Figure 1
Event map generated by PanDDA around Tyr110 and fragments 1 and 2. (a) Architecture of the apo BpsDsbA structure (PDB entry 4k2d; Ireland et al., 2014) represented as a cartoon. α-Helices and β-strands are numbered α1–α7 and β1–β5, respectively. The active-site cysteines are indicated by yellow spheres; Tyr110 is represented in blue in stick format. (b) Close-up of the orientation of Tyr110 in the apo structure (no ligand present) and (c) and (d) in the presence of 1 and 2, respectively. The Tyr110 side chain rotates to the right in this orientation (viewed along the Cβ—Cγ bond) towards helix α3 compared with the apo structure. This shift opens a small hydrophobic pocket into which the fragment binds. The reference apo 2mFo − DFc map, contoured at 1 r.m.s.d. and shown in orange, is the result of averaging 32 electron-density maps of apo BpsDsbA. The PanDDA event maps are shown in blue and are contoured at 2 r.m.s.d. for 1 and 2 in (c) and (d), respectively. These maps are estimates of the ligand-bound state (Pearce, Krojer, Bradley et al., 2017). The background density correction (BDC) and the resolution (Res) are given for the event maps in (c) and (d). |