CRYSTALLIZATION OF THERMUS-THERMOPHILUS HISTIDYL-TRANSFER-RNA SYNTHETASE AND ITS COMPLEX WITH TRNA(HIS)

Histidyl-tRNA synthetase (HisRS) has been purified from the extreme thermophile Thermus thermophilus. The protein has been crystallized separately with histidine and with its cognate tRNA(His). Both crystals have been obtained using the vapor diffusion method with ammonium sulphate as precipitant. The crystals of HisRS with histidine belong to the spacegroup P2(1)2(1)2 with cell parameters alpha = 171.3 Angstrom, b = 214.7 Angstrom, c = 49.3 Angstrom, alpha = beta = gamma = 90 degrees. A complete data set to a resolution of 2.7 Angstrom with an R(merge) on intensities of 4.1% has been collected on a single frozen crystal. A partial data set collected on a crystal of HisRS in complex with tRNA(His) shows that the crystals are tetragonal with cell parameters a = b = 232 Angstrom, c = 559 Angstrom, alpha = beta = gamma = 90 degrees and diffract to about 4.5 Angstrom resolution. (C) 1995 Wiley-Liss, Inc.