Kierzek A M, Pokarowski P, Zielenkiewicz P
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw.
Biophys Chem. 2000 Sep 15;87(1):43-61. doi: 10.1016/s0301-4622(00)00179-4.
A microscopic, reversible model to study protein crystal nucleation and growth is presented. The probability of monomer attachment to the growing crystal was assumed to be proportional to the protein volume fraction and the orientational factor representing the anisotropy of protein molecules. The rate of detachment depended on the free energy of association of the given monomer in the lattice, as calculated from the buried surface area. The proposed algorithm allowed the simulation of the process of crystal growth from free monomers to complexes having 10(5) molecules, i.e. microcrystals with already formed faces. These simulations correctly reproduced the crystal morphology of the chosen model system--the tetragonal lysozyme crystal. We predicted the critical size, after which the growth rate rapidly increased to approximately 50 protein monomers. The major factors determining the protein crystallisation kinetics were the geometry of the protein molecules and the resulting number of kinetics traps on the growth pathway.
本文提出了一个用于研究蛋白质晶体成核和生长的微观可逆模型。假设单体附着到生长晶体上的概率与蛋白质体积分数以及代表蛋白质分子各向异性的取向因子成正比。脱离速率取决于晶格中给定单体的结合自由能，该自由能由埋藏表面积计算得出。所提出的算法能够模拟从游离单体到具有10⁵个分子的复合物（即已形成晶面的微晶）的晶体生长过程。这些模拟正确地再现了所选模型系统——四方溶菌酶晶体的晶体形态。我们预测了临界尺寸，超过该尺寸后生长速率迅速增加至约50个蛋白质单体。决定蛋白质结晶动力学的主要因素是蛋白质分子的几何形状以及生长途径上产生的动力学陷阱数量。
