Crystallization and preliminary X-ray analysis of the C-terminal RNase III domain of human Dicer.

Human Dicer protein contains two RNase III domains (RNase IIIa and RNase IIIb) which are involved in the production of short interfering RNAs (siRNAs). The C-terminal RNase III domain (RNase IIIb) of human Dicer was expressed, purified and crystallized by the sitting-drop vapour-diffusion method. The crystals belonged to space group C222(1), with unit-cell parameters a = 88.6, b = 199.7, c = 119.6 angstroms, and diffracted X-rays to 2.0 angstroms resolution. The asymmetric unit contained three molecules of the RNase IIIb and the solvent content was 67%.