X-ray diffraction analysis of a human tRNA(Gly) acceptor-stem microhelix isoacceptor at 1.18 A resolution.

Interest has been focused on comparative X-ray structure analyses of different tRNA(Gly) acceptor-stem helices. tRNA(Gly)/glycyl-tRNA synthetase belongs to the so-called class II system, in which the tRNA identity elements consist of simple and unique determinants that are located in the tRNA acceptor stem and the discriminator base. Comparative structure investigations of tRNA(Gly) microhelices provide insight into the role of tRNA identity elements. Predominant differences in the structures of glycyl-tRNA synthetases and in the tRNA identity elements between prokaryotes and eukaryotes point to divergence during the evolutionary process. Here, the crystallization and high-resolution X-ray diffraction analysis of a human tRNA(Gly) acceptor-stem microhelix with sequence 5'-G(1)C(2)A(3)U(4)U(5)G(6)G(7)-3', 5'-C(66)C(67)A(68)A(69)U(70)G(71)C(72)-3' is reported. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 37.32, b = 37.61, c = 30.47 A, beta = 112.60 degrees and one molecule per asymmetric unit. A data set was collected using synchrotron radiation and data were processed within the resolution range 50.0-1.18 A. The structure was solved by molecular replacement.