谷氨酸棒杆菌PhoPR双组分系统应答低氧胁迫功能研究

Functional study of PhoPR two-component system in response to low oxygen stress in Corynebacterium glutamicum

探究谷氨酸棒杆菌(Corynebacterium glutamicum,C. glutamicum)中PhoPR双组分系统响应外界溶氧变化功能机制。通过转录组数据分析发现PhoPR为C. glutamicum在不同溶氧水平下转录变化最明显双组分系统(Two-component system,TCS),表明PhoPR可感应环境中氧气变化。实时荧光定量PCR(Real-time quantitative PCR,RT-qPCR)和电泳迁移率试验(Electrophoretic mobility shift assay,EMSA)表明PhoPR效应蛋白PhoP可直接调控电子传递链相关基因sdhCAB和细胞膜相关基因betP、proP,间接调控qcrB,PhoPR高表达可增强细胞电子传递链和细胞膜基因转录。另外PhoPR还影响胞内ATP生成速度和峰值。基于以上结果推断,PhoPR通过调节电子传递链和ATP生成以维持C. glutamicum在低氧条件下生命活动。

The mechanism of PhoPR two-component system(TCS) in response to the changes in dissolved oxygen was explored in Corynebacterium glutamicum(C. glutamicum). Transcriptome data analysis found that PhoPR was TCS with the most significant change of transcriptional levels under different dissolved oxygen conditions, indicating that PhoPR could sense changes of oxygen in the environment. Real-time quantitative PCR(RT-qPCR) and electrophoretic mobility shift assay(EMSA)showed that the response regulators(RR) protein PhoP in PhoPR could directly regulate the electron transfer chain related genes sdhCAB and cell membrane related genes betP and proP, and indirectly regulate qcrB. It was revealed that the overexpression of PhoPR could enhance the transcription of cel electron transfer chain and membrance genes. In addition, PhoPR affected the rate and peak of intracel ular ATP production. Based on the results, it was concluded that PhoPR regulates the electron transfer chain and ATP production to maintain the life activities of C. glutamicum under low oxygen condition.