The current approach to initial crystallization screening of proteins is under-sampled

Protein crystallization conditions that resulted in crystal structures published by scientists at the MRC Laboratory of Molecular Biology (MRC-LMB, Cambridge, UK) have been analysed. It was observed that the more often a crystallization reagent had been used to formulate the initial conditions, the more often it was found in the reported conditions that yielded diffraction quality crystals. The present analysis shows that, despite the broad variety of reagents, they have the same impact overall on the yield of crystal structures. More interestingly, the correlation implies that, although the initial crystallization screen may be considered very large, it is an under-sampled combinatorial approach.