Phylogenetic relationship between Dml/TDHs, IPMDHs, and IDHs. The unrooted phylogenetic tree shows the evolutionary relationship between IPMDHs (green), NAD-dependent IDHs (pink), and Dml/TDH/TtuC enzymes (Dml/TDHs are blue, and TtuC enzymes are cyan) from α-, β-, and γ-Proteobacteria. The protein names are indicated for those proteins that have been characterized in vivo and/or in vitro (28, 51, 55, 56, 66). The other proteins are designed with an ID number referring to the complete data set presented in the supplemental material.