CAPS 2.0 analysis of coevolving sites in plant AGOs. (A) shows heatmaps of coevolving sites in the four classes of plant AGOs. Coevolving pairs showing correlation coefficient of ≥0.5 are plotted. (B) is the color-coded representation of the coevolution frequency matrix of 20 amino acid pairs in NaAGO1a, NaAGO5, NaAGO2 and NaAGO4a, the representatives of four classes respectively. (C) Threaded structures of NaAGO1a, NaAGO5, NaAGO2 and NaAGO4a show the position and arrangement of top coevolving groups in the classes I-IV respectively (orange, green and blue colored; residues in black represent other functionally important coevolving sites as described in Results and Discussion). Residues coded with same color show the correlation with each other in evolutionary context.