Ultrafast photooxidation of semireduced flavin in fatty acid photodecarboxylase.

ABSTRACT: The initial photoproduct of the natural photoenzyme fatty acid photodecarboxylase involves the flavin anion radical flavin adenine dinucleotide (FAD^•-). Using spectrally resolved ultrafast transient absorption spectroscopy, we demonstrate that FAD^•- photoexcitation in the absence of substrate leads to the formation of the oxidized flavin FAD_ox (the resting state in the catalytic cycle) within 100 femtoseconds. While this feature is similar to that occurring in flavoprotein oxidases, the ensuing photocycle is more complex. Upon excitation at the lowest-energy transition, the ejected electron is initially captured as a hydrated electron (_e^-_H) before transferring to a secondary acceptor in 2.5 picoseconds and returning to the f

SUBMITTER: Vos MH 

PROVIDER: S-EPMC12448124 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature