Cytochrome c nitrite reductase: from structural to physicochemical analysis

2005 ◽  
Vol 33 (1) ◽  
pp. 137-140 ◽  
Author(s):  
B. Burlat ◽  
J.D. Gwyer ◽  
S. Poock ◽  
T. Clarke ◽  
J.A. Cole ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Structural Characterization ◽  
Nitrite Reductase ◽  
Structural Features ◽  
Physicochemical Analysis ◽  
Protein Film ◽  
Protein Film Voltammetry ◽  
Cytochrome C Nitrite Reductase

The recent structural characterization of the NrfA from Escherichia coli provides a framework to rationalize the spectroscopic and functional properties of this enzyme. Analyses by EPR and magnetic CD spectroscopies have been complemented by protein-film voltammetry and these are discussed in relation to the essential structural features of the enzyme.

Inhibiting Escherichia coli cytochrome c nitrite reductase: voltammetry reveals an enzyme equipped for action despite the chemical challenges it may face in vivo

2006 ◽  
Vol 34 (1) ◽  
pp. 133-135 ◽  
Author(s):  
J.D. Gwyer ◽  
D.J. Richardson ◽  
J.N. Butt
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Large Family ◽  
Protein Film ◽  
E Coli ◽  
Protein Film Voltammetry ◽  
Cytochrome C Nitrite Reductase ◽  
Before And After

Escherichia coli cytochrome c nitrite reductase is one of a large family of homologous enzymes that are particularly prevalent in pathogenic enterobacteria. The enzymes are periplasmic and in vivo may find themselves challenged by molecules that could enhance or compromise their performance. In the present study, we describe protein film voltammetry in which the activity of E. coli cytochrome c nitrite reductase is challenged by the presence of a number of small molecules. These results are discussed in light of the environment(s) that the enzyme may face before and after colonization of a human host.

Escherichia coli Cytochrome c Nitrite Reductase NrfA

2008 ◽  
pp. 63-77 ◽  
Author(s):  
Thomas A. Clarke ◽  
Paul C. Mills ◽  
Susie R. Poock ◽  
Julea N. Butt ◽  
Myles R. Cheesman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Cytochrome C Nitrite Reductase

scholarly journals High-Resolution Structural Analysis of a Novel Octaheme Cytochrome c Nitrite Reductase from the Haloalkaliphilic Bacterium Thioalkalivibrio nitratireducens

2009 ◽  
Vol 389 (5) ◽  
pp. 846-862 ◽  
Author(s):  
Konstantin M. Polyakov ◽  
Konstantin M. Boyko ◽  
Tamara V. Tikhonova ◽  
Alvira Slutsky ◽  
Alexey N. Antipov ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Cytochrome C Nitrite Reductase

Voltammetric characterization of the aerobic energy-dissipating nitrate reductase of Paracoccus pantotrophus: exploring the activity of a redox-balancing enzyme as a function of electrochemical potential

2007 ◽  
Vol 409 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Andrew J. Gates ◽  
David J. Richardson ◽  
Julea N. Butt
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Reductase Activity ◽  
Electrochemical Potential ◽  
Intact Cells ◽  
Protein Film ◽  
Protein Film Voltammetry ◽  
Voltammetric Studies ◽  
Paracoccus Pantotrophus

Paracoccus pantotrophus expresses two nitrate reductases associated with respiratory electron transport, termed NapABC and NarGHI. Both enzymes derive electrons from ubiquinol to reduce nitrate to nitrite. However, while NarGHI harnesses the energy of the quinol/nitrate couple to generate a transmembrane proton gradient, NapABC dissipates the energy associated with these reducing equivalents. In the present paper we explore the nitrate reductase activity of purified NapAB as a function of electrochemical potential, substrate concentration and pH using protein film voltammetry. Nitrate reduction by NapAB is shown to occur at potentials below approx. 0.1 V at pH 7. These are lower potentials than required for NarGH nitrate reduction. The potentials required for Nap nitrate reduction are also likely to require ubiquinol/ubiquinone ratios higher than are needed to activate the H+-pumping oxidases expressed during aerobic growth where Nap levels are maximal. Thus the operational potentials of P. pantotrophus NapAB are consistent with a productive role in redox balancing. A Michaelis constant (KM) of approx. 45 μM was determined for NapAB nitrate reduction at pH 7. This is in line with studies on intact cells where nitrate reduction by Nap was described by a Monod constant (KS) of less than 15 μM. The voltammetric studies also disclosed maximal NapAB activity in a narrow window of potential. This behaviour is resistant to change of pH, nitrate concentration and inhibitor concentration and its possible mechanistic origins are discussed.

Purification and Characterization of a Dissimilatory Nitrite Reductase from the Phototrophic Bacterium Rhodopseudomonas palustris

1983 ◽  
Vol 38 (11-12) ◽  
pp. 933-938 ◽  
Author(s):  
Michaela Preuß ◽  
Jobst-Heinrich Klemme
Keyword(s):  
Cytochrome C ◽  
Nitrite Reductase ◽  
Rhodopseudomonas Palustris ◽  
Gel Filtration ◽  
Enzyme Synthesis ◽  
Nitrite Reduction ◽  
Phototrophic Bacterium ◽  
Dissimilatory Nitrite Reductase ◽  
Basic Level

A dissimilatory nitrite reductase from the facultatively phototrophic bacterium , Rhodopseudomonas palustris strain 1a1 was studied. A basic level of the enzyme (10 -50 mU/mg protein) was measured in dark, aerated and anaerobic, photosynthetic cultures. A marked derepression of enzyme synthesis occurred under conditions of oxygen limitation (200-300 mU/mg protein). The addition of nitrite (or nitrate) to the culture medium had only a slight effect on the maximal nitrite reductase titer of cells. The enzyme was purified from photosynthetically grown cells by precipitation with ammonium sulfate, gel filtration through Sepharose 6B and repeated chromatography on DE 52-cellulose. As estimated by gel filtration, the nitrite reductase had a molecular weight of about 120 000 ± 12 000 and yielded only one band (mol. wt. of about 68 000 ± 7000) in SDS-gel electrophoresis. The isoelectric point of the enzyme was at pH 5.1. Nitric oxide (NO) was identified as the reaction product of nitrite reduction. The enzyme also exhibited cytochrome c-oxidase activity and was active with chemically reduced viologen dyes, FMN and cytochrome c as electron donors. Highly purified nitrite reductase preparations contained 10 mol% of a c-type cytochrome. Trace metal analyses indicated the presence of Cu in the enzyme. Consistent with the detection of Cu was the finding that the Cu-chelator, diethyldithiocarbamate, strongly inhibited the nitrite reductase

Iron–sulfur repair YtfE protein from Escherichia coli: structural characterization of the di-iron center

2008 ◽  
Vol 13 (5) ◽  
pp. 765-770 ◽  
Author(s):  
Smilja Todorovic ◽  
Marta C. Justino ◽  
Gerd Wellenreuther ◽  
Peter Hildebrandt ◽  
Daniel H. Murgida ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structural Characterization ◽  
Iron Sulfur ◽  
Iron Center

scholarly journals Characterization of Borrelia burgdorferiBlyA and BlyB Proteins: a Prophage-Encoded Holin-Like System

2000 ◽  
Vol 182 (23) ◽  
pp. 6791-6797 ◽  
Author(s):  
Christopher J. Damman ◽  
Christian H. Eggers ◽  
D. Scott Samuels ◽  
Donald B. Oliver
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Activity ◽  
Soluble Protein ◽  
Structural Similarity ◽  
Structural Features ◽  
Accessory Protein ◽  
E Coli ◽  
Bacteriophage Particle ◽  
Membrane Interactive

ABSTRACT The conserved cp32 plasmid family of Borrelia burgdorferi was recently shown to be packaged into a bacteriophage particle (C. H. Eggers and D. S. Samuels, J. Bacteriol. 181:7308–7313, 1999). This plasmid encodes BlyA, a 7.4-kDa membrane-interactive protein, and BlyB, an accessory protein, which were previously proposed to comprise a hemolysis system. Our genetic and biochemical evidence suggests that this hypothesis is incorrect and that BlyA and BlyB function instead as a prophage-encoded holin or holin-like system for this newly described bacteriophage. AnEscherichia coli mutant containing the blyABlocus that was defective for the normally cryptic host hemolysin SheA was found to be nonhemolytic, suggesting that induction ofsheA by blyAB expression was responsible for the hemolytic activity observed previously. Analysis of the structural features of BlyA indicated greater structural similarity to bacteriophage-encoded holins than to hemolysins. Consistent with holin characteristics, subcellular localization studies with E. coli and B. burgdorferi indicated that BlyA is solely membrane associated and that BlyB is a soluble protein. Furthermore, BlyA exhibited a holin-like function by promoting the endolysin-dependent lysis of an induced lambda lysogen that was defective in the holin gene. Finally, induction of the cp32 prophage inB. burgdorferi dramatically stimulated blyABexpression. Our results provide the first evidence of a prophage-encoded holin within Borrelia.

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