title: 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 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, PO Box 100245, Gainesville, FL 32610, USA.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Pinard
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, PO Box 100245, Gainesville, FL 32610, USA.
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Kurian
authors.affiliation: Division of Biology and Soft Matter, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Mayank
authors.initials: M
authors.lastname: Aggarwal
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, PO Box 100245, Gainesville, FL 32610, USA.
authors.forename: Mavis
authors.initials: M
authors.lastname: Agbandje-McKenna
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, PO Box 100245, Gainesville, FL 32610, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: McKenna
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D024403:Carbonic Anhydrase III / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D008958:Models, Molecular; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000201:enzymology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D024403:Carbonic Anhydrase III
keywords: Pseudomonas aeruginosa; cryoannealing; crystal packing; β-carbonic anhydrase