scholarly journals Redox Properties of Wild-Type, Cys69Ala, and Cys69Ser Azotobacter Vinelandii Flavodoxin II as Measured by Cyclic Voltammetry and EPR Spectroscopy

1996 ◽  
Vol 235 (1-2) ◽  
pp. 167-172 ◽  
Author(s):  
Elles Steensma ◽  
Hendrik A. Heering ◽  
Wilfred R. Hagen ◽  
Carlo P. M. Mierlo
Keyword(s):  
Cyclic Voltammetry ◽  
Epr Spectroscopy ◽  
Azotobacter Vinelandii ◽  
Redox Properties ◽  
Wild Type

scholarly journals Redox properties and EPR spectroscopy of the P clusters of Azotobacter vinelandii MoFe protein

1993 ◽  
Vol 212 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Antonio J. PIERIK ◽  
Hans WASSINK ◽  
Huub HAAKER ◽  
Wilfred R. HAGEN
Keyword(s):  
Epr Spectroscopy ◽  
Azotobacter Vinelandii ◽  
Redox Properties ◽  
Mofe Protein

Untersuchungen an biochemisch wirksamen Ligandensystemen, V

1972 ◽  
Vol 27 (10) ◽  
pp. 1131-1136 ◽  
Author(s):  
P. Barz ◽  
H. P. Fritz
Keyword(s):  
Cyclic Voltammetry ◽  
Radical Cation ◽  
Epr Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Metal Cations ◽  
Redox Properties ◽  
Neutral Molecule ◽  
Ligand Field ◽  
Ligand Field Spectra

1,2-Dimethylhydrazine co-ordinates to numerous metal cations. The structures of the complexes of Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg and Pt are discussed and the complexing abilities of the 1,2-dimethylhydrazine molecule are determined on the basis of the ligand field spectra of the nickel and the chromium derivative.The results of polarography, cyclic voltammetry and photoelectron spectroscopy yield evidence on the redox properties of the neutral molecule. By means of EPR spectroscopy the nature of the radical products obtained by irradiation of 1,2-dimethylhydrazine, especially of the radical cation, is determined.

Integrity and redox properties of homogeneous and heterogeneous DNA films on gold surface probed by cyclic voltammetry

2002 ◽  
Vol 413 (1-2) ◽  
pp. 218-223 ◽  
Author(s):  
Hellas C.M Yau ◽  
Hing Leung Chan ◽  
Sen-fang Sui ◽  
Mengsu Yang
Keyword(s):  
Cyclic Voltammetry ◽  
Gold Surface ◽  
Redox Properties ◽  
Dna Films

Application of a Novel Modified Electrode Based on NaY-Encapsulated Co(PAN) Complex

2008 ◽  
Vol 587-588 ◽  
pp. 109-113
Author(s):  
C. Teixeira ◽  
P. Parpot ◽  
Isabel Neves ◽  
António Maurício C. Fonseca
Keyword(s):  
Cyclic Voltammetry ◽  
Chemical Analysis ◽  
Aqueous Medium ◽  
Surface Analysis ◽  
Modified Electrode ◽  
Modified Electrodes ◽  
Redox Properties ◽  
New Method ◽  
Y Zeolite

CoPAN complex has been entrapped in the supercages of Y zeolite and the redox properties of this zeolite-encapsulated complex were investigated by cyclic voltammetry with a new method for the preparation of carbon toray-zeolite-modified electrode. Formation of the CoPAN complex was ascertained by surface analysis (SEM, XRD), chemical analysis (CA), spectroscopy methods (FTIR and UV/vis) and cyclic voltammetry in aqueous medium with zeolite-modified electrodes. The cyclic voltammetry studies obtained with a zeolite-modified electrode shows evidence for electroactivity restricted to boundary associated CoPAN complex.

Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

2013 ◽  
Vol 68 (5-6) ◽  
pp. 458-466 ◽  
Author(s):  
Iris Klawitter ◽  
Steffen Meyer ◽  
Serhiy Demeshko ◽  
Franc Meyer
Keyword(s):  
Cyclic Voltammetry ◽  
Redox Properties ◽  
Spin States ◽  
Imidazolium Salts ◽  
Tetradentate Ligands ◽  
Square Planar ◽  
Hybrid Ligands

Two methylene-bridged bis(imidazolium) salts [H4L1](PF6)2 and [H4L2](PF6)2 with appended amide groups have been synthesized which, after deprotonation, may serve as potentially tetradentate ligands providing two bis(imidazole-2-ylidene) and two amide donors. Using [H4L1](PF6)2, a square-planar nickel(II) complex [NiL1] and a six-coordinate bis(ligand) iron(II) complex [Fe(HL1)2] have been isolated and structurally characterized. Their low-spin states have been confirmed spectroscopically, and their redox properties have been studied by cyclic voltammetry. Oxidations are metal-centered to give NiIII and FeIII species, respectively

Redox Properties of Iron Complexes with Pentadentate Bispidine Ligands

2014 ◽  
Vol 67 (3) ◽  
pp. 398 ◽  
Author(s):  
Peter Comba ◽  
Hubert Wadepohl ◽  
Arkadius Waleska
Keyword(s):  
Aqueous Solution ◽  
Cyclic Voltammetry ◽  
Coordination Chemistry ◽  
Aqueous Solutions ◽  
Iron Complexes ◽  
Redox Properties

The solution coordination chemistry of iron complexes with the pentadentate bispidine ligands L1, L2, and L3 (dimethyl 9-oxo-2,4-di(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarboxylate derivatives) was examined. While in acetonitrile, (L1,2)FeII/III species have a preference for Cl– as co-ligand. The corresponding aqua and hydroxido complexes also prevail in the presence of Cl– in aqueous solution. The observed FeII/III potentials in water (cyclic voltammetry) and potentials of (L1–3)FeIV=O (buffered and unbuffered aqueous solutions) are strikingly similar, i.e. the latter are assigned to (L1–3)FeII/III potentials, and published potentials of FeIV=O complexes with other ligands with uncharged amine-pyridine donors, obtained by cyclic voltammetry, have to be considered with caution.

scholarly journals The Basis of Ammonium Release in nifLMutants of Azotobacter vinelandii

1999 ◽  
Vol 181 (23) ◽  
pp. 7356-7362 ◽  
Author(s):  
Brett Brewin ◽  
Paul Woodley ◽  
Martin Drummond
Keyword(s):  
Azotobacter Vinelandii ◽  
Transcriptional Level ◽  
Uptake System ◽  
Wild Type ◽  
Two Component System ◽  
Two Component ◽  
In The Wild ◽  
Reducing Activity ◽  
State Growth ◽  
Acetylene Reducing Activity

ABSTRACT In Azotobacter vinelandii, nitrogen fixation is regulated at the transcriptional level by an unusual two-component system encoded by nifLA. Certain mutations innifL result in the bacterium releasing large quantities of ammonium into the medium, and earlier work suggested that this occurs by a mechanism that does not involve NifA, the activator ofnif gene transcription. We have investigated a number of possible alternative mechanisms and find no evidence for their involvement in ammonium release. Enhancement of NifA-mediated transcription, on the other hand, by either elimination ofnifL or overexpression of nifA, resulted in ammonium release, correlating with enhanced levels of nifHmRNA, raised levels of nitrogenase and acetylene-reducing activity, and increased concentrations of intracellular ammonium. Up to 35 mM ammonium can accumulate in the medium. Where measured, intracellular levels exceeded extracellular levels, indicating that rather than being actively transported, ammonium is lost from the cell passively, possibly by reversal of an NH4 + uptake system. The data also indicate that in the wild type the bulk of NifA is inactivated by NifL during steady-state growth on dinitrogen.

scholarly journals Hypothetical Protein Avin_16040 as the S-Layer Protein of Azotobacter vinelandii and Its Involvement in Plant Root Surface Attachment

2015 ◽  
Vol 81 (21) ◽  
pp. 7484-7495 ◽  
Author(s):  
Pauline Woan Ying Liew ◽  
Bor Chyan Jong ◽  
Nazalan Najimudin
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Azotobacter Vinelandii ◽  
Plant Root ◽  
Hypothetical Protein ◽  
Surface Hydrophobicity ◽  
Root Surface ◽  
Bacterial Cells ◽  
Wild Type ◽  
Content Type

ABSTRACTA proteomic analysis of a soil-dwelling, plant growth-promotingAzotobacter vinelandiistrain showed the presence of a protein encoded by the hypotheticalAvin_16040gene when the bacterial cells were attached to theOryza sativaroot surface. AnAvin_16040deletion mutant demonstrated reduced cellular adherence to the root surface, surface hydrophobicity, and biofilm formation compared to those of the wild type. By atomic force microscopy (AFM) analysis of the cell surface topography, the deletion mutant displayed a cell surface architectural pattern that was different from that of the wild type.Escherichia colitransformed with the wild-typeAvin_16040gene displayed on its cell surface organized motifs which looked like the S-layer monomers ofA. vinelandii. The recombinantE. colialso demonstrated enhanced adhesion to the root surface.

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