Backbone Brackets and Arginine Tweezers delineate Class I and Class II aminoacyl tRNA synthetases
Fig 7
Integrative sequence view for aaRS Class I (A) and Class II (B).
Boxes delineate sequence motifs previously described in literature [46, 57, 58]. The trace depicts the sequence conservation score of each position in the MSA (S5 and S6 Files). These scores were computed with Jalview [40, 87], positions composed of sets of amino acids with similar characteristics result in high values. Furthermore, all positions relevant for ligand binding (Fig 5) are depicted. Backbone Brackets and Arginine Tweezers have been emphasized by their respective pictograms. Positions of low conservation or those not encompassed by sequence motifs were intangible to studies primarily based on sequence data. Especially backbone interactions might be conserved independently from sequence. (C) Sequence representation of the Rodin-Ohno hypothesis [8, 9, 11] with equivalents of the Backbone Brackets or Arginine Tweezers residues shown as green dots. The N-terminal residue of each, the Backbone Brackets and the Arginine Tweezers motif, is present in the Protozyme region (shaded red). Additionally, the C-terminal Backbone Brackets residue is located in the Urzyme region.