Ice in biomolecular cryocrystallography.

摘要: Diffraction data acquired from cryocooled protein crystals often include diffraction ice. Analysis of ice three proteins shows that the formed within solvent cavities during rapid cooling is comprised a stacking-disordered mixture hexagonal and cubic planes, with plane fraction increasing cryoprotectant concentration rate. Building on work Thorn coworkers [Thorn et al. (2017), Acta Cryst. D73, 729–727], revised metric defined for detecting deposited structure-factor data, this validated using full-frame Integrated Resource Reproducibility in Macromolecular Crystallography. Using improved algorithms, an analysis random sample 89 827 PDB entries collected at cryogenic temperatures indicates roughly 16% show evidence contamination, increases content maximum solvent-cavity size. By examining diffraction-peak positions which perturbations are observed, it found 25% exhibit primarily character, indicating inadequate rates and/or concentrations were used, while remaining 75% or character.