Role of the glutamic and aspartic residues in Na+-ATPase function in the ZrENA1 gene of Zygosaccharomyces rouxii.

The effect of replacement of negatively charged amino acid residues on the function of Na+ transport proteins of the salt-tolerant yeast Zygosaccharomyces rouxii was examined by heterologous expression of mutant proteins in a strain of Saccharomyces cerevisiae, RH16.6, that lacks native Na+-ATPase activity due to null mutations of ENA1, ENA2, ENA3, and ENA4. Mutants of Na+/H+ antiporter gene (ZrSOD2) and Na+-ATPase gene (ZrENA1) of Z.