Fig. 6
From: The molecular basis of phosphite and hypophosphite recognition by ABC-transporters
The volume of the binding pocket in Pm_PtxB is ~25% bigger than that of Te_PtxB and Pm_PhnD. Superposition of the Pm_PtxB/phosphite structure (pink) with those of Te_PtxB (grey) and Pm_PhnD (blue) (a) shows how a sequence difference (black arrow) in the binding pocket increases the volume of the cavity in Pm_PtxB. In Te_PtxB (b) and Pm_PhnD (c) Leu20 and Ile11 (respectively) provide a hydrophobic surface for the ligand to pack against within the binding pocket. In Pm_PtxB (d) Ile20 adopts an alternative rotamer making the hydrophobic region of the pocket slightly larger, as indicated by the asterisk (*)
