Patent ID: 7611873
Filing Date: 2009-11-03
Classification: C12N,C12P

Abstract:
1. A method for producing L-methionine which comprises culturing a recombinant Escherichia bacterium in a medium to produce and accumulate L-methionine in the medium in an amount in excess of the corresponding unmodified Escherichia bacterium, and collecting the L-methionine from the medium, wherein the bacterium is deficient in repressor of L-methionine biosynthesis system encoded by the endogenous metJ gene and has L-methionine productivity, activity of intracellular homoserine transsuccinylase encoded by the metA gene of a the bacterium comprises at least one characteristic selected from the group consisting of: (a) exhibits reduced activity of intracellular S-adenosylmethionine synthetase encoded by the endogenous metK gene as compared to an unmodified (b) exhibits L-threonine auxotrophy; (c) exhibits enhanced activity of intracellular cystathionine γ-synthase encoded by the metB gene of a (d) has a homoserine transsucinylase for which concerted inhibition by L-methionine and S-adenosylmethionine is desensitized, wherein the homoserine transsuccinylase comprising the amino acid sequence of SEQ ID NO: 26 contains at least one amino acid replacement wherein said at least one amino acid replacement is independently selected from the group consisting of replacement of the amino acid residue Arg-27 with cysteine, replacement of the amino acid residue Ile-296 with serine, and replacement of the amino acid residue Pro-298 with leucine.