Perturbations in the native structure, often caused by stressing cellular conditions, not only impair protein function but also lead to the formation of aggregates, which can accumulate in the cell leading to harmful effects. Some organisms, such as plants, express the molecular chaperone HSP100 (homologous to HSP104 from yeast), which has the remarkable capacity to disaggregate and reactivate proteins. Recently, studies with animal cells, which lack a canonical HSP100, have identified the involvement of a distinct system composed of HSP70/HSP40 that needs the assistance of HSP110 to efficiently perform protein breakdown. As sessile plants experience stressful conditions more severe than those experienced by animals, we asked whether a plant HSP110 could also play a role in collaborating with HSP70/HSP40 in a system that increases the efficiency of disaggregation. Thus, the gene for a putative HSP110 from the cereal Sorghum bicolor was cloned and the protein, named SbHSP110, purified. For comparison purposes, human HsHSP110 (HSPH1/HSP105) was also purified and investigated in parallel. First, a combination of spectroscopic and hydrodynamic techniques was used for the characterization of the conformation and stability of recombinant SbHSP110, which was produced folded. Second, small-angle X-ray scattering and combined predictors of protein structure indicated that SbHSP110 and HsHSP110 have similar conformations. Then, the chaperone activities, which included protection against aggregation, refolding, and reactivation, were investigated, showing that SbHSP110 and HsHSP110 have similar functional activities. Altogether, the results add to the structure/function relationship study of HSP110s and support the hypothesis that plants have multiple strategies to act upon the reactivation of protein aggregates.

中文翻译：

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Sorghum bicolor SbHSP110 具有细长的形状，能够防止聚集并在重折叠和分解测定中替代人 HSPH1/HSP110

通常由压力细胞条件引起的天然结构扰动不仅会损害蛋白质功能，还会导致聚集体的形成，聚集体会在细胞中积聚，从而导致有害影响。一些生物体，例如植物，表达分子伴侣 HSP100（与酵母中的 HSP104 同源），它具有分解和重新激活蛋白质的卓越能力。最近，对缺乏典型 HSP100 的动物细胞的研究已经确定了由 HSP70/HSP40 组成的独特系统的参与，该系统需要 HSP110 的帮助才能有效地进行蛋白质分解。由于无柄植物经历的压力条件比动物经历的压力条件更严重，我们询问植物 HSP110 是否也可以在提高分解效率的系统中与 HSP70/HSP40 协作发挥作用。因此，来自谷物的推定 HSP110 的基因双色高粱克隆并纯化了名为 SbHSP110 的蛋白质。出于比较目的，人 HsHSP110 (HSPH1/HSP105) 也进行了纯化和平行研究。首先，结合使用光谱学和流体动力学技术来表征折叠生产的重组 SbHSP110 的构象和稳定性。其次，小角度 X 射线散射和蛋白质结构的组合预测因子表明 SbHSP110 和 HsHSP110 具有相似的构象。然后，研究了包括防止聚集、再折叠和再激活在内的伴侣活性，表明 SbHSP110 和 HsHSP110 具有相似的功能活性。共，