Direct determination of the nucleation rates of protein crystals
Direct determination of the nucleation rates of protein crystals
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DOI：
10.1021/jp992786x
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发表时间：
1999-12-09
影响因子：
3.3
通讯作者：
Vekilov, PG
中科院分区：
文献类型：
--
作者：
Galkin, O;Vekilov, PG
我们发展了一种直接测定均相成核稳态速率的新方法。该方法适用于蛋白质或其他具有随温度变化的可溶性慢生长材料的溶液的结晶、聚集和类似的一级相变的研究。溶液过饱和度的温度T控制允许快速过饱和度从诱导成核的水平变化到没有成核发生的水平，但现有晶体生长到可检测的尺寸。这样，在晶体生长导致的溶液耗尽变得明显之前，只有在恒定过饱和度的第一个T设置时才发生成核。我们用惰性油覆盖成核溶液，抑制溶液-空气界面的成核。为了获得本质随机成核过程的可重现的统计特性，在相同的条件下进行大量的同时试验。首先，典型结晶条件下蛋白质溶菌酶模型的成核数据表明，蛋白质晶体成核可能发生在或甚至超出经典的连续成核模型的适用范围。
We have developed a novel method for direct determination of the steady-state rates of homogeneous nucleation. The method is applicable to studies of crystallization, aggregation, and similar first-order phase transitions in solutions of proteins or other soluble slow-growing materials with temperature-dependent solubility. Temperature T control of the solution supersaturation allows fast supersaturation changes from a level inductive of nucleation to a level where no nucleation occurs, but existing crystals grow to detectable dimensions. In this way, nucleation takes place only at the first T setting at a constant supersaturation before solution depletion due to crystal growth becomes significant. We use inert oil to cover nucleating solutions and suppress nucleation on the solution-air interface. To obtain reproducible statistical characteristics of the intrinsically random nucleation process, a large number of simultaneous trials take place under identical conditions. First data for the nucleation of the model protein lysozyme under typical crystallization conditions show that protein crystal nucleation may be occurring at or even beyond the boundary of applicability of classical, continuum nucleation models.