Structural comparison of the active sites of the two H. volcanii complexes. SSM overlay as in figure 10, but showing detail in the region of the active site. The side chain of Val 191 has been omitted for clarity. a) Top view, roughly perpendicular to the glyoxylate molecule. Carbon atoms, magnesium ions, hydrogen and metal-ligand bonds are colored yellow or green in the glyoxylate or ternary complex respectively. Water molecules are depicted as spheres colored red in the glyoxylate and lilac in the ternary complex. Close contacts to the pyruvate methyl group are shown as red dashed lines with distances in angstroms. b) Side view of part a in stereo. Additionally, the close contact between the acetyl methyl carbon of acetyl-CoA and the ketone carbonyl carbon in pyruvate, and the distances between this methyl carbon and the side chain carboxylate oxygens of Asp 388 are shown in red and grey dashed lines respectively.