Evidence for flavin movement in the function of p-hydroxybenzoate hydroxylase from studies of the mutant Arg220Lys

Mutations at position 220 change the stability of the conformational states of the flavin of p-hydroxybenzoate hydroxylase and thus lead to changes in enzyme catalysis. The R220K enzyme stabilizes the conformation with flavin 'out' more than the wild type (WT) enzyme does, which lowers the R220K enzyme's catalytic efficiency. Catalytic mechanisms of the mutant R220K enzyme and the WT enzymes differ, as with partial hydroxylation of pOHB by R220K.