scholarly journals Fnr Is Involved in Oxygen Control of Herbaspirillum seropedicae N-Truncated NifA Protein Activity in Escherichia coli

2003 ◽  
Vol 69 (3) ◽  
pp. 1527-1531 ◽  
Author(s):  
Rose A. Monteiro ◽  
Emanuel M. de Souza ◽  
M. Geoffrey Yates ◽  
Fabio O. Pedrosa ◽  
Leda S. Chubatsu
Keyword(s):  
Escherichia Coli ◽  
Protein A ◽  
Ammonium Ions ◽  
Oxygen Control ◽  
Herbaspirillum Seropedicae ◽  
Protein Activity ◽  
Iron Deprivation ◽  
Iron Requirement ◽  
Fnr Protein ◽  
Nifa Protein

ABSTRACT Herbaspirillum seropedicae is an endophytic diazotroph belonging to the β-subclass of the class Proteobacteria, which colonizes many members of the Gramineae. The activity of the NifA protein, a transcriptional activator of nif genes in H. seropedicae, is controlled by ammonium ions through its N-terminal domain and by oxygen through mechanisms that are not well understood. Here we report that the NifA protein of H. seropedicae is inactive and more susceptible to degradation in an fnr Escherichia coli background. Both effects correlate with oxygen exposure and iron deprivation. Our results suggest that the oxygen sensitivity and iron requirement for H. seropedicae NifA activity involve the Fnr protein.

Use of lactose to induce expression of soluble NifA protein domains of Herbaspirillum seropedicae in Escherichia coli

2000 ◽  
Vol 46 (11) ◽  
pp. 1087-1090 ◽  
Author(s):  
Rose A. Monteiro ◽  
Emanuel M. Souza ◽  
M. Geoffrey Yates ◽  
Fábio O. Pedrosa ◽  
Leda S. Chubatsu
Keyword(s):  
Escherichia Coli ◽  
Protein Domains ◽  
Herbaspirillum Seropedicae ◽  
Nifa Protein

Use of lactose to induce expression of soluble NifA protein domains ofHerbaspirillum seropedicaeinEscherichia coli

2000 ◽  
Vol 46 (11) ◽  
pp. 1087-1090 ◽  
Author(s):  
Rose A Monteiro ◽  
Emanuel M Souza ◽  
M Geoffrey Yates ◽  
Fábio O Pedrosa ◽  
Leda S Chubatsu
Keyword(s):  
Escherichia Coli ◽  
Soluble Fraction ◽  
Herbaspirillum Seropedicae ◽  
Enhancer Binding Protein ◽  
Nifa Protein ◽  
Kinetics Of ◽  
Background Expression ◽  
Fix Genes

Overexpression and purification are procedures used to allow functional and structural characterization of proteins. Many overexpressed proteins are partially or completely insoluble, and can not be easily purified. The NifA protein is an enhancer-binding protein involved in activating the expression of nif and some fix genes. The NifA protein from many organisms is usually insoluble when over-expressed, and therefore difficult to work with in vitro. In this work we have overexpressed the central+C-terminal and the central domains of the Herbaspirrilum seropedicae NifA protein in an Escherichia coli background. Expression was induced with either IPTG or lactose. The data showed that induction with lactose promoted a significantly higher percentage of these proteins in the soluble fraction than with IPTG. This probably reflects a slower kinetics of induction by lactose.Key words: Herbaspirillum seropedicae, NifA protein, transcriptional activator, nitrogen fixation, protein expression.

Overexpression of Outer Membrane Protein A Is a Risk Factor for Mortality in Escherichia coli Bloodstream Infections

2019 ◽  
Author(s):  
Ángel Rodríguez-Villodres ◽  
Rocío Álvarez-Marín ◽  
María Antonia Pérez-Moreno ◽  
Andrea Miró-Canturri ◽  
Marco Durán Lobato ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Risk Factor ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein A ◽  
Bloodstream Infections ◽  
Outer Membrane Protein A

scholarly journals Recombinant outer membrane protein A fragments protect against Escherichia coli meningitis

2016 ◽  
Vol 49 (3) ◽  
pp. 329-334 ◽  
Author(s):  
Wen-Shyang Hsieh ◽  
Yi-Yuan Yang ◽  
Hsin-Yi Yang ◽  
Yu-Shan Huang ◽  
Hsueh-Hsia Wu
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein A ◽  
Outer Membrane Protein A

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Polymerase Chain Reaction Amplification ◽  
Protein A ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Gene Encoding ◽  
Reaction Amplification ◽  
Mutant Genes

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.

scholarly journals Cytotoxic Efficacy and Resistance Mechanism of a TRAIL and VEGFA-Peptide Fusion Protein in Colorectal Cancer Models

2021 ◽  
Vol 22 (6) ◽  
pp. 3160
Author(s):  
Michal Kopczynski ◽  
Malgorzata Statkiewicz ◽  
Magdalena Cybulska ◽  
Urszula Kuklinska ◽  
Katarzyna Unrug-Bielawska ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Lines ◽  
Transmembrane Protein ◽  
Acquired Resistance ◽  
Protein A ◽  
Resistance Mechanism ◽  
Receptor Expression ◽  
Human Colorectal Cancer ◽  
Protein Activity ◽  
Anticancer Efficacy

TNF-related apoptosis-inducing ligand (TRAIL) is a type II transmembrane protein capable of selectively inducing apoptosis in cancer cells by binding to its cognate receptors. Here, we examined the anticancer efficacy of a recently developed chimeric AD-O51.4 protein, a TRAIL fused to the VEGFA-originating peptide. We tested AD-O51.4 protein activity against human colorectal cancer (CRC) models and investigated the resistance mechanism in the non-responsive CRC models. The quantitative comparison of apoptotic activity between AD-O51.4 and the native TRAIL in nine human colorectal cancer cell lines revealed dose-dependent toxicity in seven of them; the immunofluorescence-captured receptor abundance correlated with the extent of apoptosis. AD-O51.4 reduced the growth of CRC patient-derived xenografts (PDXs) with good efficacy. Cell lines that acquired AD-O51.4 resistance showed a significant decrease in surface TRAIL receptor expression and apoptosis-related proteins, including Caspase-8, HSP60, and p53. These results demonstrate the effectiveness of AD-O51.4 protein in CRC preclinical models and identify the potential mechanism underlying acquired resistance. Progression of AD-O51.4 to clinical trials is expected.

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