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

The nucleotide-exchange factor isolated from the hyperthermophilic archaeon, S. solfataricus (SsEF-1b), consists of 90 residues and differs from eukaryal EF-1bs. Here, the protein was successfully crystd. using either microbatch-under-oil or vapor-diffusion methods. Crystals of native SsEF-1b diffracted to 1.97 .ANG. resoln. and belonged to space group P21212, with unit-cell parameters a = 106.46, b = 54.87, and c = 44.03 Diffraction data were also collected from a selenomethionine deriv. of SsEF-1b at 1.83 .ANG. resoln. Model building using the phases derived from the MAD expt. is in progress.