Joint X-ray and neutron refinement with phenix.refine
Joint X-ray and neutron refinement with phenix.refine
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DOI：
10.1107/s0907444910026582
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发表时间：
2010-11-01
影响因子：
2.2
通讯作者：
Adams, Paul D.
中科院分区：
文献类型：
--
作者：
Afonine, Pavel V.;Mustyakimov, Marat;Adams, Paul D.
蛋白质数据库中大约85%的结构已经使用X射线晶体学解决，使其成为大分子三维结构测定的领先方法。该方法的局限性之一是典型的数据质量（分辨率）不允许直接确定H原子的位置。大多数氢的位置可以从其他原子的位置推断出来，因此可以很容易地作为先验知识包括在结构模型中。然而，在大分子的生物活性位点中可能不是这种情况，其中氢的存在和位置对酶促机制至关重要。这使得中子晶体学在生物学中的应用特别重要，因为H原子可以在实验中子散射密度图中清楚地定位。毫无例外，当确定中子结构时，相应的X射线结构也是已知的，使得可以使用两个数据集导出完整的结构。在这里，实施晶体结构细化程序，包括X射线和中子数据（单独或共同）在PHENIX系统中进行描述。
Approximately 85% of the structures deposited in the Protein Data Bank have been solved using X-ray crystallography, making it the leading method for three-dimensional structure determination of macromolecules. One of the limitations of the method is that the typical data quality (resolution) does not allow the direct determination of H-atom positions. Most hydrogen positions can be inferred from the positions of other atoms and therefore can be readily included into the structure model as a priori knowledge. However, this may not be the case in biologically active sites of macromolecules, where the presence and position of hydrogen is crucial to the enzymatic mechanism. This makes the application of neutron crystallography in biology particularly important, as H atoms can be clearly located in experimental neutron scattering density maps. Without exception, when a neutron structure is determined the corresponding X-ray structure is also known, making it possible to derive the complete structure using both data sets. Here, the implementation of crystallographic structure-refinement procedures that include both X-ray and neutron data (separate or jointly) in the PHENIX system is described.