fig2

Figure 2. Cathepsin K (A) with co-crystalized and cathepsin B (B) with superimposed myochrysine (Au-thiomalate) are represented in mesh surface and colored ribbon style. Au atom is shown as a blue sphere. A secondary structure color scheme (suggests different colors for different secondary structures) was used for ribbon representation. A schematic representation of ligand binding mode and the geometry of the Au atom and the sulfur bridge in cathepsins K (C) and B (D). Ionic bond length and angle between the terminal sulfur of Cys25 of cathepsin K are indicated. The same view of CF₃-substituted triethylphosphine in the active site of cathepsin B with mutated Cys29 to Ala29 is shown in (D)