Figure 3

Tertiary structure models of Hmd enzymes and paralogs superimposed onto a phylogenetic tree. Models labeled "R" represent the model with the best RAPDF score [30] for a given protein. Models labeled "C" represent the model with the best C-score [27] for a given protein. Models labeled "RC" had both the best RAPDF and C-score for a given protein. Features of these models are summarized in Table 1. All models contain the same overall structure consisting of an N-terminal domain composed of α-helices and β-sheets and a C-terminal domain composed of α-helices. In the Hmd enzyme, the N-terminal domain contains the catalytic site while the C-terminal domain facilitates dimerization in the Hmd holoenzyme. In general, the N-terminal domain exhibits more structural variability than the C-terminal domain (see Table 1).