空间微重力对航天医学、材料学等领域发展起到极其重要的推动作用,然而在生物化工领域的研究尚处于起步阶段.微生物在微重力环境中培养时,其生长代谢和基因转录表达都与地球重力场中截然不同.前期研究表明表达重组β-葡萄糖醛酸苷酶的大肠杆菌在模拟微重力(simulated microgravity,SMG)环境中菌体生长和外源蛋白质表达量均比正常重力对照(normal gravity,NG)环境要高.为深入分析SMG环境效应对菌株在外源蛋白质表达过程中的影响,对该重组大肠杆菌菌株在SMG和NG培养过程中加入IPTG诱导外源蛋白质表达4 h后的全细胞蛋白质酶解产物,通过三重稳定同位素二甲基标记方法并结合质谱分离鉴定技术,在肽段水平上标记后进行差异定量蛋白质组学分析.结果表明:与NG对照相比,SMG条件下共有124个蛋白质表达水平发生显著变化,其中92个蛋白质上调,6个蛋白质下调.上调蛋白质集中在细胞压力胁迫、氨基酸代谢、翻译转录和碳代谢等途径,这些相关途径的蛋白质表达水平变化可以影响大肠杆菌生理代谢及外源蛋白质表达效率.%Microgravity effects were reported to affect the physiological characteristics and perturbations at the molecular levels of the microorganisms.Our previous works reported that the recombinantβ-glucuronidase (PGUS) expressing strainEscherichia coliBL21 (DE3)/pET28a-pgus grew faster and the efficiency of recombinant protein production was also enhanced under simulated microgravity (SMG) as compared with the normal gravity (NG). In this study, a quantitative proteomic analysis of triple stable isotope dimethyl labeling using mass spectrometry method to investigate the effects of SMG on the strain and the during recombinant protein production process was performed. A total of 124 differentially expressed proteins under SMG were identified as compared with NG. Among them, 92 proteins were significantly up-regulated and 6 proteins were drastically down-regulated under SMG. The majority of the up-regulated proteins were involved with the metabolism of cell stress response, amino acid metabolism, translation, transcription and carbohydrate metabolic process. The results indicated that the differentially expressed levels of these proteins under SMG were beneficial to the synthesis of the heterologous protein expression of the recombinantEscherichia coli.
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