Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing alpha or beta amino acid or substituted amino acid...
Patent
1995-10-27
1997-11-18
Wax, Robert A.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing alpha or beta amino acid or substituted amino acid...
435194, 43525232, 536 232, C12P 1308, C12N 912
Patent
active
056886713
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel aspartokinase and a DNA fragment coding for the enzyme originating from a bacterium belonging to the genus Corynebacterium used for fermentative production of amino acid and so on, and relates to recombinant DNA containing the DNA fragment. The present invention also relates to a bacterium belonging to the genus Corynebacterium harboring the recombinant DNA, and relates to a method of producing L-lysine comprising cultivating the microorganism.
BACKGROUND ART
L-Lysine, which is used as a feed additive, is usually produced by fermentation by using an L-lysine-producing mutant strain belonging to coryneform bacteria. A variety of L-lysine-producing bacteria are known at present, which are those created by artificial mutation of coryneform bacteria. Such artificial mutant strains includes the followings: S-(2-aminoethyl)cysteine (hereinafter abbreviated as "AEC") resistant mutant strains; mutant strains which require amino acid such as L-homoserine for their growth (Japanese Patent Publication Nos. 48-28078 and 56-6499); mutant strains which exhibit resistance to AEC and require amino acids such as L-leucine, L-homoserine, L-proline, L-serine, L-arginine, L-alanine, and L-valine (U.S. Pat. Nos. 3,708,395 and 3,825,472); L-lysine-producing mutant strains which exhibit resistance to DL-.alpha.-amino-.epsilon.-caprolactam, .alpha.-amino-lauryllactam, aspartic acid-analog, sulfa drug, quinoid, and N-lauroylleucine; L-lysine-producing mutant strains which exhibit resistance to inhibitors of oxyaloacetate decarboxylase or respiratory system enzymes (Japanese Patent Laid-open Nos. 50-53588, 50-31093, 52-102498, 53-9394, 53-86089, 55-9783, 55-9759, 56-32995 and 56-39778, and Japanese Patent Publication Nos. 53-43591 and 53-1833); L-lysine-producing mutant strains which require inositol or acetic acid (Japanese Patent Laid-open Nos. 55-9784 and 56-8692); L-lysine-producing mutant strains which exhibit sensitivity to fluoropyruvic acid or temperature not less than 34.degree. C. (Japanese Patent Laid-open Nos. 55-9783 and 53-86090); and mutant strains belonging to the genus Brevibacterium or Corynebacterium which exhibit resistance to ethylene glycol and produce L-lysine (U.S. patent application Ser. No. 333,455).
Escherichia coli transformed by using a recombinant vector is disclosed in the prior art. In this strain, amino acid production is enhanced (see U.S. Pat. No. 4,278,765).
In relation to the genera Brevibacterium and Corynebacterium, there are disclosed a vector plasmid which is autonomously replicable in bacterial cells and has a drug resistance marker gene (see U.S. patent application Ser. No. 386,980), and a method for introducing genes into bacterial cells (Japanese Patent Laid-open No. 2-207791). There is disclosed a possibility to breed L-threonine- or L-isoleucine-producing bacteria by using the techniques described above (see U.S. patent application Ser. Nos. 376,396 and 392,145). In relation to breeding of L-lysine-producing bacteria, a technique is known in which a gene relevant to L-lysine biosynthesis is integrated into a vector plasmid to amplify it in bacterial cells (for example, Japanese Patent Laid-open No. 56-160997). However, no prior art is known in which a gene is specified for aspartokinase (hereinafter referred to as "AK"), a mutation point on the AK gene is elucidated so that feedback inhibition by L-lysine and L-threonine is substantially desensitized, and it is elucidated that the mutation directly relates to productivity of L-lysine. Although a mutant AK gene is described in a few cases, the mutant AK gene could not be harbored as a stable plasmid (see Cremer, J. et al.; Applied and Environmental Microbiology, June 1991, pp. 1746-1752).
An object of the present invention is to make improvement to provide increased production and secretion speeds of L-lysine by modifying AK as an important enzyme for lysine biosynthesis in microorganisms of bacteria belonging to the genus Corynebacterium into those having a property of desens
REFERENCES:
Schrumpf et al (1992) Appl Microbiol Biotech 37:566-571 "Isolation and Prominent Characteristics of an L-lysine Hyperproducing Strain . . . ".
Kalinowski et al (1991) Molec. Micro. 5:1197-1204.
Mitsubishi Petrochemical Co, Ltd., Sequence Database Entry Based on JO6261766-A (Published Sep. 20, 1994).
Matsui Hiroshi
Ogawa Yuri
Sugimoto Masakazu
Suzuki Tomoko
Tanaka Akiko
Ajinomoto Co. Inc.
Mytelka Daniel
Wax Robert A.
LandOfFree
Mutant aspartokinase gene does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mutant aspartokinase gene, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mutant aspartokinase gene will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1564760