Position II, the dominant position in the wild type enzyme (~66% of the simulation time), is only present for about 2.5% of the time in simulations of the mutant enzyme. This is due to the loss of the hydrogen bond between Asn132-ND2 and the hydroxyl moiety of the 6α-1R-hydroxyethyl group. For the BlaC Gly132Asn mutant, the dihedral in Position II is observed for a considerable amount of simulation time (about the same time as for Position III (Figure ), whereas this orientation was not observed in the wild type acyl-enzyme. In simulations of TEM-1, while Position I dominates the conformational distribution for the wild-type enzyme, the Asn132Gly mutant is able to sample all three positions during 3 ns of MD simulation of the meropenem acylenzyme. In Position II, however, the methyl of the 6α-1R-hydroxyethyl group displaces the DW from the active site (as also observed for CTX-M-16, see above), and this trajectory can thus be considered as inactive.