Protein sites, features and motifs Protein binding sites 1.8 Enzyme active site Protein-nucleic acid binding sites Protein functional sites Binding sites in proteins, including cleavage sites (for a proteolytic enzyme or agent), key residues involved in protein folding, catalytic residues (active site) of an enzyme, ligand-binding (non-catalytic) residues of a protein, such as sites that bind metal, prosthetic groups or lipids, RNA and DNA-binding proteins and binding sites etc. Protein cleavage sites Protein key folding sites Protein_binding_sites