scholarly journals Glycine 100 in the dinitrogenase reductase of Rhodospirillum rubrum is required for nitrogen fixation but not for ADP-ribosylation.

1991 ◽  
Vol 173 (19) ◽  
pp. 6159-6161 ◽  
Author(s):  
L J Lehman ◽  
G P Roberts
Keyword(s):  
Nitrogen Fixation ◽  
Rhodospirillum Rubrum ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase

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.

Metabolic regulation of nitrogen fixation in Rhodospirillum rubrum

2006 ◽  
Vol 34 (1) ◽  
pp. 160-161 ◽  
Author(s):  
H. Wang ◽  
A. Norén
Keyword(s):  
Nitrogen Fixation ◽  
Metabolic Regulation ◽  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Nitrogen Concentration ◽  
Sudden Increase ◽  
Fixed Nitrogen ◽  
Energy Depletion ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase

Nitrogenase activity in Rhodospirillum rubrum is post-translationally regulated by DRAG (dinitrogenase reductase glycohydrolase) and DRAT (dinitrogenase reductase ADP-ribosylation transferase). When a sudden increase in fixed nitrogen concentration or energy depletion is sensed by the cells, DRAG is inactivated and DRAT activated. We propose that the regulation of DRAG is dependent on its location in the cell and the presence of an ammonium-sensing protein.

scholarly journals Correlation of Activity Regulation and Substrate Recognition of the ADP-Ribosyltransferase That Regulates Nitrogenase Activity in Rhodospirillum rubrum

1999 ◽  
Vol 181 (5) ◽  
pp. 1698-1702 ◽  
Author(s):  
Kitai Kim ◽  
Yaoping Zhang ◽  
Gary P. Roberts
Keyword(s):  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Substrate Recognition ◽  
Posttranslational Regulation ◽  
Activity Regulation ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase ◽  
Adp Ribosyltransferase

ABSTRACT In Rhodospirillum rubrum, nitrogenase activity is regulated posttranslationally through the ADP-ribosylation of dinitrogenase reductase by dinitrogenase reductase ADP-ribosyltransferase (DRAT). Several DRAT variants that are altered both in the posttranslational regulation of DRAT activity and in the ability to recognize variants of dinitrogenase reductase have been found. This correlation suggests that these two properties are biochemically connected.

scholarly journals Role of the Dinitrogenase Reductase Arginine 101 Residue in Dinitrogenase Reductase ADP-Ribosyltransferase Binding, NAD Binding, and Cleavage

2001 ◽  
Vol 183 (1) ◽  
pp. 250-256 ◽  
Author(s):  
Yan Ma ◽  
Paul W. Ludden
Keyword(s):  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase ◽  
Adp Ribosyltransferase

ABSTRACT Dinitrogenase reductase is posttranslationally regulated by dinitrogenase reductase ADP-ribosyltransferase (DRAT) via ADP-ribosylation of the arginine 101 residue in some bacteria.Rhodospirillum rubrum strains in which the arginine 101 of dinitrogenase reductase was replaced by tyrosine, phenylalanine, or leucine were constructed by site-directed mutagenesis of thenifH gene. The strain containing the R101F form of dinitrogenase reductase retains 91%, the strain containing the R101Y form retains 72%, and the strain containing the R101L form retains only 28% of in vivo nitrogenase activity of the strain containing the dinitrogenase reductase with arginine at position 101. In vivo acetylene reduction assays, immunoblotting with anti-dinitrogenase reductase antibody, and [adenylate-32P]NAD labeling experiments showed that no switch-off of nitrogenase activity occurred in any of the three mutants and no ADP-ribosylation of altered dinitrogenase reductases occurred either in vivo or in vitro. Altered dinitrogenase reductases from strains UR629 (R101Y) and UR630 (R101F) were purified to homogeneity. The R101F and R101Y forms of dinitrogenase reductase were able to form a complex with DRAT that could be chemically cross-linked by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide. The R101F form of dinitrogenase reductase and DRAT together were not able to cleave NAD. This suggests that arginine 101 is not critical for the binding of DRAT to dinitrogenase reductase but that the availability of arginine 101 is important for NAD cleavage. Both DRAT and dinitrogenase reductase can be labeled by [carbonyl-14C]NAD individually upon UV irradiation, but most 14C label is incorporated into DRAT when both proteins are present. The ability of R101F dinitrogenase reductase to be labeled by [carbonyl-14C]NAD suggested that Arg 101 is not absolutely required for NAD binding.

scholarly journals Ammonia Switch-Off of Nitrogen Fixation in the Methanogenic Archaeon Methanococcus maripaludis: Mechanistic Features and Requirement for the Novel GlnB Homologues, NifI1 and NifI2

2001 ◽  
Vol 183 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Peter S. Kessler ◽  
Catherine Daniel ◽  
John A. Leigh
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Covalent Modification ◽  
The Novel ◽  
Methanococcus Maripaludis ◽  
Adp Ribosylation ◽  
Physiological Importance ◽  
Dinitrogenase Reductase ◽  
Reversible Covalent ◽  
Short Time

ABSTRACT Ammonia switch-off is the immediate inactivation of nitrogen fixation that occurs when a superior nitrogen source is encountered. In certain bacteria switch-off occurs by reversible covalent ADP-ribosylation of the dinitrogenase reductase protein, NifH. Ammonia switch-off occurs in diazotrophic species of the methanogenicArchaea as well. We showed previously that inMethanococcus maripaludis switch-off requires at least one of two novel homologues of glnB, a family of genes whose products play a central role in nitrogen sensing and regulation in bacteria. The novel glnB homologues have recently been named nifI 1 and nifI 2. Here we use in-frame deletions and genetic complementation analysis inM. maripaludis to show that thenifI 1 and nifI 2 genes are both required for switch-off. We could not detect ADP-ribosylation or any other covalent modification of dinitrogenase reductase during switch-off, suggesting that the mechanism differs from the well-studied bacterial system. Furthermore, switch-off did not affectnif gene transcription, nifH mRNA stability, or NifH protein stability. Nitrogenase activity resumed within a short time after ammonia was removed from a switched-off culture, suggesting that whatever the mechanism, it is reversible. We demonstrate the physiological importance of switch-off by showing that it allows growth to accelerate substantially when a diazotrophic culture is switched to ammonia.

Genes coding for the reversible ADP-ribosylation system of dinitrogenase reductase from Rhodospirillum rubrum

1989 ◽  
Vol 218 (2) ◽  
pp. 340-347 ◽  
Author(s):  
Wayne P. Fitzmaurice ◽  
Leonard L. Saari ◽  
Robert G. Lowery ◽  
Paul W. Ludden ◽  
Gary P. Roberts
Keyword(s):  
Rhodospirillum Rubrum ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase

scholarly journals Effect of PII and Its Homolog GlnK on Reversible ADP-Ribosylation of Dinitrogenase Reductase by Heterologous Expression of the Rhodospirillum rubrum Dinitrogenase Reductase ADP-Ribosyl Transferase–Dinitrogenase Reductase-Activating Glycohydrolase Regulatory System inKlebsiella pneumoniae

2001 ◽  
Vol 183 (5) ◽  
pp. 1610-1620 ◽  
Author(s):  
Yaoping Zhang ◽  
Edward L. Pohlmann ◽  
Cale M. Halbleib ◽  
Paul W. Ludden ◽  
Gary P. Roberts
Keyword(s):  
Klebsiella Pneumoniae ◽  
Heterologous Expression ◽  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Expression System ◽  
Regulatory System ◽  
Wild Type ◽  
Heterologous Expression System ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase

ABSTRACT Reversible ADP-ribosylation of dinitrogenase reductase, catalyzed by the dinitrogenase reductase ADP-ribosyl transferase–dinitrogenase reductase-activating glycohydrolase (DRAT-DRAG) regulatory system, has been characterized in Rhodospirillum rubrum and other nitrogen-fixing bacteria. To investigate the mechanisms for the regulation of DRAT and DRAG activities, we studied the heterologous expression of R. rubrum draTG in Klebsiella pneumoniae glnB and glnK mutants. In K. pneumoniae wild type, the regulation of both DRAT and DRAG activity appears to be comparable to that seen in R. rubrum. However, the regulation of both DRAT and DRAG activities is altered in a glnB background. Some DRAT escapes regulation and becomes active under N-limiting conditions. The regulation of DRAG activity is also altered in a glnBmutant, with DRAG being inactivated more slowly in response to NH4 + treatment than is seen in wild type, resulting in a high residual nitrogenase activity. In aglnK background, the regulation of DRAT activity is similar to that seen in wild type. However, the regulation of DRAG activity is completely abolished in the glnK mutant; DRAG remains active even after NH4 + addition, so there is no loss of nitrogenase activity. The results with this heterologous expression system have implications for DRAT-DRAG regulation inR. rubrum.

scholarly journals ADP-ribosylation of dinitrogenase reductase from Clostridium pasteurianum prevents its inhibition of nitrogenase from Azotobacter vinelandii

1988 ◽  
Vol 251 (2) ◽  
pp. 609-612 ◽  
Author(s):  
S A Murrell ◽  
R G Lowery ◽  
P W Ludden
Keyword(s):  
Rhodospirillum Rubrum ◽  
Azotobacter Vinelandii ◽  
Clostridium Pasteurianum ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase ◽  
Adp Ribosyltransferase

The effect of ADP-ribosylation of dinitrogenase reductase on its binding to dinitrogenase was investigated. Dinitrogenase reductase from Clostridium pasteurianum (Cp2) was a substrate for the ADP-ribosyltransferase and the dinitrogenase-reductase-activating glycohydrolase from Rhodospirillum rubrum. ADP-ribosylation inactivated Cp2 and prevented its formation of a tight complex with dinitrogenase from Azotobacter vinelandii (Av1). The complex between Cp2 and Av1 could not be ADP-ribosylated once it formed.

Reversible ADP-Ribosylation of Dinitrogenase Reductase from Rhodospirillum rubrum Regulates the Activity of the Enzyme In Vivo and In Vitro

1989 ◽  
pp. 18-25
Author(s):  
Paul W. Ludden ◽  
Scott A. Murrell ◽  
Robert G. Lowery ◽  
Wayne P. Fitzmaurice ◽  
Mark R. Pope ◽  
...  
Keyword(s):  
Rhodospirillum Rubrum ◽  
Adp Ribosylation ◽  
Dinitrogenase Reductase
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