Crystallization and preliminary X-ray crystallographic analysis of type IIdehydroquinase from Helicobacter pylori

The enzyme 3-dehydroquinase catalyzes the interconversion of 3-dehydroquina te and 3-dehydroshikimate. The enzymes are classified into two groups, type I and type II, which have different biochemical and biophysical properties and act with different mechanisms. The type II dehydroquinase of Helicobac ter pylori, a dodecameric enzyme, was overexpressed in Escherichia coli. Th e recombinant protein has been crystallized at 296 K using polyethylene gly col (PEG) 4000 as a precipitant. Native X-ray diffraction data have been co llected to 2.5 Angstrom resolution using synchrotron radiation. The crystal s are cubic and belong to the space group P4(2)32, with unit-cell parameter s a = b = c = 98.91 Angstrom. The asymmetric unit contains one subunit of r ecombinant type II dehydroquinase, with a corresponding V-M of 2.18 Angstro m (3) Da(-1) and a solvent content of 43.6%.