Dauter Miroslawa, Dauter Zbigniew
Basic Science Program, Leidos Biomedical Research, Inc., Argonne National Laboratory, Argonne, IL, 60439, USA.
Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL, 60439, USA.
Methods Mol Biol. 2017;1607:349-356. doi: 10.1007/978-1-4939-7000-1_14.
Due to the availability of many macromolecular models in the Protein Data Bank, the majority of crystal structures are currently solved by molecular replacement. However, truly novel structures can only be solved by one of the versions of the special-atom method. The special atoms such as sulfur, phosphorus or metals could be naturally present in the macromolecules, or could be intentionally introduced in a derivatization process. The isomorphous and/or anomalous scattering of X-rays by these special atoms is then utilized for phasing. There are many ways to obtain potentially useful derivatives, ranging from the introduction of special atoms to proteins or nucleic acids by genetic engineering or by chemical synthesis, to soaking native crystals in solutions of appropriate compounds with heavy and/or anomalously scattering atoms. No approach guarantees the ultimate success and derivatization remains largely a trial-and-error process. In practice, however, there is a very good chance that one of a wide variety of the available procedures will lead to successful structure solution.
由于蛋白质数据库中存在许多大分子模型，目前大多数晶体结构是通过分子置换法解析的。然而，真正新颖的结构只能通过特殊原子法的其中一种变体来解析。诸如硫、磷或金属等特殊原子可能天然存在于大分子中，或者可以在衍生化过程中有意引入。然后利用这些特殊原子对X射线的同晶型和/或反常散射来进行相位测定。获得潜在有用衍生物的方法有很多，从通过基因工程或化学合成将特殊原子引入蛋白质或核酸，到将天然晶体浸泡在含有重原子和/或反常散射原子的适当化合物溶液中。没有一种方法能保证最终成功，衍生化在很大程度上仍然是一个反复试验的过程。然而，在实际操作中，各种各样可用的程序中很有可能有一种会导致成功解析结构。
