Figure 7.
YiuA conformational changes. Structural differences between the crystal forms suggest that the carboxy-terminal lobe is a flexible lobe. (a) Cartoon representation of structure superimposition of YiuA crystal forms 1 and 2. Models are colored by r.m.s.d. Blue indicates good alignment, with moderate deviations in purple and higher deviations in red. White indicates residues that were not used in alignment. The highest deviations are seen in helices 5 and 10 at the bases of the lobes. (b) Solvent-exposed surface dots representation of the crystal form 1 base colored by outer shell (gray), cavity (orange) and site 1 pocket (yellow). Measurements of the solvent-exposed surface area are as follows: total, 14 481 Å2; cavity, 2682 Å2; site 1 pocket, 224 Å2. (c) Solvent-exposed surface dots representation of the crystal form 2 base colored by outer shell (gray), cavity (purple) and site 1 pocket (yellow). Measurements of the solvent-exposed surface area are as follows: total, 14 810 Å2; cavity, 2819 Å2; site 1 pocket, 332 Å2. (d, e) Structure comparison of crystal form 1 molecule A and crystal form 2 molecule B validates the conformational changes. Crystal form 1 model (orange) overlaid with 2F o − F c electron difference density (bright blue mesh) and crystal form 2 model (purple) overlaid with 2F o − F c electron difference density (light green mesh) show regions of structural identity and regions of structural differences.