Protein crystallization and development of the apparatus

利用航天飞机在太空微重力环境下对鸡蛋清溶菌酶进行了结晶实验。根据气相扩散法的原理，使用结晶装置，在生长单斜晶体的结晶条件下，获得了2种形态不同的晶体。在相同的晶化条件下，晶体呈正交晶系。另一方面，除了四方晶体之外，在用于生长四方晶体的结晶条件下也生长了看起来是斜方晶体的晶体。在单斜晶体的两种不同形状中，一种是矩形形式，另一种是极薄的板状形式。他们很容易通过外表彼此区分开来。在太空实验中，后者晶体出现的可能性很大。由于这两种单晶晶体中的分子堆积 关于我们 然而，从X-射线晶体学分析的结果显示，nic溶菌酶是相同的排列，空间生长晶体和地面生长晶体之间的形态差异被认为是来自晶面生长速率的差异。与此相反，对于正交晶体，空间生长晶体的分子堆积与地面生长的四斜晶系或单斜晶系晶体在高于30 ° C的温度条件下转化的高温形式的分子堆积完全不同。曾有报道称出现了具有相同分子排列的斜方晶体，但晶体的分辨率仅限于6*，此后未见报道。接下来，太空中生长的四氢呋喃晶体与地面生长的晶体具有相同的分子堆积和相同的形态，结果发现，即使在太空微重力环境中，在相同的结晶条件下，也会出现不同空间群的晶体。在对来自三个不同空间群的六种晶体（空间和地球生长晶体的单斜晶系、正交晶系和四斜晶系）进行X射线晶体学分析后，比较了它们的分子结构。空间生长和地面生长的晶体虽然在分子中有一些相对分散的区域，但在所获得的分子结构之间没有发现显着差异。关于与蛋白质结合的水结构，三个高度有序的水分子通常保守在溶菌酶的铰链区。这些事实表明，蛋白质结构本身不受微重力的影响，但蛋白质分子在成核过程中的相互作用受到了显著影响。在空间上，认为蛋白质分子的表面特征，如蛋白质分子表面的变化和疏水区的分布，控制着晶体核形成过程中的分子间相互作用。少

Crystallization experiement of hen egg-white lysozyme was conducted by using the space shuttle under the microgravity environment in space. The crystallization apparatuses were used according to the principle of the vapor diffusion method.In the crystallization conditions for growing monoclinic crystals, 2 morphologically different kinds of crystals were obtained. Furthermore, orthorhombic crystal appeared under the same crystallization conditions. On the other hand, crystals which seemed to be the orthorhombic crystal were also grown under the crystallization conditions for growing tetragonal crystals in addition to the tetragonal crystal. Of the two different shapes of monoclinic crystals, one is a rectangular form and the other is an extremely thin plate-like form. They are easily distinguished from each other by their appearances. In the space experiments, there was a strong likelihood of the latter crystals appearing. Since the molecular packing in the crystal of these two monocli … More nic lysozymes, however, revealed to be the same arrangement from the results of X-ray crystallographic analysis, the difference in the morphology between the space- and ground-grown crystals is considered to be derived from difference in the growth rate of the crystal plane. Regarding orthorhombic crystals, in contrast, the molecular packing of the space-grown crystals were quite different from that of the high temperature forms which are transformed under the temperature conditions higher than 30ﾟC from the ground-grown tetragonal or monoclinic crystals. It has been reported that the orthorhombic crystals possessing the same molecular arrangement appearred, but the resolution of the crystals is limited to 6* and no more report has been published thereafter. Next, the space-grown tetragonal crystals had the same molecular packing in the crystals as well as the same morphology as the ground-grown crystals.As the results, it turned out that crystals of the different space group happened to appear even under the same crystallization conditions in a microgravity environment in space. After X-ray crystallographic analyzes of six crystals from the three different space groups (monoclinic, orthorhombic and tetragonal forms of the space- and earth-grown crystals), their molecular structures were compared. Significant differences among the obtained molecular structures were not found between the space- and ground-grown crystals although they had some relatively fractuated regions in the molecule. Regarding the water structure bound to the protein, three highly ordered water molecules were commonly conserved in the hinge region of lysozyme. These facts suggest that the protein structure itself was not influenced by the microgravity but that the interaction of the protein molecules in the nucleation process was significantly affected. In space, it is assumed that the surface characteristics of the protein molecule e.g.the distributions of the change and the hydrophobic region on the surface of the protein molecule control the intermolecular interactions in the formation of crystal neuclei. Less