Mutations and genetic targets for enhanced l-tyrosine production
AssigneeMassachusetts Institute of Technology
InventorsChristine Santos, Gregory Stephanopoulos
Life of this patent
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Abstract
The invention relates to identification of mutations and genetic targets for enhanced L-tyrosine production, and bacterial strains capable of L-tyrosine production.
Claims33
A bacterial cell having improved L-tyrosine production relative to a parental strain, wherein the bacterial cell comprises
- (a) (1) one or more mutations in a sigma factor gene or a gene encoding an alpha subunit of RNA polymerase, and/or
- (2) increased expression, relative to a parental strain, of one or more of evgA, relA, gadA, gadB, gadC, gadE, hdeA, hdeB, hdeD, and/or slp;
- and
- (b) one or more mutations in hisH and/or purF.
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A method for producing L-tyrosine, the method comprising genetically modifying a bacterial cell to recombinantly express:
- (a) (1) one or more mutations in a sigma factor gene or a gene encoding an alpha subunit of RNA polymerase, and/or
- (2) increased expression, relative to a parental strain, of one or more of evgA, relA, gadA, gadB, gadC, gadE, hdeA, hdeB, hdeD, and/or slp;
- and
- (b) one or more mutations in hisH and/or purF,
- culturing a population of said cells, and
- optionally collecting L-tyrosine from the culture medium or the population of cells.
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An isolated nucleic acid molecule encoding a rpoA gene product comprising one or more mutations of the nucleotide sequence of E. coli K12 rpoA encoding a mutation of valine at amino acid residue 257 (V257) to arginine (V257R), or equivalent amino acid in other rpoA genes of E. coli or of other bacterial strains.
An isolated nucleic acid molecule encoding a rpoD gene product comprising truncation of the nucleotide sequence of E. coli K12 rpoD that results in a nucleotide sequence that encodes Region 4 and the end of Region 3 of RpoD protein, or equivalent region of RpoD in other rpoD genes of E. coli or of other bacterial strains.
An isolated nucleic acid molecule encoding a hisH gene product comprising one or more mutations of the nucleotide sequence of E. coli K12 hisH encoding a mutation of leucine at amino acid residue 82 (L82), or equivalent amino acid in other hisH genes of E. coli or of other bacterial strains.
An isolated nucleic acid molecule encoding a purF gene product comprising one or more mutations of the nucleotide sequence of E. coli K12 purF encoding a mutation of valine at amino acid at residue 5 (V5), or equivalent amino acid in other purF genes of E. coli or of other bacterial strains.
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Dependencies are inferred from the claim text.