Structural highlights
Publication Abstract from PubMedThe temperature dependence of hydride transfer from the substrate to the N5 of the FAD cofactor during the reductive half-reaction of Pleurotus eryngii aryl-alcohol oxidase (AAO) is assessed here. Kinetic isotope effects on both the pre-steady state reduction of the enzyme and its steady-state kinetics, with differently deuterated substrates, suggest an environmentally-coupled quantum-mechanical tunnelling process. Moreover, those kinetic data, along with the crystallographic structure of the enzyme in complex with a substrate analogue, indicate that AAO shows a pre-organized active site that would only require the approaching of the hydride donor and acceptor for the tunnelled transfer to take place. Modification of the enzyme's active-site architecture by replacement of Tyr92, a residue establishing hydrophobic interactions with the substrate analogue in the crystal structure, in the Y92F, Y92L and Y92W variants resulted in different temperature dependence patterns that indicated a role of this residue in modulating the transfer reaction. Protein dynamics promote hydride tunnelling in substrate oxidation by aryl-alcohol oxidase.,Carro J, Martinez-Julvez M, Medina M, Martinez AT, Ferreira P Phys Chem Chem Phys. 2017 Oct 18. doi: 10.1039/c7cp05904c. PMID:29043303[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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