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![[Figure 1]](qe5002fig1mag.jpg)
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Figure 1
FLEXR workflow. FLEXR builds multi-conformer models based on electron-density sampling around side-chain dihedrals (χ) performed by Ringer. (a) FLEXR detects peaks in the electron-density measurements above a user-defined σ threshold (default 0.3σ). Peak angles from each dihedral are assembled into possible rotamers and checked against the ideal rotamer library (Lovell et al., 2000  ). Valid alternate conformers are automatically built using Coot. Refining the multi-conformer models estimates occupancies and improves the geometry. (b) An example of the workflow is shown for Met313 in prostaglandin reductase 3 (MGC45594), which is modeled in a single conformation in the A chain of the 1.45 Å resolution structure (PDB entry 2c0c). Top: two peaks (stars) are detected in electron density sampled around χ3 using data > 0.3σ (red dashed line). Bottom: combining the detected peaks across the three dihedrals yields two possible rotamers. (c) After automated building with Coot, a visual inspection shows that the two rotamers (green sticks) satisfy the deposited electron density. A final refinement with Phenix shows that the two rotamers have roughly equal occupancies. The deposited 2mFo − DFc map (blue) is contoured at 1σ and the mFo − DFc difference density map (green) is contoured at 3σ. |
![[Figure 1]](qe5002fig1.jpg)
 | STRUCTURAL BIOLOGY |
ISSN: 2059-7983
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