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

ABSTRACT: Cryoannealing has been demonstrated to improve the diffraction quality and resolution of crystals of the ?-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.

SUBMITTER: Pinard MA 

PROVIDER: S-EPMC4933009 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature