scholarly journals Influence of Escherichia coli chaperone DnaK on protein immunogenicity

Immunology ◽  
2016 ◽  
Vol 150 (3) ◽  
pp. 343-355 ◽  
Author(s):  
Kirsty D. Ratanji ◽  
Jeremy P. Derrick ◽  
Ian Kimber ◽  
Robin Thorpe ◽  
Meenu Wadhwa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chaperone Dnak

Thermodynamic and Structural Analysis of the Folding/Unfolding Transitions of the Escherichia coli Molecular Chaperone DnaK

1993 ◽  
Vol 232 (2) ◽  
pp. 680-692 ◽  
Author(s):  
Diana Montgomery ◽  
Robert Jordan ◽  
Roger McMacken ◽  
Ernesto Freire
Keyword(s):  
Escherichia Coli ◽  
Structural Analysis ◽  
Molecular Chaperone ◽  
Chaperone Dnak

scholarly journals The DnaK Chaperone Is Necessary for α-Complementation of β-Galactosidase in Escherichia coli

2002 ◽  
Vol 184 (24) ◽  
pp. 7047-7054 ◽  
Author(s):  
Nicolas Lopes Ferreira ◽  
Jean-Hervé Alix
Keyword(s):  
Escherichia Coli ◽  
Bacterial Growth ◽  
Molecular Chaperone ◽  
Wild Type ◽  
Functional Changes ◽  
Chaperone Dnak ◽  
Ts Mutant

ABSTRACT We show here the involvement of the molecular chaperone DnaK from Escherichia coli in the in vivo α-complementation of the β-galactosidase. In the dnaK756(Ts) mutant, α-complementation occurs when the organisms are grown at 30°C but not at 37 or 40°C, although these temperatures are permissive for bacterial growth. Plasmid-driven expression of wild-type dnaK restores the α-complementation in the mutant but also stimulates it in a dnaK + strain. In a mutant which contains a disrupted dnaK gene (ΔdnaK52::Cmr), α-complementation is also impaired, even at 30°C. This observation provides an easy and original phenotype to detect subtle functional changes in a protein such as the DnaK756 chaperone, within the physiologically relevant temperature.

The Escherichia Coli. Chaperone DnaK: Properties and Potentials

1996 ◽  
pp. 311-318
Author(s):  
Sven-Olof Enfors ◽  
Kristina Gustavsson ◽  
Shaojun Yang ◽  
Andres Veide
Keyword(s):  
Escherichia Coli ◽  
Chaperone Dnak

Proline-rich Antimicrobial Peptides Optimized for Binding to Escherichia coli Chaperone DnaK

2016 ◽  
Vol 23 (12) ◽  
pp. 1061-1071 ◽  
Author(s):  
Daniel Knappe ◽  
Tina Goldbach ◽  
Marcus Hatfield ◽  
Nicholas Palermo ◽  
Stefanie Weinert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptides ◽  
Chaperone Dnak

scholarly journals Existence of Abnormal Protein Aggregates in Healthy Escherichia coli Cells

2007 ◽  
Vol 190 (3) ◽  
pp. 887-893 ◽  
Author(s):  
Etienne Maisonneuve ◽  
Laetitia Fraysse ◽  
Danielle Moinier ◽  
Sam Dukan
Keyword(s):  
Escherichia Coli ◽  
Protein Aggregates ◽  
Oxygen Species ◽  
Repair Pathway ◽  
Abnormal Protein ◽  
Virtual Absence ◽  
Escherichia Coli Cells ◽  
Chaperone Dnak ◽  
Expected Outcome ◽  
Cellular Detoxification

ABSTRACT Protein aggregation is a phenomenon observed in all organisms and has often been linked with cell disorders. In addition, several groups have reported a virtual absence of protein aggregates in healthy cells. In contrast to previous studies and the expected outcome, we observed aggregated proteins in aerobic exponentially growing and “healthy” Escherichia coli cells. We observed overrepresentation of “aberrant proteins,” as well as substrates of the major conserved chaperone DnaK (Hsp70) and the protease ClpXP (a serine protease), in the aggregates. In addition, the protein aggregates appeared to interact with chaperones known to be involved in the aggregate repair pathway, including ClpB, GroEL, GroES, and DnaK. Finally, we showed that the levels of reactive oxygen species and unfolded or misfolded proteins determine the levels of protein aggregates. Our results led us to speculate that protein aggregates may function as a temporary “trash organelle” for cellular detoxification.

scholarly journals Disruption of nucleoid expanded conformation by toxic aberrant proteins synthesized in Escherichia coli

2021 ◽  
Author(s):  
Mangala Tawde ◽  
Abdelaziz Bior ◽  
Michael Feiss ◽  
Paul Freimuth
Keyword(s):  
Escherichia Coli ◽  
Protein Quality ◽  
Bactericidal Effect ◽  
Secretory Proteins ◽  
Toxic Activity ◽  
E Coli ◽  
Open Conformation ◽  
Chaperone Dnak ◽  
Ultimate Cause ◽  
Selection Of

AbstractAminoglycoside antibiotics interfere with selection of cognate tRNAs during translation, resulting in the production of aberrant proteins that are the ultimate cause of the antibiotic bactericidal effect. To determine if these aberrant proteins are recognized as substrates by the cell’s protein quality control machinery, we studied whether the heat shock (HS) response was activated following exposure of Escherichia coli to the aminoglycoside kanamycin (Kan). Levels of the HS transcription factor σ32 increased about 10-fold after exposure to Kan, indicating that at least some aberrant proteins were recognized as substrates by the molecular chaperone DnaK. To investigate whether toxic aberrant proteins therefore might escape detection by the QC machinery, we studied model aberrant proteins that had a bactericidal effect when expressed in E. coli from cloned genes. As occurred following exposure to Kan, levels of σ32 were permanently elevated following expression of an acutely toxic 48-residue protein (ARF48), indicating that toxic activity and recognition by the QC machinery are not mutually exclusive properties of aberrant proteins, and that the HS response was blocked in these cells at some step downstream of σ32 stabilization. This block could result from halting of protein synthesis or from radial condensation of nucleoids, both of which occurred rapidly following ARF48 induction. Nucleoids were similarly condensed following expression of toxic aberrant secretory proteins, suggesting that transertion of inner membrane proteins, a process that expands nucleoids into an open conformation that promotes growth and gene expression, was disrupted in these cells. The 48-residue ARF48 protein would be well-suited for structural studies to further investigate the toxic mechanism of aberrant proteins.

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