Fig. 3.

Cartoon representation of the C₄ PEPC enzyme structure of Flaveria trinervia (ppc-2 gene) (Paulus et al., 2013), showing the location of functional residues in comparison with sites that were identified to be under positive selection in Suaedoideae. Green residues are sites under positive selection, biochemically essential residues are in a shade of red (histone 177 is bright red, Mg²⁺-binding sites are ruby, PEP- and HCO₃ ^–-binding sites are dark red, Lys606 is brown), allosteric regulatory sites are in a shade of blue (deep-blue residues are glucose 6-phosphate-binding sites, light blue are malate/aspartate-binding sites), Gly890 is orange, and Ser780 is yellow (maize numbering). Residue 733 is indicated with a white arrow. The proposed residue function is adapted from Kai et al. (2003).