Figure 2
Pae87 structure. (a) Superimposition of the catalytic domains of Pae87 (cyan, PDB entry 7q4t) on AP3gp15 (magenta, PDB entry 5nm7), with the AP3gp15 CWBD shown in orange. The putative catalytic residues Glu29 and Glu46 from Pae87 and Glu101 and Glu118 from AP3g015 are shown in stick representation. (b) Ribbon representation of the apo Pae87 model coloured green (PDB entry 7q4s). A CHES molecule is depicted as orange sticks and is flanked by the putative catalytic amino acids (Glu29 and Glu46) and several aromatic residues in stick representation. A triethylene glycol fragment molecule (orange sticks) is present at the back of the protein, in the same place as the peptidoglycan in (e). (c) Side view (top) and top view (bottom) of the Pae87 protein model in ribbon representation (cyan). The peptidoglycan molecule is shown as violet sticks. (d) Close-up view of the active site depicted as in (b). The CHES molecule is represented with its 2Fo − Fc electron-density map contoured at 1σ (grey). (e) View of the peptidoglycan fragment depicted as in (b) with its 2Fo − Fc electron-density map contoured at 1σ (grey), the binding amino acids (cyan, stick representation) and the water molecules (red spheres) taking part in the hydrogen-bond network (yellow dashed lines). (f) Schematic representation in Fischer projection of the peptidoglycan fragment bound to Pae87. (g, h, i) Close-up views of the peptidoglycan fragment components (D-Gly and L-Ala, MurNAc and NAG, respectively) depicted as in (c). |