NMR studies of the active site of isopenicillin N synthase, a non-heme iron(II) enzyme

Biochemistry ◽  
1991 ◽  
Vol 30 (50) ◽  
pp. 11653-11659 ◽  
Author(s):  
Li June Ming ◽  
Lawrence Que ◽  
Aidas Kriauciunas ◽  
Charles A. Frolik ◽  
Victor J. Chen
Keyword(s):  
Active Site ◽  
Heme Iron ◽  
Nmr Studies ◽  
Non Heme Iron ◽  
Isopenicillin N

Structure–function studies of the non-heme iron active site of isopenicillin N synthase: some implications for catalysis

2000 ◽  
Vol 86 (2-3) ◽  
pp. 109-118 ◽  
Author(s):  
Rachel Kreisberg-Zakarin ◽  
Ilya Borovok ◽  
Michaela Yanko ◽  
Felix Frolow ◽  
Yair Aharonowitz ◽  
...  
Keyword(s):  
Structure Function ◽  
Active Site ◽  
Heme Iron ◽  
Non Heme Iron ◽  
Isopenicillin N

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.

scholarly journals Activation modes in biocatalytic radical cyclization reactions

2021 ◽  
Author(s):  
Yuxuan Ye ◽  
Haigen Fu ◽  
Todd K Hyster
Keyword(s):  
Heme Iron ◽  
Radical Cyclization ◽  
Cytochrome P450 Monooxygenases ◽  
Radical Cyclizations ◽  
Cyclization Reactions ◽  
Complex Molecules ◽  
P450 Monooxygenases ◽  
Non Heme Iron ◽  
Essential Reactions ◽  
Isopenicillin N

Abstract Radical cyclizations are essential reactions in the biosynthesis of secondary metabolites and the chemical synthesis of societally valuable molecules. In this review, we highlight the general mechanisms utilized in biocatalytic radical cyclizations. We specifically highlight cytochrome P450 monooxygenases (P450s) involved in the biosynthesis of mycocyclosin and vancomycin, non-heme iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGDs) used in the biosynthesis of kainic acid, scopolamine, and isopenicillin N, and radical S-adenosylmethionine (SAM) enzymes that facilitate the biosynthesis of oxetanocin A, menaquinone, and F420. Beyond natural mechanisms, we also examine repurposed flavin-dependent ‘ene’-reductases (ERED) for non-natural radical cyclization. Overall, these general mechanisms underscore the opportunity for enzymes to augment and enhance the synthesis of complex molecules using radical mechanisms.

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

2019 ◽  
Vol 123 (37) ◽  
pp. 7785-7793 ◽  
Author(s):  
Christopher W. John ◽  
Greg M. Swain ◽  
Robert P. Hausinger ◽  
Denis A. Proshlyakov
Keyword(s):  
Active Site ◽  
Heme Iron ◽  
Conformational Switching ◽  
Strongly Coupled ◽  
Non Heme Iron

Evidence for the involvement of non-heme iron in the active site of hydrogenase from Desulfovibrio vulgaris

1971 ◽  
Vol 234 (3) ◽  
pp. 525-530 ◽  
Author(s):  
J. Legall ◽  
D.V. Dervartanian ◽  
E. Spilker ◽  
Jin-Po Lee ◽  
H.D. Peck
Keyword(s):  
Active Site ◽  
Heme Iron ◽  
Desulfovibrio Vulgaris ◽  
Non Heme Iron

scholarly journals Structural characterization of a non-heme iron active site in zeolites that hydroxylates methane

2018 ◽  
Vol 115 (18) ◽  
pp. 4565-4570 ◽  
Author(s):  
Benjamin E. R. Snyder ◽  
Lars H. Böttger ◽  
Max L. Bols ◽  
James J. Yan ◽  
Hannah M. Rhoda ◽  
...  
Keyword(s):  
Active Site ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Heme Iron ◽  
Zeolite Lattice ◽  
Non Heme Iron ◽  
Bonding Interaction ◽  
Lattice Density ◽  
X Ray Absorption

Iron-containing zeolites exhibit unprecedented reactivity in the low-temperature hydroxylation of methane to form methanol. Reactivity occurs at a mononuclear ferrous active site, α-Fe(II), that is activated by N2O to form the reactive intermediate α-O. This has been defined as an Fe(IV)=O species. Using nuclear resonance vibrational spectroscopy coupled to X-ray absorption spectroscopy, we probe the bonding interaction between the iron center, its zeolite lattice-derived ligands, and the reactive oxygen. α-O is found to contain an unusually strong Fe(IV)=O bond resulting from a constrained coordination geometry enforced by the zeolite lattice. Density functional theory calculations clarify how the experimentally determined geometric structure of the active site leads to an electronic structure that is highly activated to perform H-atom abstraction.

scholarly journals Active-site-mediated elimination of hydrogen fluoride from a fluorinated substrate analogue by isopenicillin N synthase

2004 ◽  
Vol 382 (2) ◽  
pp. 659-666 ◽  
Author(s):  
Annaleise R. GRUMMITT ◽  
Peter J. RUTLEDGE ◽  
Ian J. CLIFTON ◽  
Jack E. BALDWIN
Keyword(s):  
Lewis Acid ◽  
Hydrogen Fluoride ◽  
Mechanism Of Action ◽  
Active Site ◽  
Nmr Studies ◽  
X Ray ◽  
Substrate Analogue ◽  
Haem Iron ◽  
Active Site Region ◽  
Isopenicillin N

Isopenicillin N synthase (IPNS) is a non-haem iron oxidase that catalyses the formation of bicyclic isopenicillin N from δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine (ACV). In this study we report a novel activity for the iron of the IPNS active site, which behaves as a Lewis acid to catalyse the elimination of HF from the fluorinated substrate analogue, δ-(L-α-aminoadipoyl)-L-cysteinyl-D-β-fluorovaline (ACβFV). X-Ray crystallographic studies of IPNS crystals grown anaerobically with ACβFV reveal that the valinyl β-fluorine is missing from the active site region, and suggest the presence of the unsaturated tripeptide δ-(L-α-aminoadipoyl)-L-cysteinyl-D-isodehydrovaline in place of substrate ACβFV. 19F NMR studies confirm the release of fluoride from ACβFV in the presence of the active IPNS enzyme. These results suggest a new mode of reactivity for the IPNS iron centre, a mechanism of action that has not previously been reported for any of the iron oxidase enzymes.

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