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.

scholarly journals Structural studies on the reaction of isopenicillin N synthase with the substrate analogue delta-(l-alpha-aminoadipoyl)-l-cysteinyl-d-alpha-aminobutyrate

2003 ◽  
Vol 372 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Alexandra J. LONG ◽  
Ian J. CLIFTON ◽  
Peter L. ROACH ◽  
Jack E. BALDWIN ◽  
Christopher J. SCHOFIELD ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Active Site ◽  
Structural Studies ◽  
Product Selectivity ◽  
Substrate Analogue ◽  
Modelling Studies ◽  
Key Residues ◽  
Haem Iron ◽  
Shed Light ◽  
Isopenicillin N

Isopenicillin N synthase (IPNS) is a non-haem iron(II) oxidase which catalyses the biosynthesis of isopenicillin N from the tripeptide δ-(l-α-aminoadipoyl)-l-cysteinyl-d-valine (ACV). Herein we report crystallographic studies to investigate the reaction of IPNS with the truncated substrate analogue δ-(l-α-aminoadipoyl)-l-cysteinyl-d-α-aminobutyrate (ACAb). It has been reported previously that this analogue gives rise to three β-lactam products when incubated with IPNS: two methyl penams and a cepham. Crystal structures of the IPNS–Fe(II)–ACAb and IPNS–Fe(II)–ACAb–NO complexes have now been solved and are reported herein. These structures and modelling studies based on them shed light on the diminished product selectivity shown by IPNS in its reaction with ACAb and further rationalize the presence of certain key residues at the IPNS active site.

First example of a stable 1,1-bidentate Lewis acid based on boron and zirconium: synthesis, reactivity, X-ray analysis and NMR studies

1994 ◽  
pp. 127 ◽  
Author(s):  
Ewa Skrzypczak-Jankun ◽  
Bruce V. Cheesman ◽  
Bin Zheng ◽  
Richard M. Lemert ◽  
Siddharta Asthana ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Nmr Studies ◽  
X Ray

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

The structure of chitinases and prospects for structure-based drug design

1995 ◽  
Vol 73 (S1) ◽  
pp. 1142-1146 ◽  
Author(s):  
Jon D. Robertus ◽  
P. John Hart ◽  
Arthur F. Monzingo ◽  
Edward Marcotte ◽  
Thomas Hollis
Keyword(s):  
Drug Design ◽  
Small Molecules ◽  
Mechanism Of Action ◽  
Active Site ◽  
Antifungal Agents ◽  
Structure Based Drug Design ◽  
X Ray ◽  
Class Ii Chitinase ◽  
Transition State Geometry ◽  
Chitinase Inhibitors

Many fungi, including pathogenic strains, require proper chitin metabolism to assure normal cell wall replication. Chitinase hydrolyzes chitin; inhibition of endogenous chitinases or application of extracellular chitinases can disrupt fungal division. It is possible that chitinase inhibitors could be used as antifungal agents. We have solved the X-ray structure of a class II chitinase from barley and proposed a mechanism of action. The enzyme has a structural core similar to lysozyme and probably acts in a similar catalytic manner. The enzyme structure can, in principle, be used to identify small molecules that will bind avidly to the active site and act as inhibitors. Those inhibitors that embody transition state geometry are likely to be particularly effective. Key words: chitinase, mechanism of action, drug design.

X-ray absorption studies of the ferrous active site of isopenicillin N synthase and related model complexes

Biochemistry ◽  
1993 ◽  
Vol 32 (26) ◽  
pp. 6664-6673 ◽  
Author(s):  
Clayton R. Randall ◽  
Yan Zang ◽  
Anne E. True ◽  
Lawrence Que ◽  
John M. Charnock ◽  
...  
Keyword(s):  
Active Site ◽  
Model Complexes ◽  
X Ray ◽  
Related Model ◽  
Absorption Studies ◽  
X Ray Absorption ◽  
Isopenicillin N

X-ray absorption spectroscopic studies of the high-spin iron(II) active site of isopenicillin N synthase: evidence for iron-sulfur interaction in the enzyme-substrate complex

Biochemistry ◽  
1992 ◽  
Vol 31 (19) ◽  
pp. 4596-4601 ◽  
Author(s):  
Robert A. Scott ◽  
Shengke Wang ◽  
Marly K. Eidsness ◽  
Aidas Kriauciunas ◽  
Charles A. Frolik ◽  
...  
Keyword(s):  
High Spin ◽  
Active Site ◽  
Spectroscopic Studies ◽  
X Ray ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Iron Sulfur ◽  
X Ray Absorption ◽  
Isopenicillin N ◽  
High Spin Iron

scholarly journals Structure of theArabidopsis thalianaTOP2 oligopeptidase

2014 ◽  
Vol 70 (5) ◽  
pp. 555-559 ◽  
Author(s):  
Ruiying Wang ◽  
Krithika Rajagopalan ◽  
Kianoush Sadre-Bazzaz ◽  
Magali Moreau ◽  
Daniel F. Klessig ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Innate Immunity ◽  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Active Site ◽  
Conclusive Evidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thimet Oligopeptidase ◽  
Active Site Region

Thimet oligopeptidase (TOP) is a zinc-dependent metallopeptidase. Recent studies suggest thatArabidopsis thalianaTOP1 and TOP2 are targets for salicylic acid (SA) binding and participate in SA-mediated plant innate immunity. The crystal structure ofA. thalianaTOP2 has been determined at 3.0 Å resolution. Comparisons to the structure of human TOP revealed good overall structural conservation, especially in the active-site region, despite their weak sequence conservation. The protein sample was incubated with the photo-activated SA analog 4-azido-SA and exposed to UV irradiation before crystallization. However, there was no conclusive evidence for the binding of SA based on the X-ray diffraction data. Further studies are needed to elucidate the molecular mechanism of how SA regulates the activity ofA. thalianaTOP1 and TOP2.

New Copper Compounds with Antiplatelet Aggregation Activity

2019 ◽  
Vol 15 (8) ◽  
pp. 850-862
Author(s):  
Mirthala Flores-García ◽  
Juan Manuel Fernández-G. ◽  
Cristina Busqueta-Griera ◽  
Elizabeth Gómez ◽  
Simón Hernández-Ortega ◽  
...  
Keyword(s):  
Schiff Base ◽  
Solid State ◽  
Thrombotic Event ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Antiplatelet Aggregation ◽  
Aggregation Activity ◽  
L1 And L2

Background: Ischemic heart disease, cerebrovascular accident, and venous thromboembolism have the presence of a thrombotic event in common and represent the most common causes of death within the population. Objective: Since Schiff base copper(II) complexes are able to interact with polyphosphates (PolyP), a procoagulant and potentially prothrombotic platelet agent, we investigated the antiplatelet aggregating properties of two novel tridentate Schiff base ligands and their corresponding copper( II) complexes. Methods: The Schiff base ligands (L1) and (L2), as well as their corresponding copper(II) complexes (C1) and (C2), were synthesized and characterized by chemical analysis, X-ray diffraction, mass spectrometry, and UV-Visible, IR and far IR spectroscopy. In addition, EPR studies were carried out for (C1) and (C2), while (L1) and (L2) were further analyzed by 1H and 13C NMR. Tests for antiplatelet aggregation activities of all of the four compounds were conducted. Results: X-ray diffraction studies show that (L1) and (L2) exist in the enol-imine tautomeric form with a strong intramolecular hydrogen bond. NMR studies show that both ligands are found as enol-imine tautomers in CDCl3 solution. In the solid state, the geometry around the copper(II) ion in both (C1) and (C2) is square planar. EPR spectra suggest that the geometry of the complexes is similar to that observed in the solid state by X-ray crystallography. Compound (C2) exhibited the strongest antiplatelet aggregation activity. Conclusion: Schiff base copper(II) complexes, which are attracting increasing interest, could represent a new approach to treat thrombosis by blocking the activity of PolyP with a potential anticoagulant activity and, most importantly, demonstrating no adverse bleeding events.

Sign in / Sign up

Export Citation Format

Share Document