Various mutations by using yeast gene for protein-engineering.

Abstract

For construct an efficient-ethanol fermentation system from xylose by using yeast, several protein-engineering of xylitol dehydrogenase (XDH) were carried out. At first, we created a NADP+-dependent XDH by multiple site-directed mutagenesis. Furthermore, we succeeded to improve the thermostability by introduction of the structural zinc atom into XDH which does not possess a second zinc atom natively. Finally, the introduction of a structural zinc atom into the NADP+-dependent XDH mutant increased the thermostability of this mutant and improved further the catalytic efficiency with NADP+.