scholarly journals Rücktitelbild: Discovery of a Promiscuous Non-Heme Iron Halogenase in Ambiguine Alkaloid Biogenesis: Implication for an Evolvable Enzyme Family for Late-Stage Halogenation of Aliphatic Carbons in Small Molecules (Angew. Chem. 19/2016)

2016 ◽  
Vol 128 (19) ◽  
pp. 5968-5968
Author(s):  
Matthew L. Hillwig ◽  
Qin Zhu ◽  
Kuljira Ittiamornkul ◽  
Xinyu Liu
Keyword(s):  
Small Molecules ◽  
Late Stage ◽  
Heme Iron ◽  
Non Heme Iron ◽  
Enzyme Family

scholarly journals Nitrene Transfer Catalyzed by a Non-Heme Iron Enzyme and Enhanced by Non-Native Small-Molecule Cofactors

2019 ◽  
Author(s):  
Nathaniel Goldberg ◽  
Anders M. Knight ◽  
Ruijie Zhang ◽  
Frances H. Arnold
Keyword(s):  
Enzyme Activity ◽  
Small Molecules ◽  
Directed Evolution ◽  
Heme Iron ◽  
Transition Metal Catalysis ◽  
Chemical Bonds ◽  
Metal Catalysis ◽  
Nitrene Transfer ◽  
Non Heme Iron ◽  
Iron Center

Transition-metal catalysis is a powerful tool for the construction of chemical bonds. Here we show that a non-heme iron enzyme can catalyze olefin aziridination and nitrene C–H insertion, and that these activities can be improved by directed evolution. The non-heme iron center allows for facile modification of the primary coordination sphere by addition of metal-coordinating molecules, enabling control over enzyme activity and selectivity using small molecules.

scholarly journals Nitrene Transfer Catalyzed by a Non-Heme Iron Enzyme and Enhanced by Non-Native Small-Molecule Cofactors

2019 ◽  
Author(s):  
Nathaniel Goldberg ◽  
Anders M. Knight ◽  
Ruijie Zhang ◽  
Frances H. Arnold
Keyword(s):  
Enzyme Activity ◽  
Small Molecules ◽  
Directed Evolution ◽  
Heme Iron ◽  
Transition Metal Catalysis ◽  
Chemical Bonds ◽  
Metal Catalysis ◽  
Nitrene Transfer ◽  
Non Heme Iron ◽  
Iron Center

Transition-metal catalysis is a powerful tool for the construction of chemical bonds. Here we show that a non-heme iron enzyme can catalyze olefin aziridination and nitrene C–H insertion, and that these activities can be improved by directed evolution. The non-heme iron center allows for facile modification of the primary coordination sphere by addition of metal-coordinating molecules, enabling control over enzyme activity and selectivity using small molecules.

Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

2019 ◽  
Author(s):  
Christopher John ◽  
Greg M. Swain ◽  
Robert P. Hausinger ◽  
Denis A. Proshlyakov
Keyword(s):  
Active Site ◽  
Structural Model ◽  
Heme Iron ◽  
Chemical Transformations ◽  
Experimental Conditions ◽  
Strongly Coupled ◽  
Non Heme Iron ◽  
Reversible Redox ◽  
Wide Range ◽  
Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

Plant carotenoid cleavage oxygenases: structure–function relationships and role in development and metabolism

2019 ◽  
Vol 19 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Manoj Kumar Dhar ◽  
Sonal Mishra ◽  
Archana Bhat ◽  
Sudha Chib ◽  
Sanjana Kaul
Keyword(s):  
Higher Plants ◽  
Domain Architecture ◽  
Heme Iron ◽  
Critical Assessment ◽  
Protein Family ◽  
Regulatory Mechanisms ◽  
Non Heme Iron ◽  
Functional Aspects ◽  
Functional Understanding ◽  
Signal Production

Abstract A plant communicates within itself and with the outside world by deploying an array of agents that include several attractants by virtue of their color and smell. In this category, the contribution of ‘carotenoids and apocarotenoids’ is very significant. Apocarotenoids, the carotenoid-derived compounds, show wide representation among organisms. Their biosynthesis occurs by oxidative cleavage of carotenoids, a high-value reaction, mediated by carotenoid cleavage oxygenases or carotenoid cleavage dioxygenases (CCDs)—a family of non-heme iron enzymes. Structurally, this protein family displays wide diversity but is limited in its distribution among plants. Functionally, this protein family has been recognized to offer a role in phytohormones, volatiles and signal production. Further, their wide presence and clade-specific functional disparity demands a comprehensive account. This review focuses on the critical assessment of CCDs of higher plants, describing recent progress in their functional aspects and regulatory mechanisms, domain architecture, classification and localization. The work also highlights the relevant discussion for further exploration of this multi-prospective protein family for the betterment of its functional understanding and improvement of crops.

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