Abstract
The major dissimilarities between the eukaryotic/archaebacterial-type and eubacterial-type glycyl-tRNA synthetase systems (GlyRS; class II aminoacyl-tRNA synthetases) represent an intriguing example of evolutionarily divergent solutions to similar biological functions. The differences in the identity elements of the respective tRNA(Gly) systems are located within the acceptor stem and include the discriminator base U73. In the present work, the human tRNA(Gly) acceptor-stem microhelix was crystallized in an attempt to analyze the structural features that govern the correct recognition of tRNA(Gly) by the eukaryotic/archaebacterial-type glycyl-tRNA synthetase. The crystals of the human tRNA(Gly) acceptor-stem helix belong to the monoclinic space group C2, with unit-cell parameters a = 37.12, b = 37.49, c = 30.38 A, alpha = gamma = 90, beta = 113.02 degrees, and contain one molecule per asymmetric unit. A high-resolution data set was acquired using synchrotron radiation and the data were processed to 1.2 A resolution.