Backbone Brackets and Arginine Tweezers delineate Class I and Class II aminoacyl tRNA synthetases
Fig 6
Geometric analysis of the ligand recognition motifs responsible for the adenosine phosphate interaction for aaRS Class I and Class II representative and nonredundant structures.
The alpha carbon distance is plotted against the side chain angle θ. Binding modes refer to states containing an adenosine phosphate ligand (M1) or not (M2). Backbone Brackets in M1 allow for minor variance with respect to their alpha carbon distance, constrained by the position of the bound ligand. In contrast, Arginine Tweezers in M1 adapt an orthogonal orientation in order to fixate the ligand.