Figure 1.

(a) Structure of Mtb DsbF in its oxidized form is shown as a ribbon diagram. The β-sheets, α-helices and random coil are colored blue, red and cream, respectively. The atoms for the two active-site cysteines, Cys81 and Cys84 are colored in yellow. (b) and (c) Electron density surrounding the active-site CxxC motif of Mtb DsbF where the cysteines are modeled in both the (b) oxidized and (c) reduced forms. The 2fo-fc electron density mesh (blue) and the fo-fc negative density mesh (red) are contoured at sigma 3.0. Shown are stick cartoons of the active-site where the carbon, oxygen, nitrogen and sulfur atoms are colored in white, red, blue and yellow, respectively.