Opsin snake plot (a) and 3D model (b) showing sites inferred to be evolving under divergent selection pressure according to Bayes empirical Bayes analysis with the CmC αβ
Clade model. Only sites with PP > 0.75 are shown. (a) The seven transmembrane α helixes (TM1-TM7), helix 8 (H8), and the extracellular (E1-E3) and cytoplasmic (C1-C3) loops are labeled. Every 10th amino acid (starting with AA 10) is shaded grey and drawn in thicker stroke. (b) The opsin backbone is shown as a gray ribbon, while the retinal chromophore is shown in black stick format. The 3D model is viewed with the extracellular side on top. For both (a) and (b) the protein structure and numbering follow bovine rhodopsin.