1. Structures of four importers.
Structures of four importers. All transporters consist of four subunits, including a homodimer or heterodimer of IM subunits and a homodimer of NBD subunits. The ModB2C2 transporter is cocrystallized with ModA, a periplasmic BP in a closed, liganded conformation (cyan). The ligand, molybdate, is represented with a space-filling model. Maltose-BP (purple) is trapped in complex with MalFGK2 by using an E159Q substitution in MalK to prevent ATP hydrolysis (343). Nucleotide (ATP) is present only in MalFGK2E. A space-filling rendition of MalFGK2 is cut away to reveal an occluded pocket containing bound maltose. (Lower panel modified from reference 343.)‏
Amy L. Davidson et al. Microbiol. Mol. Biol. Rev. 2008; doi: /MMBR