Backbone Brackets and Arginine Tweezers delineate Class I and Class II aminoacyl tRNA synthetases
Fig 2
The Rodin-Ohno hypothesis states that both aaRS classes descended from the opposite strands of a single gene.
The signature motifs of each class were fully complementary on this gene. Both Protozymes originated from the complementary “HIGH-Motif 2” region (shaded in red). Contemporary aaRS feature insertion domains (ID) and Connecting Peptides (CP1) as well as the addition of the anticodon binding domain (ABD). Figure adapted from [9, 67].