The use of single-wavelength anomalous scattering to solve the crystal structure of a gramicidin A/caesium chloride complex.
The use of single-wavelength anomalous scattering to solve the crystal structure of a gramicidin A/caesium chloride complex.
复制标题
使用单波长反常散射解析短杆菌肽 A/氯化铯络合物的晶体结构。
DOI：
10.1107/s0108768190001161
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Ravikumar,K
中科院分区：
文献类型：
--
作者：
Wallace,BA;Hendrickson,WA;Ravikumar,K
摘要用单波长Cu Ka反常散射测定短杆菌肽A和氯化铯晶体复合物的结构。晶体中的不对称单元含有十五肽的四个独立单体（两个二聚体），空间群为P212~ 2~，a= 32.118（6），B= 52.103（12），c= 31.174（7）。这种结构福尔斯属于中等尺寸范围，对于这种结构，直接方法和多次同晶置换通常不能成功地获得相位信息。然而，利用Bijvoet差异和已掺入晶体中的铯原子的部分结构，可以获得关于这种晶体形式的信息。由于铯原子占主导地位的散射这些晶体，列入的弗里德尔伴侣的信息在受约束的最小二乘细化一直是必不可少的。这些研究将单波长反常散射相位测定的实用性推广到反常散射体的局部结构较大的大分子结构中。
Abstract Single-wavelength Cu Ka anomalous scattering has been used to determine the structure of a crystalline complex of gramicidin A and caesium chloride. The asymmetric unit in these crystals, with space group P212~ 2~ and a= 32.118 (6), b= 52.103 (12), c= 31.174 (7) A, contains four independent monomers (two dimers) of the pentadecapeptide. This structure falls in an intermediate size range for which direct methods and multiple isomorphous replacement are generally not successful for obtaining phase informa-tion. However, using the Bijvoet differences and the partial structure of the caesium atoms which have been incorporated in the crystals, it has been possible to obtain information on this crystal form. Because the caesium atoms dominate the scattering of these crystals, inclusion of the Friedel mate information in the restrained least-squares refinement has been essential. These studies extend the utility of single-wavelength anomalous-scattering phase determina-tion to a macromolecular structure in which the partial structure of the anomalous scatterer is large.