CPC C12P 21/02 (2013.01) [C07K 5/0806 (2013.01); C07K 5/0819 (2013.01); C12N 1/205 (2021.05); C12N 9/93 (2013.01); C12N 15/09 (2013.01); C12R 2001/19 (2021.05); C12Y 603/02002 (2013.01); C12Y 603/02003 (2013.01)] | 14 Claims |
1. A modified, Escherichia coli bacterium,
wherein the bacterium has a deleted ybdK gene that encodes γ-glutamylglycine synthetase that is at least 90% identical to the amino acid sequence of SEQ ID NO: 16, wherein the bacterium has a reduced γ-glutamylglycine synthetase activity compared to a non-modified bacterium,
wherein the bacterium has a deleted gshA gene that encodes a γ-glutamylcysteine synthetase that is at least 90% identical to the amino acid sequence of SEQ ID NO: 24,
wherein the bacterium has a reduced γ-glutamylcysteine synthetase activity compared to a non-modified bacterium,
wherein the bacterium has a deleted gene that encodes a γ-glutamyltransferase that is at least 90% identical to the amino acid sequence of SEQ ID NO: 26, wherein the bacterium has a reduced γ-glutamyltransferase activity compared to a non-modified bacterium,
wherein the bacterium has a gene encoding γ-glutamylvaline synthetase, wherein the γ-glutamylvaline synthetase has an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO: 24 mutated with a substitution at a position selected from L135, Q144, Y241, N243, and Y300, or wherein the γ-glutamylvaline synthetase has an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO: 18, 20, or 22,
wherein the γ-glutamylvaline synthetase has a ratio of γ-glutamylvaline synthetase activity to γ-glutamylglycine synthetase activity of at least 3.0, and
wherein the bacterium has enhanced ability to produce γ-glutamylvaline or γ-glutamylvalylglycine compared to a non-modified bacterium.
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