Proximal- and distal-type αKG binding to the Fe( ii ) centre might play a crucial role in fine-tuning the catalysis of αKG-dependent non-haem iron enzymes.

The cyst(e)ine/glutathione (GSH)/glutathione peroxidase 4 (GPX4) axis is the most frequently targeted pathway to trigger the ferroptosis cascade and suppress tumor growth. Two recent studies present additional mechanisms underlying cystine starvation-induced ferroptosis apart from impaired GSH synthesis.

Significance: Ferroptosis is featured by the accumulation of polyunsaturated-lipid peroxidation on cellular membranes in an iron-dependent manner. Ferroptosis has been implicated in various pathophysiological processes, including cancer, neurodegeneration, and ischemia-reperfusion tissue injury. However, our understanding about the dynamic and context-specific regulation of ferroptosis remains incomplete. Recent Advances: As the major substrate for peroxidation, the cellular lipidome regulates ferroptosis sensitivity and execution by controlling the abundance and availability of polyunsaturated-lipids for peroxidative modifications. In turn, the cellular lipidome is regulated by a complex network of enzymes and transporters, as well as upstream layers of receptors, kinases, and transcription factors. A number of research has shed light on the link between lipid metabolism and ferroptosis. Here, we summarize our current knowledge on the role of the lipidome and associated protein regulators in various stages of ferroptosis, ranging from initiation, execution to cell death evasion by cells experiencing ferroptotic stress. Critical Issues: This review provides an overview of the mechanisms underlying lipid peroxidation and ferroptosis by discussing the lipid species that directly contribute to lipid peroxidation and ferroptosis, how cells regulate the abundances of these pro-ferroptosis lipids, how lipid peroxidation causes cell death, and how cells prevent and repair membrane lipid damage under ferroptotic conditions. Future Directions: Cell fate regulation in vivo could be different from in vitro culture settings. We envision that a comprehensive and detailed understanding about these important questions in the dynamic regulation of ferroptosis in vivo will accelerate our development of ferroptosis-targeted therapies to improve human health.

Protein chemical modifications are important tools for elucidating chemical and biological functions of proteins. Several strategies have been developed to implement these modifications, including enzymatic tailoring reactions, unnatural amino acid incorporation using the expanded genetic codes, and recognition-driven transformations. These technologies have been applied in metalloenzyme studies, specifically in dissecting their mechanisms, improving their enzymatic activities, and creating artificial enzymes with non-natural activities. Herein, we summarize some of the recent efforts in these areas with an emphasis on a few metalloenzyme case studies.

Modulation of OvoA _Mtht 's dual activities: sulfoxide synthase and thiol oxygenase.

α-Ketoglutarate-dependent non-haem iron (αKG-NHFe) enzymes play a crucial role in natural product biosynthesis, and in some cases exhibiting multifunctional catalysis capability. This study focuses on αKG-NHFe enzyme FtmOx1, which catalyzes endoperoxidation, dealkylation, and alcohol oxidation reactions in verruculogen biosynthesis. We explore the hypothesis that the conformational dynamics of the active site Y224 confer the multifunctional activities of FtmOx1-catalysis. Utilizing Y224-to-3,5-difluorotyrosine-substituted FtmOx1, produced via the amber codon suppression method, we conducted ¹⁹F NMR characterization to investigate FtmOx1's structural flexibility. Subsequent biochemical and X-ray crystallographic analyses provided insights into how specific conformations of FtmOx1–substrate complexes influence their catalytic activities. These findings underscore the utility of ¹⁹F NMR as a powerful tool for elucidating the complex mechanisms of multifunctional enzymes, offering potential avenues for developing biocatalytic processes to produce novel therapeutic agents harnessing their unique catalytic properties.