Pozharski Edwin
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
Acta Crystallogr D Biol Crystallogr. 2011 Nov;67(Pt 11):966-72. doi: 10.1107/S090744491103914X. Epub 2011 Oct 19.
It is demonstrated that the crystallographic models of macromolecules may appear to diverge upon extended refinement against experimental data. Two regimes are identified for this phenomenon. Firstly, at higher resolution the apparent instability of the resulting models is shown to originate from the relatively small fraction of disordered atoms present in the initial model. Secondly, at lower resolution additional refinement instability may arise from insufficiently strong geometry restraints. The convergence of crystallographic refinement is proposed as one of the possible criteria in selecting a specific refinement strategy and in model validation.
结果表明，在根据实验数据进行长时间精修后，大分子的晶体学模型可能会出现分歧。这种现象可分为两种情况。首先，在较高分辨率下，所得模型明显的不稳定性被证明源于初始模型中存在的相对少量的无序原子。其次，在较低分辨率下，额外的精修不稳定性可能源于几何约束不够强。晶体学精修的收敛性被提议作为选择特定精修策略和模型验证的可能标准之一。
