Diffuse scattering resulting from macromolecular frustration
Diffuse scattering resulting from macromolecular frustration
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DOI：
10.1107/s0108768111037542
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发表时间：
2011-12-01
影响因子：
1.9
通讯作者：
Taylor, Ian A.
中科院分区：
文献类型：
--
作者：
Welberry, T. R.;Heerdegen, A. P.;Taylor, Ian A.
在来自猫泡沫病毒的 Gag 蛋白 N 末端片段晶体的衍射图案中，观察到以布拉格位置周围的扩散环形式出现的独特扩散散射。结果表明，这些是由于分子试图堆积在空间群 P6(1)22 的三角形 b-c 网格上时几何挫败引起的。为了解释强烈的漫散射，晶体必须包含占据障碍，使得每个晶胞包含两种不同的分子排列 A 和 B 中的一种或另一种。之所以会出现挫败感，是因为最近邻堆积更喜欢相邻晶胞为 AB 或 BA，而这不能同时在三角形的所有三个边上实现。为了解释倒数部分 hk5n（其中 n = 整数）仅包含布拉格峰的观察结果，A 和 B 必须是相同的分子排列，仅相差 0.2c。讨论了这种无序对于通过常规技术解析蛋白质结构的影响以及为此目的使用漫散射的可能性。
Distinctive diffuse scattering in the form of diffuse rings around Bragg positions has been observed in the diffraction patterns of a crystal of the N-terminal fragment of the Gag protein from Feline Foamy Virus. It is shown that these are caused by geometric frustration as molecules try to pack on the triangular b-c mesh of the space group P6(1)22. In order to explain the strong diffuse scattering it is necessary for the crystal to contain occupational disorder such that each unit cell contains one or other of two different molecular arrangements, A and B. The frustration arises because the nearest-neighbour packing prefers neighbouring cells to be AB or BA, which cannot be achieved on all three sides of a triangle simultaneously. To explain the observation that reciprocal sections hk5n, where n = integer, contain only Bragg peaks it is necessary that A and B are identical molecular arrangements differing only by a translation of 0.2c. The implications of the disorder for solving the structure of the protein by conventional techniques as well as the possibility of using the diffuse scattering for this purpose are discussed.