Gene dosage effect of L-proline biosynthetic enzymes on L-proline accumulation and freeze tolerance in Saccharomyces cerevisiae.

ABSTRACT: We have previously reported that L-proline has cryoprotective activity in Saccharomyces cerevisiae. A freeze-tolerant mutant with L-proline accumulation was recently shown to carry an allele of the PRO1 gene encoding gamma-glutamyl kinase, which resulted in a single amino acid substitution (Asp154Asn). Interestingly, this mutation enhanced the activities of gamma-glutamyl kinase and gamma-glutamyl phosphate reductase, both of which catalyze the first two steps of L-proline synthesis and which together may form a complex in vivo. Here, we found that the Asp154Asn mutant gamma-glutamyl kinase was more thermostable than the wild-type enzyme, which suggests that this mutation elevated the apparent activities of two enzymes through a stabilization of the complex. We next examined the gene dosag

SUBMITTER: Terao Y 

PROVIDER: S-EPMC262311 | biostudies-literature | 2003 Nov

REPOSITORIES: biostudies-literature