title: Structure of the 'open' form of Aspergillus nidulans 3-dehydroquinate synthase at 1.7 A resolution from crystals grown following enzyme turnover.
abstract: Crystallization of Aspergillus nidulans 3-dehydroquinate synthase (DHQS), following turnover of the enzyme by addition of the substrate DAHP, gave a new crystal form (form J). Although the crystals have dimensions of only 50 x 20 x 5 micro m, they are well ordered, diffracting to 1.7 A. The space group is C222(1), with unit-cell parameters a = 90.0, b = 103.7, c = 177.4 A. Structure determination and refinement to R = 0.19 (R(free) = 0.25) shows the DHQS is in the 'open' form with the substrate site unoccupied but with some loop regions perturbed. Previous crystals of open-form DHQS only diffracted to 2.5 A resolution. The use of enzyme turnover may be applicable in other systems in attempts to improve crystal quality.
authors.affiliation: Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, England.
authors.forename: C E
authors.initials: CE
authors.lastname: Nichols
authors.forename: A R
authors.initials: AR
authors.lastname: Hawkins
authors.forename: D K
authors.initials: DK
authors.lastname: Stammers
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology*; D001671:Biochemistry / Q000379:methods; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D019761:Phosphorus-Oxygen Lyases / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D040681:Structural Homology, Protein; D013400:Sugar Acids / Q000737:chemistry / Q000378:metabolism
chemical_list: C017182:5-dehydro-3-deoxy-D-arabino-heptulosonic acid-7-phosphate; D013400:Sugar Acids; C020001:3-dehydroquinate synthetase; D019761:Phosphorus-Oxygen Lyases