Kataoka M, Hashimoto K-I, Yoshida M, Nakamatsu T, Horinouchi S, Kawasaki H
Department of Biotechnology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
Lett Appl Microbiol. 2006 May;42(5):471-6. doi: 10.1111/j.1472-765X.2006.01905.x.
The ultimate aim is to elucidate the molecular mechanisms for glutamate overproduction by Corynebacterium glutamicum.
Gene expression in response to the conditions inducing glutamate overproduction was investigated by using a DNA microarray technique. Most genes involved in the EMP pathway, the PPP, and the TCA cycle were downregulated, while five genes that were highly upregulated (NCgl0917, NCgl2944, NCgl2945, NCgl2946, and NCgl2975) were identified under all the three conditions for overproduction that are studied here. Gene products of NCgl2944, NCgl2945, and NCgl2946 were highly homologous to each other, did not resemble any other protein, and have remained uncharacterized thus far. The product of NCgl0917 showed a similarity to a few hypothetical and uncharacterized proteins. NCgl2975 was homologous to metal-binding proteins.
The decrease in the activity of 2-oxoglutarate dehydrogenase complex, a key enzyme that is downregulated during glutamate overproduction, can be mainly attributed to the downregulation of odhA and sucB. Five highly upregulated genes were also identified.
Although fermentative production of glutamate has been carried out for more than 45 years, information on the molecular mechanisms of glutamate overproduction is still limited. This study further elucidates these mechanisms.
最终目的是阐明谷氨酸棒杆菌过量生产谷氨酸的分子机制。
采用DNA微阵列技术研究了响应诱导谷氨酸过量生产条件下的基因表达。参与糖酵解途径（EMP途径）、磷酸戊糖途径（PPP）和三羧酸循环（TCA循环）的大多数基因表达下调，而在本文研究的所有三种过量生产条件下，鉴定出五个高度上调的基因（NCgl0917、NCgl2944、NCgl2945、NCgl2946和NCgl2975）。NCgl2944、NCgl2945和NCgl2946的基因产物彼此高度同源，与任何其他蛋白质均不相似，迄今为止仍未得到表征。NCgl0917的产物与一些假定的未表征蛋白质具有相似性。NCgl2975与金属结合蛋白同源。
谷氨酸过量生产过程中关键酶2-氧代戊二酸脱氢酶复合体活性的降低，主要归因于odhA和sucB的下调。还鉴定出五个高度上调的基因。
尽管谷氨酸的发酵生产已经进行了45年以上，但关于谷氨酸过量生产分子机制的信息仍然有限。本研究进一步阐明了这些机制。
