Fig. 2. Crystallographic evidence for conformational changes in SPM-1. (A) Comparison of SPM-1 structures with the α3 region in an ‘open’ (PDB ID: 2FHX) and ‘closed’ (PDB ID: ; 4BP0) conformation. (B) Representative 2Fo–Fc electron density contoured to 1σ (blue mesh) of the active site residues and Zn atoms for the ‘closed’ SPM-1 structure. (C) Superimposition of CphA (purple, PDB ID: ; 1X8I) and the ‘closed’ SPM-1 structure (green), showing the position of hydrolysed biapenem in the active site.
