L-proline accumulation and freeze tolerance of Saccharomyces cerevisiae are caused by a mutation in the PRO1 gene encoding gamma-glutamyl kinase.

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Morita Y, Nakamori S, Takagi H

L-proline accumulation and freeze tolerance of Saccharomyces cerevisiae are caused by a mutation in the PRO1 gene encoding gamma-glutamyl kinase.

Appl Environ Microbiol. 2003 Jan;69(1):212-9.

PubMed ID

12513997 [ View in PubMed

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Abstract

We previously isolated a mutant which showed a high tolerance to freezing that correlated with higher levels of intracellular L-proline derived from L-proline analogue-resistant mutants. The mutation responsible for the analogue resistance and L-proline accumulation was a single nuclear dominant mutation. By introducing the mutant-derived genomic library into a non-L-proline-utilizing strain, the mutant was found to carry an allele of the wild-type PRO1 gene encoding gamma-glutamyl kinase, which resulted in a single amino acid replacement; Asp (GAC) at position 154 was replaced by Asn (AAC). Interestingly, the allele of PRO1 was shown to enhance the activities of gamma-glutamyl kinase and gamma-glutamyl phosphate reductase, both of which catalyze the first two steps of L-proline synthesis from L-glutamate and which together may form a complex in vivo. When cultured in liquid minimal medium, yeast cells expressing the mutated gamma-glutamyl kinase were found to accumulate intracellular L-proline and showed a prominent increase in cell viability after freezing at -20 degrees C compared to the viability of cells harboring the wild-type PRO1 gene. These results suggest that the altered gamma-glutamyl kinase results in stabilization of the complex or has an indirect effect on gamma-glutamyl phosphate reductase activity, which leads to an increase in L-proline production in Saccharomyces cerevisiae. The approach described in this paper could be a practical method for breeding novel freeze-tolerant yeast strains.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Glutamic acid	Delta-1-pyrroline-5-carboxylate synthase	Protein	Humans	Unknown	Not Available	Details