Crystallization and preliminary X-ray crystallographic analysis of yeast arginyl-tRNA synthetase–yeast tRNAArg complexes
Résumé
Three different crystal forms of complexes between arginyl-tRNA synthetase from the yeast Saccharomyces cerevisae (yArgRS) and the yeast second major tRNAArg (tRNA^{\rm Arg}_{\rm ICG}) isoacceptor have been crystallized by the hanging-drop vapour-diffusion method in the presence of ammonium sulfate. Crystal form II, which diffracts beyond 2.2 Å resolution at the European Synchrotron Radiation Facility ID14-4 beamline, belongs to the orthorhombic space group P21212, with unit-cell parameters a = 129.64, b = 107.47, c = 71.38 Å. This crystal form presents the highest resolution obtained for an active form of an aminoacyl-tRNA synthetase–tRNA complex. The estimated Vm of 2.6 Å3 Da−1 indicates one molecule of complex in the asymmetric unit. The three crystal forms were solved by the molecular-replacement method using the coordinates of the free yArgRS.