The relationship between protein crystal quality and growth kinetics was assessed by measuring the normal growth rates vs supersaturation of the (110) and (101) faces of dislocation-free tetragonal hen egg white lysozyme crystals at three precipitant concentrations, with NaCl as the precipitant. Assuming a two-dimensional birth and spreading nucleation mechanism, an increase in the surface free energy of the step edges was realized with increasing NaCl concentration, as established by decreases in the full width at half-maximum values of X-ray diffraction rocking curves obtained from crystals. These results demonstrate that controlling the surface free energy of the step edges is an important aspect of obtaining high-quality protein crystals. This work also proposes a mechanism for the observed improvements in the crystal quality, based on the reduced incorporation of impurities into the steps during crystal growth.

中文翻译：

---

控制表面自由能的高质量蛋白晶体的结晶技术

蛋白质晶体质量与生长动力学之间的关系通过在三种沉淀剂浓度下以NaCl作为沉淀剂测量无位错四方鸡蛋清溶菌酶晶体的（110）和（101）面的正常生长速率与过饱和度之间的关系进行评估。假设存在二维生散和成核机制，则随着NaCl浓度的增加，台阶边缘的表面自由能会增加，这是由获得的X射线衍射摇摆曲线的半最大值处的全宽度减小所确定的。从晶体。这些结果表明，控制台阶边缘的表面自由能是获得高质量蛋白质晶体的重要方面。这项工作还提出了一种观察到的晶体质量改善的机制，