FIG. 1.

(A) The positions of insertion mutations in prgB are shown on a linear map of the gene. Each mutation consists of an in-frame 31-amino-acid insertion. The insertions at r2760 and r3183 are in frame but in the reverse orientation, while the insertion at s3599 is out of frame and produces a stop codon. Structural map: SS, signal sequence; helix, predicted N-terminal helix domain; variable, unconserved AS region; essential, aggregation domain identified by Muscholl-Silberhorn; and cleavage, site of cleavage that produces the characteristic N-terminal 78-kDa fragment. (B) The mutant Asc10 proteins were expressed using the nisin-inducible Asc10 expression vector pMSP7517.