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-1) consists of 90 residues and differs from eukaryal EF-1s. The protein has been successfully crystallized using either microbatch-under-oil or vapour-diffusion methods. Crystals of native SsEF-1 diffract to 1.97 A ̊ resolution and belong to space group P21212, 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-1 at 1.83 A ̊ resolution. Model building using the phases derived from the MAD experiment is in progress.