A possible role of histidine in a nickel resistant mechanism of Saccharomyces cerevisiae

When a nickel resistant strain N08 of S. cerevisiae was grown in a Ni-supplemented medium, approximately 70% of the nickel is distributed in the soluble fraction. The soluble fraction was chromatographed on Sephadex G-10 and the fraction contained both nickel and large amounts of histidine. When cells were grown in medium containing various combinations of nickel and magnesium and which exhibited approximately 50% growth inhibition, a molar ratio of intracellular histidine and nickel contents remained constant at 1.2-1.4, indicating that the increase in histidine content is correlated with nickel accumulation. The wild type strain 0605-S6, however, exhibits no increase in histidine content when grown in a Ni-supplemented medium, and, therefore, a nickel-resistant mechanism of yeast appears to be the formation of histidine-nickel complexes.