PROTEIN EVIDENCE EXPLORER
Explore a structure.
Inspect the contacts.
Rotate a published human carbonic anhydrase I structure and inspect its bound ligand: acetazolamide or methazolamide.
Drag to rotate. Green trace: protein Cα backbone. Ligand atoms: carbon grey, nitrogen blue, oxygen red, sulfur gold. Zinc: purple. Dashed lines: selected nearest-atom distances, not inferred chemical bonds. Grey points: nearby protein atoms.
What does “attach” mean here?
These structures show a ligand present in an experimentally determined protein complex. Proximity is useful evidence to inspect, but a distance cutoff alone does not prove a particular interaction or predict whether a new molecule will bind.
Comparing the two deposited complexes is not an affinity ranking. Testing new candidates requires a separately validated modelling or experimental workflow.
Method and reproducibility
Public PDB entries 1AZM and 1BZM; human carbonic anhydrase I, X-ray diffraction, reported resolution 2.0 Å. Only chain A and blank/A alternate locations are shown. Water and hydrogen atoms are excluded from contact calculations. The interface displays a Cα trace rather than a full secondary-structure model. Ligand bonds use deposited CONECT records; they do not encode bond order in this view.
For each protein residue, the app calculates the minimum Euclidean heavy-atom distance to a ligand atom, in ångströms. The report includes the cutoff, atom-pair identifiers, coordinates, source metadata and a SHA-256 checksum of the original PDB file. Crystal packing, missing atoms, alternate conformations and solvent-mediated interactions can affect interpretation. Zinc distances are shown separately from protein residues.
Primary structural reference: Chakravarty and Kannan, refined structures of sulfonamide complexes of human carbonic anhydrase I. Follow the deposited records for full citation and validation information. Public coordinates retrieved 30 October 2026. Independent portfolio implementation built with AI assistance.