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The non-heme Fe( ii ) and 2-oxoglutarate (2OG) dependent ethylene-forming enzyme (EFE) catalyzes both ethylene generation and l -Arg hydroxylation. Despite experimental and computational progress in understanding the mechanism of EFE, no EFE variant has been optimized for ethylene production while simultaneously reducing the l -Arg hydroxylation activity. In this study, we show that the two l -Arg binding conformations, associated with different reactivity preferences in EFE, lead to differences in the intrinsic electric field (IntEF) of EFE. Importantly, we suggest that applying an external electric field (ExtEF) along the Fe–O bond in the EFE·Fe( iii )·OO − ˙·2OG· l -Arg complex can switch the EFE reactivity between l -Arg hydroxylation and ethylene generation. Furthermore, we explored how applying an ExtEF alters the geometry, electronic structure of the key reaction intermediates, and the individual energy contributions of second coordination sphere (SCS) residues through combined quantum mechanics/molecular mechanics (QM/MM) calculations. Experimentally generated variant forms of EFE with alanine substituted for SCS residues responsible for stabilizing the key intermediates in the two reactions of EFE led to changes in enzyme activity, thus demonstrating the key role of these residues. Overall, the results of applying an ExtEF indicate that making the IntEF of EFE less negative and stabilizing the off-line binding of 2OG is predicted to increase ethylene generation while reducing l -Arg hydroxylation.
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This content will become publicly available on May 7, 2026
Revealing the nature of the second branch point in the catalytic mechanism of the Fe( ii )/2OG-dependent ethylene forming enzyme
The study explores the second branchpoint of the EFE catalytic mechanism, which determines the product distribution of ethylene and 3-hydroxypropionate formation using QM/MM simulations on WT and A198L variants of EFE.
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- Award ID(s):
- 2203630
- PAR ID:
- 10636250
- Editor(s):
- na
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 16
- Issue:
- 18
- ISSN:
- 2041-6520
- Page Range / eLocation ID:
- 7667 to 7684
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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