Ultrafast Dynamics and Catalytic Mechanism of Fatty Acid Photodecarboxylase. (10th November 2022)

• Record Type: Journal Article
• Authors: Wu, Ruiqi; Li, Xiankun; Wang, Lijuan; Zhong, Dongping
• Is Part Of: Angewandte Chemie. Volume 134:Number 50(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-10
• Subjects: Catalytic Photocycle -- Electron Transfer -- Flavin Photoenzymes -- Hydrocarbon Formation -- Photodecarboxylation; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202209180
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Fatty acid photodecarboxylase is a newly discovered flavin photoenzyme that converts a carboxylic acid into a hydrocarbon and a carbon dioxide molecule through decarboxylation. The enzymatic reactions are poorly understood. In this study, we carefully characterized its dynamic evolution with femtosecond spectroscopy. We observed initial electron transfer from the substrate to the flavin cofactor in 347 ps with a stretched dynamic behavior and subsequently captured the critical carbonyloxy radical. The dominant process following this step was decarboxylation in 5.8 ns to form an alkyl radical and a carbon dioxide molecule. We further identified the absorption bands of two carbonyloxy and alkyl radical intermediates. The overall enzymatic quantum efficiency determined by our obtained timescales is 0.81, consistent with the steady‐state value. The results are essential to the elucidation of the enzyme mechanism and catalytic photocycle, providing a molecular basis for potential design of flavin‐based artificial photoenzymes. Abstract : Fatty acid photodecarboxylase converts a carboxylic acid into a hydrocarbon and a carbon dioxide molecule through decarboxylation. Two critical carbonyloxy and alkyl radical intermediates in the catalytic reactions were captured by deep UV detection, and their dynamics were determined with actual reaction timescales, revealing the molecular mechanism of the enzymatic reaction and mapping out the catalytic photocycle of this efficient photoenzyme.