipeptidyl aminopeptidase

摘要: Abstract Alpha factor mating pheromone is a peptide of 13 amino acids secreted by Saccharomyces cerevisiae α cells. Nonmating ("sterile," or ste ) α-cell mutants bearing defects in the STE13 gene do not produce normal factor, but release collection incompletely processed forms (α factor∗) that have markedly reduced specific biological activity. The major α-factor∗ peptides structures H 2 N-GluAlaGluAla-α and N-AspAlaGluAla-α factor. ste13 lack membrane-bound heat-stable dipeptidyl aminopeptidase (DPAPase A) specifically cleaves on carboxyl side repeating -X-Ala- sequences. Absence DPA-Pase A other phenotypes lesion cosegregate genetic crosses. cloned plasmid causes yeast cells to overproduce DPAPase severalfold. different DNA segment, which weakly suppresses defects, overproduction heat-labile activity B) about tenfold. Other experiments indicate action may be ratelimiting for α-factor maturation