Thermodynamics of Iron(II) and Substrate Binding to the Ethylene-Forming Enzyme

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The ethylene-forming enzyme (EFE) catalyzes the oxidative decarboxylation of 2OG to succinate and CO2 to generate a highly reactive iron species that hydroxylates a specific alkane C–H bond, in this case targeting l-arginine (Arg) for hydroxylation. However, the prominently observed reactivity of EFE is the transformation of 2OG into ethylene and three molecules of CO2. Crystallographic and biochemical studies have led to several proposed mechanisms for this two-fold reactivity, but the detailed reaction steps are still obscure. In this work the thermodynamics associated with iron(II), 2OG, and Arg binding to EFE are studied using calorimetry (isothermal titration calorimetry and differential scanning calorimetry) to gain insight into how these binding equilibria organize the active site of EFE, which may have an impact on the O2 activation pathways observed in this system. Find out more research by the Emerson Group.

Li M, Martinez S, Hausinger RP, Emerson JP. Biochemistry. 2018 Oct 2;57(39):5696. (DOI: 10.1021/acs.biochem.8b00730)


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