AI 中文总结
本研究结合声悬浮与X射线散射技术，实时监测铁蛋白在蒸发液滴中的结晶过程，发现PEG分子量可调控结晶途径并抑制脱水导致的晶体失序，为提升蛋白质晶体稳定性提供简单策略。
AI 中文摘要
理解蛋白质结晶途径对于在结构生物学、材料科学和制药应用中控制结晶过程至关重要。经典成核理论并不能完全描述包括铁蛋白在内的若干蛋白质的结晶过程。在此，我们将声悬浮技术与小角和广角X射线散射（SAXS和WAXS）相结合，以监测铁蛋白在蒸发中的聚乙二醇（PEG）水溶液中的结晶过程。声悬浮使液滴快速经历广泛的蛋白质和聚合物浓度范围，从而能够在蒸发过程中对结晶进行时间分辨测量。散射数据表明，铁蛋白晶体在蒸发过程中形成，并在进一步脱水后失去其晶体有序性。改变PEG分子量可在不同的结晶途径之间切换：一种由吸引性蛋白质-蛋白质相互作用主导，另一种由排斥性相互作用和体积排斥效应主导。此外，我们发现较低分子量的PEG（1000 g/mol）抑制了较高分子量PEG（6000 g/mol）所观察到的脱水诱导的晶体有序性丧失，为改善蛋白质晶体稳定性提供了一种简单策略。
英文摘要
Understanding protein crystallization pathways is essential for controlling crystallization in structural biology, materials science, and pharmaceutical applications. Classical nucleation theory does not fully capture crystallization processes for several proteins, including ferritin. Here, we combine acoustic levitation with small- and wide-angle X-ray scattering (SAXS and WAXS) to monitor ferritin crystallization in evaporating aqueous polyethylene glycol (PEG) solutions. Acoustic levitation rapidly drives the droplets through a broad range of protein and polymer concentrations, enabling time-resolved measurements of crystallization during evaporation. The scattering data show that ferritin crystals form during evaporation and subsequently lose their crystalline order upon further dehydration. Varying the PEG molecular weight switches between distinct crystallization pathways: one dominated by attractive protein-protein interactions and another dominated by repulsive interactions and excluded-volume effects. Furthermore, we find that lower molecular weight PEG (1000 g/mol) suppresses the dehydration-induced loss of crystalline order observed for higher molecular weight PEG (6000 g/mol), providing a simple strategy for improving protein crystal stability.
