Conformational behavior
of the carbapenem 6α-hydroxyethyl
group. Left: 6α-Hydroxyethyl group can assume three different
orientations, which can be distinguished by the C7–C6–C–O
dihedral angle values. When the dihedral is around 50° (orientation
I), the hydroxyl group is hydrogen bonded with the DW, and in the
180° orientation (II), the hydroxyl group can only interact with
the solvent. In the 290° orientation (III), the hydroxyl group
donates a hydrogen bond to the carboxylated Lys73. Right: Distribution
of sampled dihedral values during MM MD simulations of the IME and
MER ACs (5 × 150 ns per carbapenem).