FIGURE 6.
Substrate 3-MC interaction in the crystal structure of AkbC. A, electron density maps for 3-MC found in the active sites of molecule B (left) and D (right). The 2Fo−Fc (blue) and Fo−Fc (red) electron density maps were contoured at the 1.5 and 3.0 σ level, respectively. B, 3-MC in molecule B is sandwiched between His-244 and Phe-189. It is bound to the iron, a water molecule, Asn-246 and Asp-247, and in close contact with Tyr-175. C, two 3-MC-bound structures are compared. Molecules B (green) and D (cyan) are superimposed. Residues surrounding 3-MCs including those from the β-hairpin structure, and the C-terminal tail are shown as sticks. The iron and water molecule are shown as brown and red spheres, respectively. The distances between interacting atoms are indicated.