Laboratoire Réactions et Génie des Procédés, UPR CNRS 3349, Institut National Polytechnique de Lorraine, Nancy Université, 2, Avenue de Forêt de Haye, BP 172, 54505 Vandoeuvre-lès-Nancy, France.
Appl Microbiol Biotechnol. 2010 Aug;87(5):1867-74. doi: 10.1007/s00253-010-2599-y. Epub 2010 May 7.
In Corynebacterium glutamicum, the activity of the 2-oxoglutarate dehydrogenase complex was shown to be controlled by the phosphorylation of a 15-kDa protein OdhI by different serine/threonine protein kinases. In this paper, the phosphorylation status and kinetics of OdhI dephosphorylation were assessed during glutamate producing processes triggered by either a biotin limitation or a temperature upshock from 33 degrees C to 39 degrees C. A dephosphorylation of OdhI in C. glutamicum 2262 was observed during the biotin-limited as well as the temperature-induced glutamate-producing process. Deletion of pknG in C. glutamicum 2262 did not affect the phosphorylation status of OdhI during growth and glutamate production phases triggered by a temperature upshock, though a 40% increase in the specific glutamate production rate was measured. These results suggest that, under the conditions analyzed, PknG is not the kinase responsible for the phosphorylation of OdhI in C. glutamicum 2262. The phosphorylation status of OdhI alone is, as expected, not the only parameter that determines the performance of a specific strain, as no clear relation between the specific glutamate production rate and OdhI phosphorylation level was demonstrated.
在谷氨酸棒杆菌中，2- 酮戊二酸脱氢酶复合物的活性被证明受到不同丝氨酸/苏氨酸蛋白激酶磷酸化 15kDa 蛋白 OdhI 的控制。在本文中，在生物素限制或从 33°C 到 39°C 的温度冲击触发的谷氨酸生产过程中，评估了 OdhI 去磷酸化的磷酸化状态和动力学。在生物素限制和温度诱导的谷氨酸生产过程中，观察到谷氨酸棒杆菌 2262 中的 OdhI 去磷酸化。尽管测量到特定谷氨酸生产速率增加了 40%，但在温度冲击触发的生长和谷氨酸生产阶段，缺失 C. glutamicum 2262 中的 pknG 并不影响 OdhI 的磷酸化状态。这些结果表明，在所分析的条件下，PknG 不是负责 C. glutamicum 2262 中 OdhI 磷酸化的激酶。如预期的那样，OdhI 的磷酸化状态本身并不是决定特定菌株性能的唯一参数，因为没有证明特定谷氨酸生产速率和 OdhI 磷酸化水平之间存在明显的关系。
