Protein dynamics control proton transfers to the substrate on the His72Asn mutant of p-hydroxybenzolate hydroxylase

Results reveal that the reduction of His72Asn p-hydroxybenzoate hydroxylase is controlled by the protonation state of the substrate p-hydroxybenzoate, which in turn mediates flavin movement during conformational changes. Data indicate that the ionization/protonation of the substrate proceeds via hydronium or hydroxide reacting with the enzyme-ligand complex.