Identification of Amino Acid Residues Responsible for C-H Activation in Type-III Copper Enzymes by Generating Tyrosinase Activity in a Catechol Oxidase.

ABSTRACT: Tyrosinases (TYRs) catalyze the hydroxylation of phenols and the oxidation of the resulting o-diphenols to o-quinones, while catechol oxidases (COs) exhibit only the latter activity. Aurone synthase (AUS) is not able to react with classical tyrosinase substrates, such as tyramine and l-tyrosine, while it can hydroxylate its natural substrate isoliquiritigenin. The structural difference of TYRs, COs, and AUS at the heart of their divergent catalytic activities is still a puzzle. Therefore, a library of 39 mutants of AUS from Coreopsis grandiflora (CgAUS) was generated and the activity studies showed that the reactivity of the three conserved histidines (HisA₂ , HisB₁ , and HisB₂ ) is tuned by their adjacent residues (HisB₁ +1, HisB₂ +1,

SUBMITTER: Kampatsikas I 

PROVIDER: S-EPMC7693034 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature