Improved Success of Sparse Matrix Protein Crystallization Screening with Heterogeneous Nucleating Agents

Abstract

BACKGROUND Crystallization is a major bottleneck in the process of macromolecular structure determination by X-ray crystallography. Successful crystallization requires the formation of nuclei and their subsequent growth to crystals of suitable size. Crystal growth generally occurs spontaneously in a supersaturated solution as a result of homogenous nucleation. However, in a typical sparse matrix screening experiment, precipitant and protein concentration are not sampled extensively, and supersaturation conditions suitable for nucleation are often missed. METHODOLOGY/PRINCIPAL FINDINGS We tested the effect of nine potential heterogenous nucleating agents on crystallization of ten test proteins in a sparse matrix screen. Several nucleating agents induced crystal formation under conditions where no crystallization occurred in the absence of the nucleating agent. Four nucleating agents: dried seaweed; horse hair; cellulose and hydroxyapatite, had a considerable overall positive effect on crystallization success. This effect was further enhanced when these nucleating agents were used in combination with each other. CONCLUSIONS/SIGNIFICANCE Our results suggest that the addition of heterogeneous nucleating agents increases the chances of crystal formation when using sparse matrix screens.

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@article{Thakur2007ImprovedSO, title={Improved Success of Sparse Matrix Protein Crystallization Screening with Heterogeneous Nucleating Agents}, author={Anil S. Thakur and Gautier Robin and Gregor Gun{\vc}ar and Neil F. W. Saunders and Janet Newman and Jennifer L. Martin and Bostjan Kobe}, journal={PLoS ONE}, year={2007}, volume={2}, pages={254 - 265} }