Download MendeleyProtein dynamics promote hydride tunnelling in substrate oxidation by aryl-alcohol oxidase.
Carro, J., Martinez-Julvez, M., Medina, M., Martinez, A.T., Ferreira, P.(2017) Phys Chem Chem Phys 19: 28666-28675
- PubMed: 29043303
- DOI: https://doi.org/10.1039/c7cp05904c
- Primary Citation of Related Structures:
5OC1 - PubMed Abstract:
The 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.
Organizational Affiliation:
Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain. atmartinez@cib.csic.es.
