Thompson Michael C
Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, Box 2240, 600 16th Street, S476, San Francisco, CA, 94158, USA.
Methods Mol Biol. 2017;1607:185-217. doi: 10.1007/978-1-4939-7000-1_8.
Macromolecular crystals are prone to a number of pathologies that result from aberrant molecular packing. Two common pathologies encountered in macromolecular crystals are rigid-body disorder and twinning. When a crystal displays one of these pathologies, its diffraction pattern is altered in a way that generally complicates structure determination. The severity of the underlying abnormalities varies from case to case, and sometimes the resulting alterations to the diffraction pattern are immediately obvious, while at other times they may go entirely unnoticed. Structure determination from a crystal that suffers from disorder or twinning may or may not be possible, depending on the specific nature of the pathology, and on how the data are handled. This chapter provides an introduction to these pathologies, with an emphasis on providing guidelines for identifying and overcoming them when they pose a threat to successful structure determination.
大分子晶体容易出现许多由异常分子堆积导致的病理现象。大分子晶体中常见的两种病理现象是刚体无序和孪晶。当晶体出现这些病理现象之一时，其衍射图样会发生改变，这通常会使结构测定变得复杂。潜在异常的严重程度因情况而异，有时对衍射图样产生的改变会立即显现出来，而在其他时候可能完全不被注意到。根据病理现象的具体性质以及数据处理方式，从患有无序或孪晶的晶体中进行结构测定可能可行，也可能不可行。本章介绍这些病理现象，重点是提供在它们对成功的结构测定构成威胁时识别和克服它们的指导原则。
