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Non‐Coordinative Binding of O 2 at the Active Center of a Copper‐Dependent Enzyme
Author(s) -
Leisinger Florian,
Miarzlou Dzmitry A.,
Seebeck Florian P.
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202014981
Subject(s) - chemistry , active site , diradical , redox , active center , enzyme , stereochemistry , metal , reactivity (psychology) , photochemistry , electron transfer , singlet state , inorganic chemistry , organic chemistry , medicine , physics , alternative medicine , pathology , nuclear physics , excited state
Molecular oxygen (O 2 ) is a sustainable oxidation reagent. O 2 is strongly oxidizing but kinetically stable and its final reaction product is water. For these reasons learning how to activate O 2 and how to steer its reactivity along desired reaction pathways is a longstanding challenge in chemical research. [1] Activation of ground‐state diradical O 2 can occur either via conversion to singlet oxygen or by one‐electron reduction to superoxide. Many enzymes facilitate activation of O 2 by direct fomation of a metal‐oxygen coordination complex concomitant with inner sphere electron transfer. The formylglycine generating enzyme (FGE) is an unusual mononuclear copper enzyme that appears to follow a different strategy. Atomic‐resolution crystal structures of the precatalytic complex of FGE demonstrate that this enzyme binds O 2 juxtaposed, but not coordinated to the catalytic Cu I . Isostructural complexes that contain Ag I instead of Cu I or nitric oxide instead of O 2 confirm that formation of the initial oxygenated complex of FGE does not depend on redox activity. A stepwise mechanism that decouples binding and activation of O 2 is unprecedented for metal‐dependent oxidases, but is reminiscent of flavin‐dependent enzymes.