Mutational Analysis of the Functional Domains of Yeast K1 Killer Toxin

Abstract

To determine the functional domains of K1 killer toxin, we analyzed the phenotypes of a set of mutations throughout regions encoding the α- and β-toxin subunits that allow secretion of mutant toxins. A range of techniques have been used to examine the ability of mutant toxins to bind to β-glucan cell wall receptor and to form lethal ion channels. Our results indicate that both the α and β subunits are involved in β-glucan receptor binding. Defects in ion channel formation and toxin immunity are confined to the hydrophobic a subunit of the toxin.