Enzymatic control of dioxygen binding and functionalization of the flavin cofactor

TitleEnzymatic control of dioxygen binding and functionalization of the flavin cofactor
Publication TypeJournal Article
Year of Publication2018
AuthorsSaleem-Batcha R., Stull F., Sanders J.N, Moore BS, Palfey B.A, Houk K.N, Teufel R.
JournalProceedings of the National Academy of Sciences of the United States of America
Date Published2018/05
Type of ArticleArticle
ISBN Number0027-8424
Accession NumberWOS:000431639100051
Keywordsactive-site; Bioengineering; dependent monooxygenases; EncM; FAD; flavin-N5-oxide; flavoenzymes; molecular-oxygen; monooxygenase; pathways; reaction-mechanism; reactivity; Science & Technology - Other Topics; solvent; urate oxidase

The reactions of enzymes and cofactors with gaseous molecules such as dioxygen (O-2) are challenging to study and remain among the most contentious subjects in biochemistry. To date, it is largely enigmatic how enzymes control and fine-tune their reactions with O-2, as exemplified by the ubiquitous flavin-dependent enzymes that commonly facilitate redox chemistry such as the oxygenation of organic substrates. Here we employ O-2-pressurized X-ray crystallography and quantum mechanical calculations to reveal how the precise positioning of O-2 within a flavoenzyme's active site enables the regio-specific formation of a covalent flavin-oxygen adduct and oxygenating species (i.e., the flavin-N5-oxide) by mimicking a critical transition state. This study unambiguously demonstrates how enzymes may control the O-2 functionalization of an organic cofactor as prerequisite for oxidative catalysis. Our work thus illustrates how O-2 reactivity can be harnessed in an enzymatic environment and provides crucial knowledge for future rational design of O-2-reactive enzymes.

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