Figure 2.

Comparison of the apo and metal bound structures of CusA. (a) Superimposition of a monomer of apo-CusA (magenta) onto a monomer of Cu(I) bound-CusA (yellow). The bound Cu(I) is in blue. The arrow represents a major swing of the PC2 sub-domain initiated by Cu(I) binding. (b) Conformational changes of the periplasmic domain of CusA. The conformation of each sub-domain of CusA before (left) and after (right) Cu(I) binding. The periplasmic cleft formed between PC1 and PC2 is opened after Cu(I) binding. The bound coppers in the CusA–Cu(I) structure are coloured blue. M573, M623 and M672 forming a metal binding site at the periplasmic cleft are shown in stick form (magenta). (c) The changes in conformation of the horizontal helix and TM8, are shown in a superimposition of the structures of apo (magenta) and Cu(I)-bound (yellow) CusA. The bound Cu(I) is shown as a blue sphere. Anomalous map of the bound Cu(I), contoured at 8σ, is in green. M573, M623 and M672 are shown as sticks. (d) The Ag(I) binding site. The bound Ag(I) is shown as a grey sphere. Anomalous map of the bound Ag(I), contoured at 10σ, is in red.