Fo − Fc randomized omit map for bound aminoglycoside and donor moiety (S–H or S–COCH3) of CoA contoured at 2.5σ for the (A) KANC/(AcCoA), (B) RIB/(CoA), and (C) PAR/(AcCoA) complexes. Prior to calculation of the electron density map temperature factors were set to 20 Å2, random errors were added to the coordinates to yield an rmsd of 0.25 Å to the parent structure, the ligands were removed, and the resulting structure was refined for 10 cycles in REFMAC. (D) Superposition of the KANC/AcCoA, RIB/CoA, and PAR/AcCoA complexes with AAC(6′)-Ib. Molecular surface and ribbon diagram of AAC(6′)-Ib are shown in gray and black, respectively. (E) Electrostatic potential of AAC(6′)-Ib mapped on the molecular surface contoured at ±5 kT (red, negative; blue, positive). PAR and AcCoA shown as sticks and colored with blue and yellow carbons, respectively.