| 摘要 |
A coryneform bacterium (I) in which the mdhA gene is attenuated, preferably eliminated, is new. Independent claims are also included for the following: (1) a polynucleotide (II) from coryneform bacteria, containing a polynucleotide sequence which codes for the mdhA gene, selected from: (a) a polynucleotide which is at least 70% identical to a polynucleotide which encodes a sequence (S1) of 328 amino acids fully defined in the specification; (b) a polynucleotide which encodes a polypeptide comprising a sequence which is at least 70% identical to S1; (c) complements of the above mentioned polynucleotide sequences; and (d) a polynucleotide comprising at least 15 successive nucleotides of the above mentioned polynucleotide sequences, where the polypeptide has the activity of malate dehydrogenase; (2) an isolated polypeptide (III) with malate dehydrogenase activity, which comprises the N-terminal amino acid sequence Asn-Ser-Pro-Gln-Asn-Val-Ser-Thr-Lys-Lys-Val-Thr-Val-Thr-Gly-Ala-Ala-G ly-Gln-Ile; (3) process (M1) for the preparation of L-amino acids in particular L-lysine comprising: (a) fermenting (I) which produces the desired L-amino acid and in which the mdhA gene is attenuated; (b) concentrating the desired product in the medium or in the cells of the bacteria; and (c) isolating the L-amino acid; (4) discovering (M2) RNA, DNA and cDNA in order to isolate nucleic acids, polynucleotides or genes which code for malate dehydrogenase or have high similarity to the sequence of the malate dehydrogenase gene comprising employing (II) as hybridization probes. |
