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Conformational stability and dynamics in crystals recapitulate protein behaviour in solution
Biophysical Journal ( IF 3.4 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.bpj.2020.07.015
Benedetta Maria Sala 1 , Tanguy Le Marchand 2 , Guido Pintacuda 2 , Carlo Camilloni 1 , Antonino Natalello 3 , Stefano Ricagno 1
Affiliation  

A growing body of evidences has established that in many cases proteins may preserve most of their function and flexibility in a crystalline environment, and several techniques are today capable to characterize molecular properties of proteins in tightly packed lattices. Intriguingly, in the case of amyloidogenic precursors, the presence of transiently populated states (hidden to conventional crystallographic studies) can be correlated to the pathological fate of the native fold; the low fold stability of the native state is a hallmark of aggregation propensity. It remains unclear, however, to which extent biophysical properties of proteins such as the presence of transient conformations or protein stability characterized in crystallo reflect the protein behavior that is more commonly studied in solution. Here, we address this question by investigating some biophysical properties of a prototypical amyloidogenic system, β2-microglobulin in solution and in microcrystalline state. By combining NMR chemical shifts with molecular dynamics simulations, we confirmed that conformational dynamics of β2-microglobulin native state in the crystal lattice is in keeping with what observed in solution. A comparative study of protein stability in solution and in crystallo is then carried out, monitoring the change in protein secondary structure at increasing temperature by Fourier transform infrared spectroscopy. The increased structural order of the crystalline state contributes to provide better resolved spectral components compared to those collected in solution and crucially, the crystalline samples display thermal stabilities in good agreement with the trend observed in solution. Overall, this work shows that protein stability and occurrence of pathological hidden states in crystals parallel their solution counterpart, confirming the interest of crystals as a platform for the biophysical characterization of processes such as unfolding and aggregation.

中文翻译:

晶体中的构象稳定性和动力学概括了溶液中的蛋白质行为

越来越多的证据表明,在许多情况下,蛋白质可以在结晶环境中保留其大部分功能和灵活性,并且目前有几种技术能够表征紧密排列的晶格中蛋白质的分子特性。有趣的是,在淀粉样前体的情况下,瞬时人口状态的存在(隐藏在常规晶体学研究中)可能与天然折叠的病理命运相关;天然状态的低折叠稳定性是聚集倾向的标志。然而,目前尚不清楚蛋白质的生物物理特性在多大程度上反映了在溶液中更常研究的蛋白质行为,例如瞬态构象的存在或以晶体为特征的蛋白质稳定性。这里,我们通过研究原型淀粉样蛋白生成系统、溶液中和微晶状态中的 β2-微球蛋白的一些生物物理特性来解决这个问题。通过将 NMR 化学位移与分子动力学模拟相结合,我们证实晶格中 β2-微球蛋白天然状态的构象动力学与在溶液中观察到的一致。然后进行溶液和晶体中蛋白质稳定性的比较研究,通过傅里叶变换红外光谱监测蛋白质二级结构随温度升高的变化。与溶液中收集的那些相比,结晶状态的增加的结构顺序有助于提供更好的解析光谱分量,并且至关重要的是,结晶样品显示出与溶液中观察到的趋势非常一致的热稳定性。总体而言,这项工作表明,蛋白质稳定性和晶体中病理隐藏状态的发生与其溶液对应物平行,证实了晶体作为展开和聚集等过程的生物物理表征平台的兴趣。
更新日期:2020-09-01
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