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Figure 4
The active site of the Ldt domain and the substrate-binding sites. (a) Active-site superposition of the apo (orange), mercury-derivatized (magenta) and meropenem-complexed (chain B, cyan) LdtMt2Δ130. Dotted lines denote interactions: hydrogen bonds to the catalytic triad (red) and the oxyanion hole (green), Ser351 with the oxyanion hole (black), His336 with Asn356 (black) and His352 with Cys354 Sγ and the main-chain carbonyl O atom of His352 in the mercury-derivatized model (purple). The covalently bound meropenem adduct in the meropenem complex is shown as a stick model. (b) Active-site superposition of meropenem-complexed LdtMt2 (chain B, cyan), LdtBs (green) and Ldtfm (grey) in the same view as in (a). (c, d) Electrostatic surface representations of the predicted binding sites for the donor substrate in the open conformation of mercury-derivatized LdtMt2Δ130 (c) and the acceptor substrate in the closed conformation of meropenem-complexed LdtMt2Δ130 (d) coloured as in Fig. 1 ![]() |