Proton-Coupled Electron Transfer from Tyrosine in the Interior of a de novo Protein: Mechanisms and Primary Proton Acceptor.

ABSTRACT: Proton-coupled electron transfer (PCET) from tyrosine produces a neutral tyrosyl radical (Y^•) that is vital to many catalytic redox reactions. To better understand how the protein environment influences the PCET properties of tyrosine, we have studied the radical formation behavior of Y₃₂ in the α₃Y model protein. The previously solved α₃Y solution NMR structure shows that Y₃₂ is sequestered ∼7.7 ± 0.3 Å below the protein surface without any primary proton acceptors nearby. Here we present transient absorption kinetic data and molecular dynamics (MD) simulations to resolve the PCET mechanism associated with Y₃₂ oxidation. Y₃₂^• was generated in a bimolecular reaction with [Ru(bpy)₃]³⁺

SUBMITTER: Nilsen-Moe A 

PROVIDER: S-EPMC7315633 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature