scholarly journals The Growth-Promoting and Stress Response Activities of the Bacillus subtilis GTP Binding Protein Obg Are Separable by Mutation

2008 ◽  
Vol 190 (20) ◽  
pp. 6625-6635 ◽  
Author(s):  
Shrin Kuo ◽  
Borries Demeler ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Amino Acid ◽  
Binding Protein ◽  
Normal Growth ◽  
Gtp Binding Protein ◽  
Missense Change ◽  
Gtp Binding ◽  
Growth Promoting ◽  
Carboxy Terminal

ABSTRACT Bacillus subtilis Obg is a ribosome-associating GTP binding protein that is needed for growth, sporulation, and induction of the bacterium's general stress regulon (GSR). It is unclear whether the roles of Obg in sporulation and stress responsiveness are direct or a secondary effect of its growth-promoting functions. The present work addresses this question by an analysis of two obg alleles whose phenotypes argue for direct roles for Obg in each process. The first allele [obg(G92D)] encodes a missense change in the protein's highly conserved “obg fold” region. This mutation impairs cell growth and the ability of Obg to associate with ribosomes but fails to block sporulation or the induction of the GSR. The second obg mutation [obg(Δ22)] replaces the 22-amino-acid carboxy-terminal sequence of Obg with an alternative 26-amino-acid sequence. This Obg variant cofractionates with ribosomes and allows normal growth but blocks sporulation and impairs the induction of the GSR. Additional experiments revealed that the block on sporulation occurs early, preventing the activation of the essential sporulation transcription factor Spo0A, while inhibition of the GSR appears to involve a failure of the protein cascade that normally activates the GSR to effectively catalyze the reactions needed to activate the GSR transcription factor (σB).

scholarly journals The Bacillus subtilis GTP Binding Protein Obg and Regulators of the ςB Stress Response Transcription Factor Cofractionate with Ribosomes

2000 ◽  
Vol 182 (10) ◽  
pp. 2771-2777 ◽  
Author(s):  
Janelle M. Scott ◽  
Jingliang Ju ◽  
Theresa Mitchell ◽  
W. G. Haldenwang
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Fluorescent Microscopy ◽  
Gel Filtration ◽  
Gtp Binding Protein ◽  
Ribosomal Subunits ◽  
Gtp Binding ◽  
Stress Activation

ABSTRACT Obg, an essential GTP binding protein of Bacillus subtilis, is necessary for stress activation of the ςB transcription factor. We investigated Obg's cellular associations by differential centrifugation of crude B. subtilis extracts, using an anti-Obg antibody as a probe to monitor Obg during the fractionation, and by fluorescent microscopy of a B. subtilis strain in which Obg was fused to green fluorescent protein. The results indicated that Obg is part of a large cytoplasmic complex. In subsequent analyses, Obg coeluted with ribosomal subunits during gel filtration of B. subtilislysates on Sephacryl S-400 and specifically bound to ribosomal protein L13 in an affinity blot assay. Probing the gel filtration fractions with antibodies specific for ςB and its coexpressed regulators (Rsb proteins) revealed coincident elution of the upstream components of the ςB stress activation pathway (RsbR, -S, and -T) with Obg and the ribosomal subunits. The data implicate ribosome function as a possible mediator of the activity of Obg and the stress induction of ςB.

Molecular cloning and characterization of a novel type of regulatory protein (GDI) for smg p25A, a ras p21-like GTP-binding protein

1990 ◽  
Vol 10 (8) ◽  
pp. 4116-4122
Author(s):  
Y Matsui ◽  
A Kikuchi ◽  
S Araki ◽  
Y Hata ◽  
J Kondo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Exchange Reaction ◽  
Binding Protein ◽  
Regulatory Protein ◽  
Bovine Brain ◽  
Subunit Structure ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Ras P21

We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the beta gamma subunits of GTP-binding proteins having an alpha beta gamma subunit structure, such as Gs and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent.

scholarly journals Molecular cloning and characterization of a novel type of regulatory protein (GDI) for smg p25A, a ras p21-like GTP-binding protein.

1990 ◽  
Vol 10 (8) ◽  
pp. 4116-4122 ◽  
Author(s):  
Y Matsui ◽  
A Kikuchi ◽  
S Araki ◽  
Y Hata ◽  
J Kondo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Exchange Reaction ◽  
Binding Protein ◽  
Regulatory Protein ◽  
Bovine Brain ◽  
Subunit Structure ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Ras P21

We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the beta gamma subunits of GTP-binding proteins having an alpha beta gamma subunit structure, such as Gs and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent.

Purification and Partial Amino Acid Sequences of a Phospholipase CAssociated GTP-Binding Protein from Calf Thymocytes1

1989 ◽  
Vol 105 (3) ◽  
pp. 461-466 ◽  
Author(s):  
Peng Wang ◽  
Jun Nishihata ◽  
Eiji Takabori ◽  
Kazuo Yamamoto ◽  
Satoshi Toyoshima ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Protein ◽  
Amino Acid Sequences ◽  
Gtp Binding Protein ◽  
Gtp Binding

Analysis of the Open and Closed Conformations of the GTP-binding Protein YsxC from Bacillus subtilis

2004 ◽  
Vol 339 (2) ◽  
pp. 265-278 ◽  
Author(s):  
Sergey N. Ruzheinikov ◽  
Sanjan K. Das ◽  
Svetlana E. Sedelnikova ◽  
Patrick J. Baker ◽  
Peter J. Artymiuk ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Binding Protein ◽  
Gtp Binding Protein ◽  
Gtp Binding
Sign in / Sign up

Export Citation Format

Share Document