Crystal structure of a human tRNAGly microhelix at 1.2 Å resolution

The tRNAGly/glycyl-tRNA synthetase (GlyRS) system belongs to the so-called ‘class II aminoacyl-tRNA synthetase system’ in which tRNA identity elements are assured by rather few and simple determinants mostly located in the tRNA acceptor stem. Regarding evolutionary aspects, the tRNAGly/GlyRS system is a special case. There exist two different types of GlyRS, namely an archaebacterial/human type and a eubacterial type reflecting an evolutionary divergence within this system.Here we report the crystal structure of a human tRNAGly acceptor stem microhelix at 1.2 Å resolution. The local geometric parameters of the microhelix and the water network surrounding the RNA are presented. The structure complements the previously published Escherichia coli tRNAGly aminoacyl stem structure.