Analyze protein-ligand interactions in PDB structures using PLIP (Protein-Ligand Interaction Profiler). Use this skill when: (1) Analyzing binding interactions from a PDB structure file, (2) Identifying hydrogen bonds, hydrophobic contacts, π-stacking, salt bridges, and water bridges, (3) Generating 3D visualizations of protein-ligand complexes, (4) Creating interaction summary reports for drug discovery.