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Should we remediate small molecule structures? If so, who should do it?
Crystallography Reviews ( IF 2.0 ) Pub Date : 2018-09-10 , DOI: 10.1080/0889311x.2018.1508209
Carl H. Schwalbe 1, 2
Affiliation  

ABSTRACT Problems can arise in crystallographic databases with errors and omissions in the representation of data that impede searches, and with errors in the actual data. While the Cambridge Crystallographic Data Centre with its Improvement Projects has solved many of the first category of problems, errors in atomic coordinates and other crystallographic data are surprisingly common. Although modern software warns of many types of error, such errors appear even in recently deposited Crystallographic Information Files. Richard Marsh found many examples of missed symmetry in assignment of the space group; such errors are now waning. Hydrogen atoms are commonly placed in calculated positions. Particularly for OH and NH groups involved in hydrogen bonds, occupancy factors may need to be reduced to 0.5 or the hydrogen atom positions may require amendment. Examples of acids and imidazole derivatives are provided, showing that sometimes only consideration of bond distances and angles at the heteroatom can distinguish between OH or NH and unprotonated O or N. Significant work by other researchers correcting mis-positioned hydrogen atoms in dihydrogen phosphates and water aggregates as well as mis-identified elements is also summarized. This review concludes with some suggestions for more comprehensive detection and correction of errors in deposited data.

中文翻译:

我们应该修复小分子结构吗?如果是这样,谁应该做?

摘要 晶体学数据库中可能会出现问题,因为数据表示中的错误和遗漏会阻碍搜索,以及实际数据中的错误。虽然剑桥晶体学数据中心及其改进项目已经解决了许多第一类问题,但原子坐标和其他晶体学数据中的错误却出奇地普遍。尽管现代软件会警告多种类型的错误,但即使在最近存放的晶体信息文件中也​​会出现此类错误。理查德·马什 (Richard Marsh) 发现了许多在分配空间群时丢失对称性的例子;这种错误现在正在减少。氢原子通常放置在计算位置。特别是对于涉及氢键的 OH 和 NH 基团,占用因子可能需要减少到 0。5 或氢原子位置可能需要修改。提供了酸和咪唑衍生物的例子,表明有时仅考虑杂原子上的键距和角度就可以区分 OH 或 NH 以及未质子化的 O 或 N。其他研究人员的重要工作纠正了磷酸二氢盐和水中的错误定位的氢原子还总结了聚合以及错误识别的元素。本综述最后提出了一些建议,以便更全面地检测和纠正存放数据中的错误。还总结了其他研究人员纠正磷酸二氢盐和水聚集体中错误定位的氢原子以及错误识别元素的重要工作。本综述最后提出了一些建议,以便更全面地检测和纠正存放数据中的错误。还总结了其他研究人员纠正磷酸二氢盐和水聚集体中错误定位的氢原子以及错误识别元素的重要工作。本综述最后提出了一些建议,以便更全面地检测和纠正存放数据中的错误。
更新日期:2018-09-10
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