Reversible H Atom Abstraction Catalyzed by the Radical S-Adenosylmethionine Enzyme HydG

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• 作者：Benjamin R. Duffus ; Shourjo Ghose ; John W. Peters ; Joan B. Broderick
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：September 24, 2014
• 年：2014
• 卷：136
• 期：38
• 页码：13086-13089
• 全文大小：285K
• ISSN：1520-5126

文摘

The organometallic H-cluster at the active site of [FeFe]-hydrogenases is synthesized by three accessory proteins, two of which are radical S-adenosylmethionine enzymes (HydE, HydG) and one of which is a GTPase (HydF). In this work we probed the specific role of H atom abstraction in HydG-catalyzed carbon monoxide and cyanide production from tyrosine. The isotope distributions of 5鈥?deoxyadenosine and p-cresol were evaluated using deuterium-labeled tyrosine substrates in H₂O and D₂O. The observation of multiply deuterated 5鈥?deoxyadenosine and deuterated S-adenosylmethionine when the reaction is carried out in D₂O provides evidence for a 5鈥?deoxyadenosyl radical-mediated abstraction of a hydrogen atom from a solvent-exchangeable position as a reversible event.