Hayashi Mikiro, Mizoguchi Hiroshi, Ohnishi Junko, Mitsuhashi Satoshi, Yonetani Yoshiyuki, Hashimoto Shin-ichi, Ikeda Masato
BioFrontier Laboratories, Kyowa Hakko Kogyo Co., Ltd., Machida, Tokyo 194-8533, Japan.
Appl Microbiol Biotechnol. 2006 Oct;72(4):783-9. doi: 10.1007/s00253-006-0539-7. Epub 2006 Aug 30.
We previously found by transcriptome analysis that global induction of amino acid biosynthetic genes occurs in a classically derived industrial L-lysine producer, Corynebacterium glutamicum B-6. Based on this stringent-like transcriptional profile in strain B-6, we analyzed the relevant mutations from among those identified in the genome of the strain, with special attention to the genes that are involved in amino acid biosynthesis and metabolism. Among these mutations, a Gly-456-->Asp mutation in the 3-isopropylmalate dehydratase large subunit gene (leuC) was defined as a useful mutation. Introduction of the leuC mutation into a defined L-lysine producer, AHD-2 (hom59 and lysC311), by allelic replacement led to the phenotype of a partial requirement for L-leucine and approximately 14% increased L-lysine production. Transcriptome analysis revealed that many amino acid biosynthetic genes, including lysC-asd operon, were significantly upregulated in the leuC mutant in a rel-independent manner.
我们之前通过转录组分析发现，在一株经典衍生的工业L-赖氨酸生产菌谷氨酸棒杆菌B-6中，氨基酸生物合成基因会发生全局诱导。基于菌株B-6中这种类似严谨反应的转录谱，我们从该菌株基因组中鉴定出的突变中分析了相关突变，特别关注参与氨基酸生物合成和代谢的基因。在这些突变中，3-异丙基苹果酸脱水酶大亚基基因（leuC）中的一个甘氨酸456突变为天冬氨酸的突变被确定为一个有用的突变。通过等位基因替换将leuC突变引入一株确定的L-赖氨酸生产菌AHD-2（hom59和lysC311）中，导致了对L-亮氨酸部分需求的表型以及L-赖氨酸产量增加约14%。转录组分析表明，许多氨基酸生物合成基因，包括lysC-asd操纵子，在leuC突变体中以不依赖rel的方式显著上调。
