Resolution of the phase-ambiguity problem in the centrosymmetric P [1] space group by Monte Carlo methods.
Resolution of the phase-ambiguity problem in the centrosymmetric P [1] space group by Monte Carlo methods.
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DOI：
10.1107/s0108767300008849
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发表时间：
2000-11
期刊：
影响因子：
--
通讯作者：
M. Delarue
中科院分区：
文献类型：
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作者：
M. Delarue
模拟退火方法已被用来解决中心对称P空间群中的相位模糊问题。首先，基于塞尔方程的能量函数的介绍和正式比较与经典的自旋系统。能源景观进行了详细的研究，并彻底测试了几个能源标准的有效性。经典的蒙特卡罗方法被证明是成功的，使用多启动优化的塞尔分数，沿着与其他精力充沛的标准的额外监测。这些涉及在没有包络信息的情况下在倒易空间中的Terwilliger图质量指数，以及如果分子的形状已知则包络分数。因此，P空间群固有的相位模糊问题通过蒙特卡罗方法在技术上得到了解决。该方法也应该解决蛋白质晶体学的SIR方法中的相位模糊性。
Simulated-annealing methods have been used to resolve the phase-ambiguity problem in the centrosymmetric P¿bar¿1¿ space group. First, an energy function based on the Sayre equation is introduced and a formal comparison with classical spin systems is drawn. The energy landscape is studied in detail and the validity of several energy criteria thoroughly tested. Classical Monte Carlo methods proved to be successful using a multistart optimization of the Sayre score, along with the additional monitoring of other energetic criteria. These involved the Terwilliger map quality index in reciprocal space in the absence of envelope information, and an envelope score if the shape of the molecule is known. The inherent phase-ambiguity problem of the P¿bar¿1¿ space group was therefore technically solved by Monte Carlo methods. The method should also work to resolve phase ambiguity in the SIR method of protein crystallography.