Figure 5 - full size

Figure 5.
Figure 5. AhpE surface in the vicinity of the active site. (a) The oxidized AhpE structure, in which Cys45 forms a sulfenic acid, Arg116 is directed away, and a large surface channel approaches the active site. (b) Reduced AhpE, seen in molecule B of the bromide-soaked structure, with Arg116 directed towards Cys45 Sg, and no surface channel except for a deep, positively charged cavity leading to Cys45.