Structural comparison of the VcINDY, MtrF, and YdaH transporters. (A) A structural alignment of the whole structure of each protomer is shown from the extracellular side of the membrane, with the helices colored according to the topology. The MtrF-VcINDY, YdaH-VcINDY, and MtrF-YdaH alignments are shown on the left, middle, and right, respectively. The structural superimpositions of the scaffold-oligomerization (B) and transport (C) domain are shown from a view parallel to the membrane plane. The scaffold-oligomerization domains exhibit the most significant differences, which are highlighted in red. The structural alignments were obtained using the program Fr-TM-align. The RMSD and TM-score of the structural alignment are given in each case, along with the number of aligned residues and the length of the shortest input.