Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands.
Department of Chemistry, UC Berkeley, Stanley Hall, Berkeley, CA 94720, USA.
Sci Adv. 2022 Aug 12;8(32):eabo5387. doi: 10.1126/sciadv.abo5387.
We analyze the structure of the cytoplasm by performing single-molecule displacement mapping on a diverse set of native cytoplasmic proteins in exponentially growing . We evaluate the method for application in small compartments and find that confining effects of the cell membrane affect the diffusion maps. Our analysis reveals that protein diffusion at the poles is consistently slower than in the center of the cell, i.e., to an extent greater than the confining effect of the cell membrane. We also show that the diffusion coefficient scales with the mass of the used probes, taking into account the oligomeric state of the proteins, while parameters such as native protein abundance or the number of protein-protein interactions do not correlate with the mobility of the proteins. We argue that our data paint the prokaryotic cytoplasm as a compartment with subdomains in which the diffusion of macromolecules changes with the perceived viscosity.
我们通过在指数生长期的多种天然细胞质蛋白上进行单分子位移映射来分析细胞质的结构。我们评估了该方法在小隔间中的应用，并发现细胞膜的约束效应会影响扩散图谱。我们的分析表明，蛋白质在两极的扩散速度始终比在细胞中心慢，即超过细胞膜的约束效应。我们还表明，扩散系数与所使用探针的质量成比例，同时考虑蛋白质的寡聚状态，而诸如天然蛋白质丰度或蛋白质-蛋白质相互作用的数量等参数与蛋白质的迁移率不相关。我们认为，我们的数据将原核细胞质描绘为具有亚域的隔室，其中大分子的扩散随感知的粘度而变化。
