Figure 3.

Stereoview showing the binding of buffer molecules in the active site of FlvF. (a) Polder omit maps corresponding to Bis-Tris molecules bound in Chain B are shown as dark blue mesh and contoured at 4.5σ. Black dashed lines represent atomic distances between 2.8 – 3.6 Å and likely indicate hydrogen bonds, taking into account the structure coordinate error of 0.37 Å. (b) Overlay of Bis-Tris binding sites in Chains A, B, and D. Selected side chains are shown for Chain B. Atoms are color-coded as follows: C = blue (FlvF), yellow (Bis-Tris), N = blue, O = red.