ligsite — protein–ligand interaction diagrams

Drop a PDB or mmCIF file (Boltz output works directly). The structure is parsed, the ligand depicted in clean 2D matched to its bound conformation, and the binding-site residues drawn around it. Everything runs in this tab — the file is never uploaded, because there is nowhere to upload it to.

starting…

Structure

Drop a .cif or .pdb here
or click to choose

This is the only outbound request the page ever makes, and only when you ask for it: the entry is downloaded from RCSB (or PDBe) straight into this tab. Files you drop are still never transmitted anywhere.

Diagram

A ceiling on every distance drawn. Each type also keeps its own limit (H-bond 3.6, salt 4.5, π-stacking 5.6, π-cation 6.0 Å), so raising this past one of those adds no more of that type. π and salt distances are measured between centroids, not nearest atoms, so they read larger than an atom contact for the same residue pair.

0 = a clean textbook depiction. 1 = torsions follow the bound pose as closely as rigid 2D geometry allows.

0 — each label sits against what it touches, no ring. 1 — a clean ring around the ligand or macrocycle. Above 1 the ring opens out.

Off: hydrogen bonds, salt bridges, stacking and the rest are classified and styled separately. On: every residue inside the cutoff gets one dashed line to its closest ligand atom, with that distance. Same residues either way — only the drawing changes.

Starting the engine…

Diagram

Load a structure to begin.
Hover a residue to isolate its interactions.