| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new DNA fragment which has a specific restriction enzyme cleavage map, contains a gene having a specific base pair number coding for 2-aminothiazolin-4-carboxylic acid racemase, and is useful for producing L-cysteine, L-cysteine synthase, and so on. SOLUTION: A new DNA fragment is provided which has the restriction enzyme cleavage map represented by the formula, contains a gene having 4.8 kbp coding for 2-aminothiazolin-4-carboxylic acid(ATC) racemase, and is useful for producing L-cysteine by affecting DL-ATC, ATC racemase which forms L-cysteine, and so on. This DNA fragment is obtained by treating Pseudomonas ovalis strain BS (FERM P-16965) with nitrosoguanidine to induce mutagenesis, selecting a strain which can not grow when using D-ATC as a sole nitrogen source among the obtained mutants, introducing a DNA fragment from the parent strain into the obtained strain, followed by recovering the DNA fragment which was introduced into a strain which was transformed so as to be able to grow when using D-ATC as a sole nitrogen source. |
