Disease relevance of PRO1

• We constructed plasmids carrying the Escherichia coli proB gene that encodes gamma-glutamyl kinase, under the control of the yeast GAL1 promoter [1].

High impact information on PRO1

• We constructed a novel sake yeast strain by disrupting the PUT1 gene, which is required for L-proline utilization, and replacing the wild-type PRO1 allele with the pro1(D154N) allele [2].
• This mutation increases the activity of gamma-glutamyl kinase and gamma-glutamyl phosphate reductase, which catalyze the first two steps of L-proline synthesis and which together may form a complex in vivo [2].
• 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) [3].
• 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 [4].
• 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) [4].

Biological context of PRO1

• Four close matches to the consensus sequence for GCN4 protein binding and one close match to the RAP1 protein-binding site were found in the PRO1 upstream region [5].
• 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 [3].
• Yeast pro1 mutants harboring these plasmids are proline prototrophs [1].

Associations of PRO1 with chemical compounds

• PRO1 expression was not repressed by exogenous proline and was not induced by the presence of glutamate in the growth medium [5].
• Strong homology is also found at the N-terminus to bacterial and yeast gamma-glutamyl kinase and at the C-terminus to bacterial gamma-glutamyl phosphate reductase [6].
• Mutants defective in the pro1 and pro2 genes can be satisfied by arginine or ornithine as well as proline [7].
• 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 [3].

Other interactions of PRO1

• In addition, a pro1 bradytrophic strain became completely auxotrophic for proline in a gcn4 strain background [5].

References