Fig. 6: Structure of nucleotide-free and KDL bound to MsbA in an open, outward-facing conformation.

a The 2.7 Å cryoEM density map colored by subunit. The density for KDL is colored purple. b View of KDL bound to the exterior site shown in stick representation. c, d Different views of the NBDs shown in cartoon representation. The vanadate-trapped MsbA structure (PDB 8DMM) is aligned to one chain and colored light blue. The ADP and vanadate bound in PDB 8DMM are shown in stick representation. e Key interactions stabilizing the NBD interface. Conserved NBD motifs are shown with the A-loop in salmon, Walker A (P-loop) in purple-blue, Q-loop in marine, X-loop in light pink, C-loop in cyan, Walker B in bright orange, D-loop in red, and the H-switch in yellow. f The π–π interaction observed in nucleotide-bound structures is substituted by a cation-π interaction.