The linear-plasmid-encoded toxin produced by the yeast Pichia acaciae: characterization and comparison with the toxin of Kluyveromyces lactis.

The toxin produced by Pichia acaciae was purified and its properties compared to those of the toxin from Kluyveromyces lactis. Like this toxin, the P. acaciae toxin is a protein comprised of three subunits (molecular masses 110, 39 and 38 kDa) with an associated chitinase activity and a pH optimum between 7.0 and 7.5. P. acaciae toxin also caused G1 cell cycle arrest. Of the thirteen recessive alleles that provided resistance in Saccharomyces cerevisiae to K. lactis toxin, only three also conferred resistance to P. acaciae toxin. Similarities and differences in the interactions of the two toxins with yeast cells are discussed.