高通量晶体学中提高模型准确性的测试。
A test of enhancing model accuracy in high-throughput crystallography.
作者信息
Arendall W Bryan, Tempel Wolfram, Richardson Jane S, Zhou Weihong, Wang Shuren, Davis Ian W, Liu Zhi-Jie, Rose John P, Carson W Michael, Luo Ming, Richardson David C, Wang Bi-Cheng
机构信息
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710-3711, USA.
出版信息
J Struct Funct Genomics. 2005;6(1):1-11. doi: 10.1007/s10969-005-3138-4.
The high throughput of structure determination pipelines relies on increased automation and, consequently, a reduction of time spent on interactive quality control. In order to meet and exceed current standards in model accuracy, new approaches are needed for the facile identification and correction of model errors during refinement. One such approach is provided by the validation and structure-improvement tools of the MOL: PROBITY: web service. To test their effectiveness in high-throughput mode, a large subset of the crystal structures from the SouthEast Collaboratory for Structural Genomics (SECSG) has used protocols based on the MOL: PROBITY: tools. Comparison of 29 working-set and 19 control-set SECSG structures shows that working-set outlier scores for updated Ramachandran-plot, sidechain rotamer, and all-atom steric criteria have been improved by factors of 5- to 10-fold (relative to the control set or to a Protein Data Bank sample), while quality of covalent geometry, R(work), R(free), electron density and difference density are maintained or improved. Some parts of this correction process are already fully automated; other parts involve manual rebuilding of conformations flagged by the tests as trapped in the wrong local minimum, often altering features of functional significance. The ease and effectiveness of this technique shows that macromolecular crystal structures from either traditional or high-throughput determinations can feasibly reach a new level of excellence in conformational accuracy and reliability.
结构测定流程的高吞吐量依赖于自动化程度的提高,因此需要减少用于交互式质量控制的时间。为了达到并超越当前模型准确性的标准,需要新的方法来在结构精修过程中轻松识别和纠正模型错误。MOL: PROBITY: 网络服务的验证和结构改进工具提供了这样一种方法。为了测试它们在高通量模式下的有效性,来自东南结构基因组学合作实验室(SECSG)的大量晶体结构子集使用了基于MOL: PROBITY: 工具的协议。对29个工作集和19个对照集SECSG结构的比较表明,更新后的拉氏图、侧链旋转异构体和全原子空间标准的工作集异常值分数提高了5到10倍(相对于对照集或蛋白质数据库样本),而共价几何结构、R(work)、R(free)、电子密度和差分密度的质量保持不变或有所提高。这个校正过程的一些部分已经完全自动化;其他部分涉及手动重建被测试标记为陷入错误局部最小值的构象,这通常会改变具有功能意义的特征。这项技术的简便性和有效性表明,来自传统或高通量测定的大分子晶体结构在构象准确性和可靠性方面可以切实达到一个新的卓越水平。