Figure 1.

Primary sequence of DsbB showing characteristic features. The essential cysteines are shown in red and methionines are in green. The two positions shown by solid black circles are cysteines in the wild-type sequence. The segment constituting the horizontal α-helix is shown in orange. Regions that lack corresponding electron density in the solved crystal structure of DsbB(Cys41Ser) are shown in grey. The sites where SeMet was introduced to model the horizontal helix and the following loop are indicated by arrows that specify the substitutions.