Growth kinetics, diffraction properties and effect of agarose on the stability of a novel crystal form of Thermus thermophilus aspartyl-tRNA synthetase-1

Growth kinetics and diffraction properties of monoclinic crystals of eubact erial Thermus thermophilus aspartyl-tRNA synthetase-1 (AspRS-1) prepared in the presence of polyethylene glycol and agarose are studied. Their solubil ity and two-dimensional phase diagram are compared with those of orthorhomb ic crystals which grow in the presence of sodium formate or ammonium sulfat e. The growth mechanism of the novel crystals was monitored by atomic force microscopy. The gel stabilizes the crystal lattice under the cryogenic con ditions used for structure determination at high resolution.