Mutant Phosphoribosylpyrophosphate Synthetase and Method for Producing L-Histidine
AssigneeAjinomoto Co., Inc.
InventorsElena Vitalievna Klyachko, Rustem Saidovich Shakulov, Yuri Ivanovich Kozlov
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Abstract
The present invention relates to a mutant bacterial PRPP synthetase which is resistant to feedback by purine nucleotides, and a method for producing L-histidine using the bacterium of the Enterobacteriaceae family wherein the L-amino acid productivity of said bacterium is enhanced by use of the PRPP synthetase which is resistant to feedback by purine nucleotides, coded by the mutant prsA gene.
Claims8
A method for producing L-histidine comprising cultivating a bacterium of the Enterobacteriaceae family in a culture medium, allowing said L-histidine to accumulate in the culture medium, and collecting said L-histidine from the culture medium, wherein said bacterium contains a DNA encoding a mutant phosphoribosylpyrophosphate synthetase (PRPP synthetase) comprising
- a) the amino acid sequence of a wild-type bacterial phosphoribosylpyrophosphate synthetase, except the aspartic acid at position 115 relative to wild-type E. coli phosphoribosylpyrophosphate synthetase is substituted with another L-amino acid, or
- b) an amino acid sequence wherein the aspartic acid at position 115 relative to E. coli phosphoribosylpyrophosphate synthetase is substituted with another L-amino acid, and one or more amino acids other than aspartic acid at position 115 are deleted, substituted, inserted, or added, wherein said amino acid sequence is at least 95% homologous with respect to the entire amino acid sequence of the wild-type PRPP synthetase from Escherichia coli,
- wherein said phosphoribosylpyrophosphate synthetase activity is maintained, and feedback inhibition by purine nucleotides is desensitized.
Dependencies are inferred from the claim text.