Hybrid radical-polar pathway for excision of ethylene from 2-oxoglutarate by an iron oxygenase

Rachelle A. Copeland, Shengbin Zhou, Irene Schaperdoth, Tokufu Kent C. Shoda, J. Martin Bollinger, Carsten Krebs

Research output: Contribution to journalArticlepeer-review

Abstract

Microbial ethylene-forming enzyme (EFE) converts the C3–C4 fragment of the ubiquitous primary metabolite 2-oxoglutarate (2OG) to its namesake alkene product. This reaction is very different from the simple decarboxylation of 2OG to succinate promoted by related enzymes and has inspired disparate mechanistic hypotheses. We show that EFE produces stereochemically random (equal cis and trans) 1,2-[2H2]-ethylene from (3S,4R)-[2H2]-2OG, appends an oxygen from O2 on the C1-derived (bi)carbonate, and can be diverted to w-hydroxylated monoacid products by modifications to 2OG or the enzyme. These results implicate an unusual radical-polar hybrid mechanism involving iron(II)-coordinated acylperoxycarbonate and alkylcarbonate intermediates. The mechanism explains how EFE accesses a high-energy carboxyl radical to initiate its fragmentation cascade, and it hints at capabilities of 2OG-dependent enzymes that may await discovery and exploitation.

Original languageEnglish (US)
Pages (from-to)1489-1493
Number of pages5
JournalScience
Volume373
Issue number6562
DOIs
StatePublished - Sep 24 2021

All Science Journal Classification (ASJC) codes

  • General

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