2.A.68.1.4
YdaH transporter of 492 aas with p-aminobenzoyl-glutamate uptake activity.  The crystal structure is known (Bolla et al. 2015). The crystal structure reveals a dimeric molecule with an architecture distinct from other families of transporters. YdaH is a bowl-shaped dimer with a solvent-filled basin extending from the cytoplasm to halfway across the membrane bilayer. Each subunit of the transporter contains nine transmembrane helices and two hairpins that suggest a  pathway for substrate transport. YdaH could act as an antibiotic efflux pump and mediate bacterial resistance to sulfonamide antimetabolite drugs (Bolla et al. 2015).  MtrF (TC#2.A.68.1.2) and YdaH as well as the dicarboxylate transporter, INDY (TC#2.a.47.5.2) have been shown to have similar 3-d folds (Vergara-Jaque et al. 2015), confirming the assignment of these two families to the same superfamily (Prakash et al. 2003).