Crystallization and characterization of a fragment of pseudouridine synthase RluC from Escherichia coli.

RluC from E. coli is the enzyme responsible for catalyzing the isomerization of uridines 955, 2504 and 2580 in 23S rRNA to pseudouridine. Histidine-tagged RluC was cloned, overexpressed and purified by nickel-affinity chromatography. A proteolytically derived fragment of the enzyme consisting of residues 89-319 has been shown to retain catalytic activity. Crystals of this fragment, grown by precipitation with sodium acetate at pH 8.0, belong to space group P321, with unit-cell dimensions a = b = 97.1, c = 86.3 A and have two molecules in the crystallographic asymmetric unit. The flash-frozen crystals diffract X-rays to at least 2.3 A resolution and appear suitable for crystal structure determination.