Cryoannealing-induced space-group transition of crystals of the carbonic anhydrase psCA3

Cryoannealing has been demonstrated to improve the diffraction quality and resolution of crystals of the β-carbonic anhydrase psCA3 concomitant with a change in space group. After initial flash-cooling in a liquid-nitrogen cryostream an X-ray diffraction data set from a psCA3 crystal was indexed in space group P21212 and was scaled to 2.6 Å resolution, but subsequent cryoannealing studies revealed induced protein rearrangements in the crystal contacts, which transformed the space group to I222, with a corresponding improvement of 0.7 Å in resolution. Although the change in diffraction resolution was significant, only minor changes in the psCA3 structure, which retained its catalytic `open' conformation, were observed. These findings demonstrate that cryoannealing can be successfully utilized to induce higher diffraction-quality crystals while maintaining enzymatically relevant conformations and may be useful as an experimental tool for structural studies of other enzymes where the initial diffraction quality is poor.

Source: Acta Crystallographica Section F - June 27, 2016 Category: Biochemistry Authors: Pinard, M.A.Kurian, J.J.Aggarwal, M.Agbandje-McKenna, M.McKenna, R. Tags: β -carbonic anhydrase Pseudomonas aeruginosa cryoannealing crystal packing research communications Source Type: research