Characterization of the interaction of dinitrogenase reductase-activating glycohydrolase from Rhodospirillum rubrum with bacterial membranes

1999 ◽  
Vol 172 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Cale M. Halbleib ◽  
P. W. Ludden
Keyword(s):  
Rhodospirillum Rubrum ◽  
Bacterial Membranes ◽  
Dinitrogenase Reductase

scholarly journals Purification and characterization of an oxygen-stable form of dinitrogenase reductase-activating glycohydrolase from Rhodospirillum rubrum

1994 ◽  
Vol 302 (3) ◽  
pp. 801-806 ◽  
Author(s):  
G M Nielsen ◽  
Y Bao ◽  
G P Roberts ◽  
P W Ludden
Keyword(s):  
Fluorescence Spectra ◽  
Rhodospirillum Rubrum ◽  
Sodium Dithionite ◽  
Stable Form ◽  
Purification And Characterization ◽  
Dinitrogenase Reductase ◽  
Bivalent Metals ◽  
Overexpressing Strain ◽  
Ribose Moiety

Dinitrogenase reductase-activating glycohydrolase (DRAG) is responsible for removing the ADP-ribose moiety from post-translationally inactivated nitrogenase of Rhodospirillum rubrum. Using DRAG purified from an overexpressing strain (UR276), further properties of this enzyme were studied, including its u.v.-visible and fluorescence spectra and its stability in air. DRAG appears to require no covalently bound inorganic cofactors for its activity or regulation. Previously, purified DRAG was found to be rapidly inactivated in air. The air-catalysed lability originated with the presence of sodium dithionite and Mn2+ throughout the purification of the enzyme. This lability can be mimicked using H2O2, which is known to oxidatively inactivate proteins containing bivalent metals. Implications for the regulation of nitrogenase are discussed with respect to the lack of sensitivity to air of the regulatory enzyme, DRAG.

scholarly journals Mutagenesis and Functional Characterization of theglnB, glnA, and nifA Genes from the Photosynthetic Bacterium Rhodospirillum rubrum

2000 ◽  
Vol 182 (4) ◽  
pp. 983-992 ◽  
Author(s):  
Yaoping Zhang ◽  
Edward L. Pohlmann ◽  
Paul W. Ludden ◽  
Gary P. Roberts
Keyword(s):  
Nitrogen Fixation ◽  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Functional Characterization ◽  
Photosynthetic Bacterium ◽  
Wild Type ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase ◽  
Adp Ribosyltransferase

ABSTRACT Nitrogen fixation is tightly regulated in Rhodospirillum rubrum at two different levels: transcriptional regulation ofnif expression and posttranslational regulation of dinitrogenase reductase by reversible ADP-ribosylation catalyzed by the DRAT-DRAG (dinitrogenase reductase ADP-ribosyltransferase–dinitrogenase reductase-activating glycohydrolase) system. We report here the characterization ofglnB, glnA, and nifA mutants and studies of their relationship to the regulation of nitrogen fixation. Two mutants which affect glnB (structural gene for PII) were constructed. While PII-Y51F showed a lower nitrogenase activity than that of wild type, a PIIdeletion mutant showed very little nif expression. This effect of PII on nif expression is apparently the result of a requirement of PII for NifA activation, whose activity is regulated by NH4 + in R. rubrum. The modification of glutamine synthetase (GS) in theseglnB mutants appears to be similar to that seen in wild type, suggesting that a paralog of PII might exist inR. rubrum and regulate the modification of GS. PII also appears to be involved in the regulation of DRAT activity, since an altered response to NH4 + was found in a mutant expressing PII-Y51F. The adenylylation of GS plays no significant role in nif expression or the ADP-ribosylation of dinitrogenase reductase, since a mutant expressing GS-Y398F showed normal nitrogenase activity and normal modification of dinitrogenase reductase in response to NH4 + and darkness treatments.

Structural Characterization of Complex Bacterial Glycolipids by Fourier Transform Mass Spectrometry

2005 ◽  
Vol 11 (5) ◽  
pp. 535-546 ◽  
Author(s):  
Anna Kondakov ◽  
Buko Lindner
Keyword(s):  
Mass Spectrometry ◽  
Fourier Transform ◽  
Structural Information ◽  
Adaptive Immune System ◽  
Ion Cyclotron Resonance ◽  
Bacterial Membranes ◽  
Multiphoton Dissociation ◽  
The One ◽  
And Function

Bacterial glycolipids are complex amphiphilic molecules which are, on the one hand, of utmost importance for the organization and function of bacterial membranes and which, on the other hand, play a major role in the activation of cells of the innate and adaptive immune system of the host. Already small alterations to their chemical structure may influence the biological activity tremendously. Due to their intrinsic biological heterogeneity [number and type of fatty acids, saccharide structures and substitution with for example, phosphate ( P), 2-aminoethyl-(pyro)phosphate groups ( P-Etn) or 4-amino-4-deoxyarabinose (Ara4N)], separation of the different components are a prerequisite for unequivocal chemical and nuclear magnetic resonance structural analyses. In this contribution, the structural information which can be obtained from heterogenous samples of glycolipids by Fourier transform (FT) ion cyclotron resonance mass spectrometric methods is described. By means of recently analysed complex biological samples, the possibilities of high-resolution electrospray ionization FT-MS are demonstrated. Capillary skimmer dissociation, as well as tandem mass spectrometry (MS/MS) analysis utilizing collision-induced dissociation and infrared multiphoton dissociation, are compared and their advantages in providing structural information of diagnostic importance are discussed.

CHARACTERIZATION OF ANTIMYCIN RESISTANT MUTANTS OF RHODOSPIRILLUM RUBRUM

1994 ◽  
Vol 22 (1) ◽  
pp. 59S-59S
Author(s):  
Joachim Uhrig ◽  
Christiane Jakobs ◽  
Christoph Majewski ◽  
Achim Trebst
Keyword(s):  
Rhodospirillum Rubrum ◽  
Resistant Mutants
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