Figure 6. AMP–PNP binding to the EcfAA′ heterodimer.
(a) Surface representation AMP–PNP-bound EcfAA′ heterodimer coloured as in Fig. 3 with the AMP–PNP molecules in stick representation. The viewpoint is from the extracytoplasmic side (b) Cartoon representation of the AMP–PNP-bound EcfAA′ heterodimer and the coupling helices CH2 and CH3 of EcfT. The conserved arginines at the C-terminal end of the coupling helices, and the interacting aspartates in the EcfAA′ heterodimer are shown in sticks. The interactions are indicated by the dashed lines. (c) AMP–PNP-binding site on EcfA′ (coloured light red). The conserved motifs found in ABC transporter ATPases are indicated. (d) 2Fo–Fc electron density at 2σ in blue contouring AMP–PNP (same viewpoint as in c).