Tran Buu Minh, Prabha Haritha, Iyer Aditya, O'Byrne Conor, Abee Tjakko, Poolman Bert
Department of Biochemistry, University of Groningen, Groningen, Netherlands.
School of Natural Sciences, National University of Ireland, Galway, Ireland.
Front Microbiol. 2021 Feb 17;12:640149. doi: 10.3389/fmicb.2021.640149. eCollection 2021.
Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient ( ) of GFP in as a function of osmotic stress, temperature, and media composition. We find that is much less affected by hyperosmotic stress in than under similar conditions in and . We find a temperature optimum for protein diffusion in at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of is comparable to other Gram-positive bacteria like and but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how survives during environmental transmission and interaction with the human host.
蛋白质在细胞质中的流动性对细胞功能至关重要，而缓慢扩散可能会限制活细胞中生化反应的速率。在这里，我们测定了绿色荧光蛋白（GFP）在[具体对象]中的表观横向扩散系数（[具体符号]），它是渗透应激、温度和培养基成分的函数。我们发现，与在[其他对象1]和[其他对象2]的类似条件下相比，[具体对象]中的[具体符号]受高渗应激的影响要小得多。我们发现[具体对象]中蛋白质扩散的最适温度为30°C，这与稀溶液条件下广义斯托克斯 - 爱因斯坦方程预测的趋势不同，表明细胞质的结构和大分子拥挤程度随温度变化。[具体对象]的膨压与[其他革兰氏阳性菌1]和[其他革兰氏阳性菌2]等其他革兰氏阳性菌相当，但在缺乏应激诱导型西格玛因子SigB的基因敲除菌株中更高。我们在[具体对象]在环境传播以及与人类宿主相互作用过程中如何存活的背景下讨论了这些发现。
