$npx -y skills add GPTomics/bioSkills --skill conformer-generationGenerates 3D conformer ensembles using RDKit ETKDGv3 with knowledge-enhanced distance geometry, MMFF94/UFF force-field optimization, CREST + GFN2-xTB semi-empirical refinement, and macrocycle-aware torsion preferences. Provides explicit decision rules for single vs ensemble confo
| 1 | ## Version Compatibility |
| 2 | |
| 3 | Reference examples tested with: RDKit 2024.09+, xtb 6.7+, CREST 3.0+, OpenMM 8.1+ for follow-up MD. |
| 4 | |
| 5 | Before using code patterns, verify installed versions match. If versions differ: |
| 6 | - Python: `pip show <package>` then `help(module.function)` to check signatures |
| 7 | - CLI: `xtb --version`; `crest --version` |
| 8 | |
| 9 | If code throws ImportError, AttributeError, or TypeError, introspect the installed |
| 10 | package and adapt the example to match the actual API rather than retrying. |
| 11 | |
| 12 | # Conformer Generation |
| 13 | |
| 14 | Generate 3D conformer ensembles for molecules from 2D structures. The choice of method depends on molecule size, flexibility, and downstream use: ETKDG (Riniker & Landrum 2015) and its ETKDGv3 macrocycle update (Wang et al. 2020) are modern defaults for drug-like molecules, MMFF94/UFF provide fast energy minimization, and CREST + GFN2-xTB provide higher-cost semi-empirical sampling. A single conformer may be insufficient when the downstream result is conformation-sensitive; determine ensemble size by convergence of the downstream descriptor, alignment, or docking result. |
| 15 | |
| 16 | For docking pose validation, see `chemoinformatics/pose-validation`. For free-energy methods (which require ensemble sampling), see `chemoinformatics/free-energy-calculations`. |
| 17 | |
| 18 | ## Conformer Method Taxonomy |
| 19 | |
| 20 | | Method | Cost / mol | Quality | Use case | Fails when | |
| 21 | |--------|-----------|---------|----------|------------| |
| 22 | | ETKDGv3 + MMFF94 | Benchmark on actual molecules/hardware | Useful for many drug-like organics | Initial docking/descriptors | Difficult macrocycles, peptides, unsupported chemistry | |
| 23 | | ETKDGv3 + UFF | Fast | Different parameter coverage from MMFF94 | Fallback only after checking UFF parameters | Unsupported atom types; coordination chemistry | |
| 24 | | Omega (OpenEye) | Benchmark licensed workflow | Commercial conformer generator | Commercial pipelines | License cost and configured limits | |
| 25 | | Confab (Open Babel) | Benchmark on intended chemistry | Systematic torsion search | Alternative enumeration | Combinatorial growth and force-field dependence | |
| 26 | | RDKit ETKDGv3 + macrocycle preferences | Molecule-dependent | Macrocycle-aware embedding | Macrocyclic starting ensembles | Coverage remains molecule-dependent | |
| 27 | | CREST + GFN2-xTB | Molecule/settings-dependent | Semiempirical conformational sampling | Difficult flexible molecules | Computational cost; special chemistry | |
| 28 | | CREST + GFN-FF | Lower cost than GFN2-xTB | Force-field-level sampling | Exploratory sampling | Validate coverage and ordering for the chemistry | |
| 29 | | GeoMol (Ganea 2021) | Hardware/model-dependent | Learned conformer generation | Large-library research workflow | Training distribution and released-model coverage | |
| 30 | | TorsionNet (Gogineni 2020) | Hardware/model-dependent | Learned torsional search | Research workflow | Training distribution and implementation availability | |
| 31 | | MD sampling (OpenMM) | System/protocol-dependent | Dynamic sampling | Free energy, induced fit | Computational cost and convergence | |
| 32 | |
| 33 | **Decision:** Start drug-like organic molecules with **ETKDGv3** and a parameter-checked MMFF94/MMFF94s optimization. Escalate difficult macrocycles, peptides, or highly flexible molecules to a validated CREST workflow when downstream convergence is inadequate. Benchmark ML generators on the intended chemistry before using them at scale. |
| 34 | |
| 35 | ## Decision Tree by Scenario |
| 36 | |
| 37 | | Scenario | Starting method | Sampling and filtering decision | |
| 38 | |----------|-----------------|---------------------------------| |
| 39 | | Single initial 3D structure | ETKDGv3 + checked force field | Confirm embedding and minimization; downstream relaxation may still be required | |
| 40 | | Multi-conformer docking | ETKDGv3 ensemble | Increase sampling until pose recovery or enrichment is stable | |
| 41 | | 3D descriptors / pharmacophores | ETKDGv3 ensemble | Converge the reported statistic; justify energy/RMSD filters | |
| 42 | | Macrocycle / peptide | Macrocycle-aware ETKDG, then CREST if needed | Compare coverage against known conformers or downstream convergence | |
| 43 | | FEP input | Bound-pose-informed preparation and MD | Do not select solely by isolated-molecule conformer energy | |
| 44 | | Shape search | Query- and library-specific ensemble | Converge retrieval performance on a reference set | |
| 45 | |
| 46 | ## ETKDGv3 (Modern Default) |
| 47 | |
| 48 | ETKDGv3 (Wang et al. 2020), building on the original ETKDG method (Riniker & Landrum 2015), incorporates experimental torsio |