scholarly journals Roles of the Escherichia coli Small Heat Shock Proteins IbpA and IbpB in Thermal Stress Management: Comparison with ClpA, ClpB, and HtpG In Vivo

1998 ◽  
Vol 180 (19) ◽  
pp. 5165-5172 ◽  
Author(s):  
Jeffrey G. Thomas ◽  
François Baneyx
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
High Temperatures ◽  
Small Heat Shock Proteins ◽  
Host Protein ◽  
E Coli ◽  
Growth Defects ◽  
Shock Proteins

ABSTRACT We have constructed an Escherichia coli strain lacking the small heat shock proteins IbpA and IbpB and compared its growth and viability at high temperatures to those of isogenic cells containing null mutations in the clpA, clpB, orhtpG gene. All mutants exhibited growth defects at 46°C, but not at lower temperatures. However, the clpA,htpG, and ibp null mutations did not reduce cell viability at 50°C. When cultures were allowed to recover from transient exposure to 50°C, all mutations except Δibpled to suboptimal growth as the recovery temperature was raised. Deletion of the heat shock genes clpB and htpGresulted in growth defects at 42°C when combined with thednaK756 or groES30 alleles, while the Δibp mutation had a detrimental effect only on the growth of dnaK756 mutants. Neither the overexpression of these heat shock proteins nor that of ClpA could restore the growth ofdnaK756 or groES30 cells at high temperatures. Whereas increased levels of host protein aggregation were observed indnaK756 and groES30 mutants at 46°C compared to wild-type cells, none of the null mutations had a similar effect. These results show that the highly conserved E. coli small heat shock proteins are dispensable and that their deletion results in only modest effects on growth and viability at high temperatures. Our data also suggest that ClpB, HtpG, and IbpA and -B cooperate with the major E. coli chaperone systems in vivo.

scholarly journals The Escherichia coli small heat-shock proteins IbpA and IbpB prevent the aggregation of endogenous proteins denatured in vivo during extreme heat shock

Microbiology ◽  
2002 ◽  
Vol 148 (6) ◽  
pp. 1757-1765 ◽  
Author(s):  
Dorota Kuczynska-Wisnik ◽  
Sabina Kçdzierska ◽  
Ewelina Matuszewska ◽  
Peter Lund ◽  
Alina Taylor ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
Extreme Heat ◽  
Endogenous Proteins ◽  
Shock Proteins

In Vitro Holdase Activity of E. coli Small Heat-Shock Proteins IbpA, IbpB and IbpAB: A Biophysical Study with Some Unconventional Techniques

2014 ◽  
Vol 21 (6) ◽  
pp. 564-571 ◽  
Author(s):  
Sourav Roy ◽  
Monobesh Patra ◽  
Suman Nandy ◽  
Milon Banik ◽  
Rakhi Dasgupta ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
E Coli ◽  
Biophysical Study ◽  
Shock Proteins

The Small Heat-shock Proteins IbpA and IbpB in E. coli: The Small Ones With a Big Role

2016 ◽  
Vol 9 (2) ◽  
pp. 84-96
Author(s):  
Sanchari Bhattacharjee ◽  
Rakhi Dasgupta ◽  
Angshuman Bagchi
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
E Coli ◽  
Shock Proteins

scholarly journals Functional Analysis of Genes Comprising the Locus of Heat Resistance in Escherichia coli

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
Ryan Mercer ◽  
Oanh Nguyen ◽  
Qixing Ou ◽  
Lynn McMullen ◽  
Michael G. Gänzle
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Resistance ◽  
Growth Phase ◽  
Genomic Island ◽  
Enteric Bacteria ◽  
Content Type ◽  
E Coli ◽  
Shock Proteins

ABSTRACT The locus of heat resistance (LHR) is a 15- to 19-kb genomic island conferring exceptional heat resistance to organisms in the family Enterobacteriaceae, including pathogenic strains of Salmonella enterica and Escherichia coli. The complement of LHR-comprising genes that is necessary for heat resistance and the stress-induced or growth-phase-induced expression of LHR-comprising genes are unknown. This study determined the contribution of the seven LHR-comprising genes yfdX1 GI, yfdX2, hdeD GI, orf11, trx GI, kefB, and psiE GI by comparing the heat resistances of E. coli strains harboring plasmid-encoded derivatives of the different LHRs in these genes. (Genes carry a subscript “GI” [genomic island] if an ortholog of the same gene is present in genomes of E. coli.) LHR-encoded heat shock proteins sHSP20, ClpKGI, and sHSPGI are not sufficient for the heat resistance phenotype; YfdX1, YfdX2, and HdeD are necessary to complement the LHR heat shock proteins and to impart a high level of resistance. Deletion of trx GI, kefB, and psiE GI from plasmid-encoded copies of the LHR did not significantly affect heat resistance. The effect of the growth phase and the NaCl concentration on expression from the putative LHR promoter p2 was determined by quantitative reverse transcription-PCR and by a plasmid-encoded p2:GFP promoter fusion. The expression levels of exponential- and stationary-phase E. coli cells were not significantly different, but the addition of 1% NaCl significantly increased LHR expression. Remarkably, LHR expression in E. coli was dependent on a chromosomal copy of evgA. In conclusion, this study improved our understanding of the genes required for exceptional heat resistance in E. coli and factors that increase their expression in food. IMPORTANCE The locus of heat resistance (LHR) is a genomic island conferring exceptional heat resistance to several foodborne pathogens. The exceptional level of heat resistance provided by the LHR questions the control of pathogens by current food processing and preparation techniques. The function of LHR-comprising genes and their regulation, however, remain largely unknown. This study defines a core complement of LHR-encoded proteins that are necessary for heat resistance and demonstrates that regulation of the LHR in E. coli requires a chromosomal copy of the gene encoding EvgA. This study provides insight into the function of a transmissible genomic island that allows otherwise heat-sensitive enteric bacteria, including pathogens, to lead a thermoduric lifestyle and thus contributes to the detection and control of heat-resistant enteric bacteria in food.

In vivo evidence from an Agrostis stolonifera selection genotype that chloroplast small heat-shock proteins can protect photosystem II during heat stress

2002 ◽  
Vol 29 (8) ◽  
pp. 935 ◽  
Author(s):  
Scott A. Heckathorn ◽  
Samantha L. Ryan ◽  
Joanne A. Baylis ◽  
Dongfang Wang ◽  
E. William Hamilton III ◽  
...  
Keyword(s):  
Heat Stress ◽  
Electron Transport ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Agrostis Stolonifera ◽  
Small Heat Shock Proteins ◽  
O2 Evolution ◽  
Shock Proteins ◽  
Tolerant Genotype

Previous in vitro experiments indicated that chloroplast small heat-shock proteins (sHsp) could associate with thylakoids and protect PSII during heat and other stresses, possibly by stabilizing the O2-evolving complex (OEC). However, in vivo evidence of sHsp protection of PSII is equivocal at present. Using previously characterized selection genotypes of Agrostis stolonifera Huds. that differ in thermotolerance and production of chloroplast sHsps, we show that both genotypes contain thylakoid-associating sHsps, but the heat-tolerant genotype, which produces an additional sHsp isoform not made by the sensitive genotype, produces a greater quantity of chloroplast and thylakoid sHsp. Following a pre-heat stress to induce sHsps, in vivo PSII function decreased less at high temperatures in the tolerant genotype. Differences in PSII thermotolerance in vivo were associated with increased thermotolerance of the OEC proteins and O2-evolving function of PSII, and not with other PSII proteins or functions examined. In vivo cross-linking experiments indicated that a greater amount of sHsp associated with PSII proteins during heat stress in the tolerant genotype. PSII was the most thermosensitive component of photosynthetic electron transport, and no differences between genotypes in the thermotolerance of other electron transport components were observed. These results indicate that in vivo chloroplast sHsps can protect O2 evolution and the OEC proteins of PSII during heat stress.

scholarly journals Comparative analysis of the molecular mechanism of heat shock proteins from pathogenic and non-pathogenic E.coli

2020 ◽  
Author(s):  
Sanchari Bhattacharjee ◽  
Mohana Saha ◽  
Rakhi Dasgupta ◽  
Angshuman Bagchi
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Temperature Stress ◽  
Small Heat Shock Proteins ◽  
Lon Protease ◽  
E Coli ◽  
Physiological Temperature ◽  
Mechanism Of Interaction ◽  
Shock Proteins ◽  
Catalytic Dyad

AbstractCells can withstand the effects of temperature stress by activating small heat shock proteins IbpA and IbpB. Lon protease employing Ser679 – Lys722 catalytic dyad proteolyze IbpA and IbpB in their free forms, at physiological temperature i.e. without any temperature stress. However, the proteolytic activity of IbpA and IbpB is affected when the catalytic dyad residue of Lon protease is mutated. The mutation S679A in Lon protease brings about some changes so that the proteolytic interactions between the small heat shock proteins with that of the mutant Lon protease are lost which makes a difference in the interaction pattern of mutant Lon protease with their substrates. In the present study, we made an attempt through in-silico approach to figure out the underlying aspects of the interactions between the small heat shock proteins IbpA and IbpB with mutant Lon protease in Escherichia coli. We have tried to decipher the molecular details of the mechanism of interaction of proteolytic machinery of small heat shock proteins and mutant Lon protease with S679A mutation at physiological temperature in absence cellular temperature stress. Our study may therefore be helpful to decode the mechanistic details of the correlation with IbpA, IbpB and S679A mutant Lon protease in E. coli.

scholarly journals Heat Shock Protein-Mediated Resistance to High Hydrostatic Pressure in Escherichia coli

2004 ◽  
Vol 70 (5) ◽  
pp. 2660-2666 ◽  
Author(s):  
Abram Aertsen ◽  
Kristof Vanoirbeek ◽  
Philipp De Spiegeleer ◽  
Jan Sermon ◽  
Kristel Hauben ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
High Hydrostatic Pressure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
E Coli ◽  
Shock Proteins

ABSTRACT A random library of Escherichia coli MG1655 genomic fragments fused to a promoterless green fluorescent protein (GFP) gene was constructed and screened by differential fluorescence induction for promoters that are induced after exposure to a sublethal high hydrostatic pressure stress. This screening yielded three promoters of genes belonging to the heat shock regulon (dnaK, lon, clpPX), suggesting a role for heat shock proteins in protection against, and/or repair of, damage caused by high pressure. Several further observations provide additional support for this hypothesis: (i) the expression of rpoH, encoding the heat shock-specific sigma factor σ32, was also induced by high pressure; (ii) heat shock rendered E. coli significantly more resistant to subsequent high-pressure inactivation, and this heat shock-induced pressure resistance followed the same time course as the induction of heat shock genes; (iii) basal expression levels of GFP from heat shock promoters, and expression of several heat shock proteins as determined by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins extracted from pulse-labeled cells, was increased in three previously isolated pressure-resistant mutants of E. coli compared to wild-type levels.

scholarly journals Multiple layers of control govern expression of the Escherichia coli ibpAB heat-shock operon

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Lena C. Gaubig ◽  
Torsten Waldminghaus ◽  
Franz Narberhaus
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Transcriptional Control ◽  
Rnase E ◽  
Translation Control ◽  
E Coli ◽  
Complex Process ◽  
Shock Proteins

The Escherichia coli ibpAB operon encodes two small heat-shock proteins, the inclusion-body-binding proteins IbpA and IbpB. Here, we report that expression of ibpAB is a complex process involving at least four different layers of control, namely transcriptional control, RNA processing, translation control and protein stability. As a typical member of the heat-shock regulon, transcription of the ibpAB operon is controlled by the alternative sigma factor σ 32 (RpoH). Heat-induced transcription of the bicistronic operon is followed by RNase E-mediated processing events, resulting in monocistronic ibpA and ibpB transcripts and short 3′-terminal ibpB fragments. Translation of ibpA is controlled by an RNA thermometer in its 5′ untranslated region, forming a secondary structure that blocks entry of the ribosome at low temperatures. A similar structure upstream of ibpB is functional in vitro but not in vivo, suggesting downregulation of ibpB expression in the presence of IbpA. The recently reported degradation of IbpA and IbpB by the Lon protease and differential regulation of IbpA and IbpB levels in E. coli are discussed.

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