(A) The reaction catalyzed by ODCase. (B) The physiological dimer of MtODCase. The green arrows indicate the binding positions of the ligands, which are drawn as green spheres. (C) The electrostatic and hydrogen bond network in the active site of ODCase. WT-MtODCase complexed with BMP (PDB: 1x1z) is presented as an example. (D) The substrate analogues described in this paper. Atom names are in blue. 1: 6-methyl-UMP, 2: 6-amino-UMP, 3: BMP, 4: OMP-methyl-ester, 5: OMP-ethyl-ester