Crystallization and preliminary X-ray crystallographic analysis of the Sulfolobus solfataricus nucleotide-exchange factor 1beta.

The nucleotide-exchange factor isolated from the hyperthermophilic archaeon Sulfolobus solfataricus (SsEF-1beta) consists of 90 residues and differs from eukaryal EF-1betas. The protein has been successfully crystallized using either microbatch-under-oil or vapour-diffusion methods. Crystals of native SsEF-1beta diffract to 1.97 A resolution and belong to space group P2(1)2(1)2, with unit-cell parameters a = 106.46, b = 54.87, c = 44.03 A. Diffraction data have also been collected from a selenomethionine derivative of SsEF-1beta at 1.83 A resolution. Model building using the phases derived from the MAD experiment is in progress.