Figure 8
Structure of BpsDsbA crystallized with 2 (PDB entry 7luj). (a) Overall representation of the four molecules of BpsDsbA in the asymmetric unit. There are three copies of fragment 2. Two copies bind near Tyr110 of chains A (cyan) and B (beige); they are partially overlapping and almost perfectly rotamerically symmetric around a C2 axis. The third copy of the ligand binds near Tyr110 of chain D (purple). No fragment was found in chain C (forest green). The position of the ligands are highlighted by red circles. The active-site S atoms are represented as spheres, and the protein chains are shown as cartoons with α-helices represented as cylinders for simplicity. (b, c) 2mFo − DFc electron densities at 2.31 Å resolution (contoured at 0.8 r.m.s.d., blue) around chain D. (b) The map around the loop between residue Pro29 and Lys32 (highlighted in grey) was not particularly sharp; single residues were difficult to fit in the densities and the electron density is discontinuous between Ala30 and Gly31. (c) Similarly, electron density was absent for the side chain of Tyr110 (note that fragment 2 was removed from this image for clarity). |