From Synthetic to Biological Fe4S4 Complexes: Redox Properties Correlated to Function of Radical S-Adenosyl-L-methionine Enzymes

0535389 - ÚFCH JH 2021 RIV DE eng J - Journal Article
Bím, Daniel - Alonso-Gil, Santiago - Srnec, Martin
From Synthetic to Biological Fe4S4 Complexes: Redox Properties Correlated to Function of Radical S-Adenosyl-L-methionine Enzymes.
ChemPlusChem. Roč. 85, č. 11 (2020), s. 2534-2541. ISSN 2192-6506. E-ISSN 2192-6506
R&D Projects: GA ČR(CZ) GA18-13093S
Institutional support: RVO:61388955
Keywords : S Adenosylmethionine * 5-Thyminyl-5,6-Dihydrothymine * Spore Photoproduct Lyase
OECD category: Physical chemistry
Impact factor: 2.863, year: 2020
Method of publishing: Limited access

Employing the computational protocol for calculation of reduction potentials of the Fe4S4- containing species validated using a representative series of well-defined synthetic complexes, we focused on redox properties of two prototypical radical SAM enzymes to reveal how they transform SAM into the reactive 5’-deoxyadenosyl radical, and how they tune this radical for its proper
biological function. We found the reduction potential of SAM is indeed elevated by 0.3-0.4 V upon coordination to Fe4S4, which was previously speculated in the literature. This makes a generation of 5’-deoxyadenosyl radical from SAM less endergonic (by ~7-9 kcal mol-1
) and hence more feasible in both enzymes as compared to the identical process in water. Next, our calculations indicate that the
enzyme-bound 5’-deoxyadenosyl radical has a significantly lower reduction potential than in referential aqueous solution, which may help the enzymes to suppress potential side redox reactions and simultaneously elevate its proton-philic character, which may, in turn, be competent for the radical hydrogen-atom abstraction ability.
Permanent Link: http://hdl.handle.net/11104/0313429