Identification of the High Affinity Mn2+Binding Site of Bacteriophage λ Phosphoprotein Phosphatase:  Effects of Metal Ligand Mutations on Electron Paramagnetic Resonance Spectra and Phosphatase Activities†

Biochemistry ◽  
2001 ◽  
Vol 40 (30) ◽  
pp. 8918-8929 ◽  
Author(s):  
Daniel J. White ◽  
Nicholas J. Reiter ◽  
Robert A. Sikkink ◽  
Lian Yu ◽  
Frank Rusnak
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Binding Site ◽  
Bacteriophage Λ ◽  
Paramagnetic Resonance ◽  
Phosphatase Activities ◽  
Phosphoprotein Phosphatase ◽  
High Affinity ◽  
Electron Paramagnetic ◽  
Metal Ligand

scholarly journals Electron-paramagnetic-resonance studies on nitrogenase of Klebsiella pneumoniae. Evidence for acetylene- and ethylene-nitrogenase transient complexes

1978 ◽  
Vol 173 (1) ◽  
pp. 277-290 ◽  
Author(s):  
D J Lowe ◽  
R R Eady ◽  
R N F Thorneley
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Klebsiella Pneumoniae ◽  
Binding Site ◽  
Dissociation Constants ◽  
Paramagnetic Resonance ◽  
Fe Protein ◽  
Low Concentrations ◽  
Direct Binding ◽  
Electron Paramagnetic ◽  
Single Binding Site

Klebsiella pneumoniae nitrogenase exhibited four new electron-paramagnetic-resonance signals during turnover at 10 degrees C, pH7.4, which were assigned to intermediates present in low concentrations in the steady state. 57Fe-substituted Mo–Fe protein showed that they arose from Fe–S clusters in the Mo–Fe protein of nitrogenase. The new signals are designated: Ic, g values at 4.67, 3.37 and approx. 2.0; VI, g values at 2.125, 2.000 and 2.000; VII, g values at 5.7 and 5.4; VIII, g values at 2.092, 1.974 and 1.933. The sharp axial signal VI arises from a Fe4S4 cluster at the −1 oxidation level. This signal was only detected in the presence of ethylene and provides the first evidence of an enzyme–product complex for nitrogenase. [13C]Acetylene and [13C]ethylene provided no evidence for direct binding of this substrate and product to the Fe–S clusters giving rise to these signals. The dependence of signal intensities on acetylene concentration indicated two types of binding site, with apparent dissociation constants K less than 16 micron and K approximately 13mM. A single binding site for ethylene (K=1.5mM) was detected. A scheme is proposed for the mechanism of reduction of acetylene to ethylene and inhibition of this reaction by CO.

scholarly journals Exploring template-bound dinuclear copper porphyrin nanorings by EPR spectroscopy

2016 ◽  
Vol 7 (12) ◽  
pp. 6952-6960 ◽  
Author(s):  
Sabine Richert ◽  
Jonathan Cremers ◽  
Harry L. Anderson ◽  
Christiane R. Timmel
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Molecular Geometry ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Copper Porphyrin ◽  
Ligand Interactions ◽  
Electron Paramagnetic ◽  
Metal Ligand

Electron paramagnetic resonance spectroscopy reveals the molecular geometry and metal–ligand interactions in template-bound ten-membered bis-copper porphyrin nanorings.

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