Ramachandran structure viewer

Each point is one amino acid residue in a coordinate model. φ and ψ are calculated from its backbone atoms and its neighbours. The examples contain real structures from RCSB PDB; this tool does not simulate protein folding.

Use

Choose an example or open an uncompressed PDB/mmCIF file (maximum 20 MB). Analysis runs locally in a worker with progress and cancellation. Choose a chain and residue class. Click a point or use the residue selector to read its identity and angles. CSV exports the current selection. Uploaded contents are neither sent to a server nor saved in browser storage.

References

The background comes from Richardson Lab Top8000 percentile grids, not invented shapes. Dark and light areas use levels 0.02 and 0.002 (98% and 99.8% contours). The original 2° cells are preserved. These uniform display levels are not the class-specific MolProbity validation thresholds, and the tool does not label points as valid or outliers. No background is displayed for mixed classes.

Geometry and limits

Only the first coordinate model is analysed. Standard amino acids, MSE, SEC and PYL are supported. A coherent backbone alternate conformation with the highest summed occupancy is selected; shared atoms can be used. Missing or zero-occupancy atoms, chain breaks, terminal residues and degenerate angles are omitted. Peptide C–N distances must be 0.8–1.8 Å. Proline classes use the preceding ω angle (cis if |ω| < 90°). Pre-proline means the residue immediately before proline, excluding glycine and proline. Isoleucine and valine have a separate reference. A point outside the contours alone does not establish an incorrect structure.

Reference: Williams et al. (2018), MolProbity. Data: Richardson Lab, Duke University, CC BY 4.0. This is an independent viewer, not a full MolProbity validation report.