Genetic Redundancy and the Adaptation to Facultative Metabolism in Yeast: The Existence of Two NADP-Glutamate Dehydrogenase is Compelling for Growth under Fermentative and Respiratory Conditions

DELUNA, A.; RIEGO, L.; AVENDAÑO, A.; GONZÁLEZ, A.

CIFN XX Anniversary

UNAM

Lugar: Cuernavaca, Morelos; Año: 2001; p. 134 - 137

The genome of Saccharomyces cerevisiae contains several duplicated regions. This redundancy phenomenon is probably the result of a single whole-genome duplication, as well as the occurrence of sporadic independent shortsegment repeats. It has been proposed that the gross duplication might coincide with the origin of the ability to grow under anaerobic conditions. In this paper we review the analysis of the duplicated NADP· glutariiate dehydrogenase pathway, which has shown that GDHI and GDH3 play non-redundant roles under fermentative and respiratory conditions. These isoenzymes are specialized at the genetical and biochemical levels in a way such that glutamate biosynthesis is achieved without impairing the energy-providing pathways; the system modulates a-ketoglutarate utilization. Duplication and further diversification of a biosynthetic glutamate dehydrogenase may be representative of a general mechanism through which this yeast acquired facultative metabolic properties.