Figure 5.

Importance of the cofactor Mg²⁺ in monomer–monomer interactions in the H662A dimer of HlyB. (A) Symmetric and (B) asymmetric interactions between the monomers of the ATP- (left panel) and ATP/Mg²⁺- (right panel) bound complexes of the HlyB-NBD H662A. Color-coding is identical to Figure 1. Solid lines represent hydrogen bonds (distance cutoff of 3.2 Å) and dashed line van der Waals interactions (distance cutoff of 4.0 Å). Light blue spheres represent water molecules. Letters indicate the atoms involved in the interactions.