Temperature-Dependent Interactions Explain Normal and Inverted Solubility in a γD-Crystallin Mutant
Temperature-Dependent Interactions Explain Normal and Inverted Solubility in a γD-Crystallin Mutant
复制标题
温度依赖性相互作用解释了γD-晶状体蛋白突变体的正常和反向溶解度
DOI：
10.1016/j.bpj.2019.07.019
复制
发表时间：
2019
影响因子：
3.4
通讯作者：
McManus, Jennifer J.
中科院分区：
文献类型：
--
作者：
Khan, Amir R.;James, Susan;Quinn, Michelle K.;Altan, Irem;Charbonneau, Patrick;McManus, Jennifer J.
蛋白质晶体的制备是蛋白质结构表征的主要瓶颈。为了超越大规模筛选，蛋白质结晶的合理策略至关重要。了解蛋白质表面的化学各向异性（或斑块），由于与溶剂接触的氨基酸侧链的变化，有助于在晶格中形成蛋白质-蛋白质接触是预测和优化结晶的主要障碍。复杂的理论模型相对缺乏，包括足够的细节来联系集体行为，在蛋白质相图中捕获，分子水平的细节，从高分辨率的结构信息确定，是另一个障碍。在这里，我们提出了γ D-晶状体蛋白的P23 T + R36 S突变体的两种晶体结构，每一种都具有相反的溶解度行为：一种在加热时熔化，另一种在冷却时熔化。当结合蛋白质相图和一个定制的补丁颗粒模型，我们表明，一个单一的温度依赖性的相互作用是足以稳定的反转溶解度晶体。在P23 T取代位点的这种接触与遗传性白内障有关，并在分子水平上揭示了蛋白质溶解度降低和逆行的起源。我们的研究结果表明，这里采用的方法可能会提出一个生产性的策略，合理化的蛋白质结晶。
Protein crystal production is a major bottleneck in the structural characterization of proteins. To advance beyond large-scale screening, rational strategies for protein crystallization are crucial. Understanding how chemical anisotropy (or patchiness) of the protein surface, due to the variety of amino-acid side chains in contact with solvent, contributes to protein-protein contact formation in the crystal lattice is a major obstacle to predicting and optimizing crystallization. The relative scarcity of sophisticated theoretical models that include sufficient detail to link collective behavior, captured in protein phase diagrams, and molecular-level details, determined from high-resolution structural information, is a further barrier. Here, we present two crystal structures for the P23T + R36S mutant ofγD-crystallin, each with opposite solubility behavior: one melts when heated, the other when cooled. When combined with the protein phase diagram and a tailored patchy particle model, we show that a single temperature-dependent interaction is sufficient to stabilize the inverted solubility crystal. This contact, at the P23T substitution site, relates to a genetic cataract and reveals at a molecular level the origin of the lowered and retrograde solubility of the protein. Our results show that the approach employed here may present a productive strategy for the rationalization of protein crystallization.