Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
Shandong Energy Institute, Qingdao 266101, China.
Sci Adv. 2023 Jul 21;9(29):eadg9141. doi: 10.1126/sciadv.adg9141.
Conformational dynamics is important for protein functions, many of which are performed in cells. How the intracellular environment may affect protein conformational dynamics is largely unknown. Here, loop conformational dynamics is studied for a model protein in cells by using nuclear magnetic resonance (NMR) spectroscopy. The weak interactions between the protein and surrounding macromolecules in cells hinder the protein rotational diffusion, which extends the dynamic detection timescale up to microseconds by the NMR spin relaxation method. The loop picosecond to microsecond dynamics is confirmed by nanoparticle-assisted spin relaxation and residual dipolar coupling methods. The loop interactions with the intracellular environment are perturbed through point mutation of the loop sequence. For the sequence of the protein that interacts stronger with surrounding macromolecules, the loop becomes more rigid in cells. In contrast, the mutational effect on the loop dynamics in vitro is small. This study provides direct evidence that the intracellular environment can modify protein loop conformational dynamics through weak interactions.
构象动力学对于蛋白质功能很重要，许多功能都是在细胞中执行的。细胞内环境如何影响蛋白质构象动力学在很大程度上是未知的。在这里，通过核磁共振（NMR）光谱法研究了模型蛋白在细胞中的环构象动力学。细胞中蛋白质与周围大分子之间的弱相互作用阻碍了蛋白质的旋转扩散，通过 NMR 自旋弛豫方法将动态检测时间尺度延长至微秒。通过纳米颗粒辅助自旋弛豫和残余偶极耦合方法证实了环的皮秒到微秒动力学。通过环序列的点突变干扰环与细胞内环境的相互作用。对于与周围大分子相互作用更强的蛋白质序列，环在细胞中变得更加刚性。相比之下，突变对环动力学的体外影响很小。这项研究提供了直接证据，表明细胞内环境可以通过弱相互作用来修饰蛋白质环构象动力学。
