Figure 1.

The HlyIIR structure. (a) Electron density corresponding to one of the protein helices (α1) calculated with maximum likelihood weighted coefficients 2|F_o|–|F_c| and contoured at 1.25σ. (b) and (c) Ribbon diagrams of HlyIIR. Monomer (b) is rainbow-coloured with its N-terminal in red and C-terminal in blue. Dotted line indicates the disordered segment, which was not modelled. The biological dimer (c) is generated by the crystallographic 2-fold axis. The large internal cavity (yellow) is drawn along the van der Waals radii of cavity-forming residues. The cavity surface was calculated by SURFNET.³³ This Figure and Figures 3 and 4 were prepared using CCP4MG.³⁴