Zhu Haojie, Matsusaki Motonori, Sugawara Taiga, Ishimori Koichiro, Saio Tomohide
Institute of Advanced Medical Sciences, Tokushima University, Tokushima 770-8503, Japan.
Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Biology (Basel). 2021 Oct 26;10(11):1106. doi: 10.3390/biology10111106.
trigger factor (TF) is a zinc-dependent molecular chaperone whose folding-arrest activity is regulated by Zn. However, little is known about the mechanism of zinc-dependent regulation of the TF activity. Here we exploit in vitro biophysical experiments to investigate zinc-binding, the oligomeric state, the secondary structure, and the thermal stability of TF in the absence and presence of Zn. The data show that full-length TF binds Zn, but the isolated domains and tandem domains of TF do not bind to Zn. Furthermore, circular dichroism (CD) and nuclear magnetic resonance (NMR) spectra suggested that Zn-binding induces the partial structural changes of TF, and size exclusion chromatography-multi-angle light scattering (SEC-MALS) showed that Zn promotes TF oligomerization. Given the previous work showing that the activity regulation of trigger factor is accompanied by oligomerization, the data suggest that TF exploits zinc ions to induce the structural change coupled with the oligomerization to assemble the client-binding site, thereby effectively preventing proteins from misfolding in the thermal environment.
触发因子（TF）是一种锌依赖性分子伴侣，其折叠抑制活性受锌调节。然而，关于锌依赖性调节TF活性的机制知之甚少。在这里，我们利用体外生物物理实验来研究在有无锌的情况下TF的锌结合、寡聚状态、二级结构和热稳定性。数据表明，全长TF结合锌，但TF的分离结构域和串联结构域不与锌结合。此外，圆二色性（CD）和核磁共振（NMR）光谱表明，锌结合诱导了TF的部分结构变化，尺寸排阻色谱-多角度光散射（SEC-MALS）表明锌促进TF寡聚化。鉴于之前的工作表明触发因子的活性调节伴随着寡聚化，数据表明TF利用锌离子诱导与寡聚化相关的结构变化，以组装客户结合位点，从而有效地防止蛋白质在热环境中错误折叠。
