scholarly journals Formation in vitro of complexes between an abnormal fusion protein and the heat shock proteins from Escherichia coli and yeast mitochondria.

1991 ◽  
Vol 173 (22) ◽  
pp. 7249-7256 ◽  
Author(s):  
M Y Sherman ◽  
A L Goldberg
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Fusion Protein ◽  
Yeast Mitochondria ◽  
Shock Proteins

The Escherichia coli chaperones involved in DNA replicadon

1993 ◽  
Vol 339 (1289) ◽  
pp. 271-278 ◽  
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Conformational Changes ◽  
Heat Shock Genes ◽  
Dnab Helicase ◽  
Initiation Of Dna Replication ◽  
Shock Proteins

Mutadons in the Escherichia coli heat shock genes, dnaK , dnaJ or grpE , alter host DNA and RNA synthesis, degradation of other proteins, cell division and expression of other heat shock genes. They also block the initiation of DNA replication of bacteriophages λ and P1, and the mini-F plasmid. An in vitro λDNA replication system, composed entirely of purified components, enabled us to describe the molecular mechanism of the dnaK , dnaJ and grpE gene products. DnaK , the bacterial hsp 70 homologue, releases λP protein from the preprimosomal complex in an ATP- and DnaJ-dependent reaction (GrpEindependent initiation of λDNA replication). In this paper, I show that, when GrpE is present, λP protein is not released from the preprimosomal complex, rather it is translocated within the complex in such a way that it does not inhibit DnaB helicase activity. Translocation of λP triggers the initiation event allowing DnaB helicase to unwind DNA near the ori λ sequence, leading to efficient λDNA replication. Chaperone activity of the DnaK -DnaJ-GrpE system is first manifested in the selective binding of these heat shock proteins to the preprimosomal complex, followed by its ATP-dependent rearrangement. I show that DnaJ not only tags the preprimosomal complex for recognition by DnaK, but also stabilizes the multi-protein structure. GrpE also participates in the binding of DnaK to the preprimosomal complex by increasing DnaK ’s affinity to those λP proteins which are already associated with DnaJ. After attracting DnaK to the preprimosomal complex, DnaJ and GrpE stimulate the ATPase activity of DnaK , triggering conformational changes in DnaK which are responsible for the rearrangement of proteins in the preprimosomal complex and recycling of these heat shock proteins. The role of DnaK , DnaJ and GrpE in λDNA replication is in sharp contrast to our understanding of their role in the oriC , P1, and probably mini-F DNA replication systems. In the cases of oriC and P1 DNA replication, these heat shock proteins activate initiation factors before they are in contact with DNA, and are not required during the subsequent steps leading to the initiation of DNA replication. The common feature of DnaK , DnaJ and GrpE action in these systems is their ATP-dependent disaggregation or rearrangement of protein complexes formed before or during initiation of DNA replication.

scholarly journals TNF- , IL-1 , IL-6 and ICAM-1 Expression in Human Keratinocytes Stimulated in Vitro with Escherichia Coli Heat-Shock Proteins

Microbiology ◽  
1997 ◽  
Vol 143 (1) ◽  
pp. 45-53 ◽  
Author(s):  
A. Marcatili ◽  
G. C. de I'Ero ◽  
M. Galdiero ◽  
A. Folgore ◽  
G. Petrillo
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Human Keratinocytes ◽  
Shock Proteins

Thermoprotective properties of small heat shock proteins from rice, tomato and Synechocystis sp. PCC6803 overexpressed in, and isolated from, Escherichia coli

2001 ◽  
Vol 28 (12) ◽  
pp. 1219
Author(s):  
Carl S. Pike ◽  
Joanne Grieve ◽  
Murray R. Badger ◽  
G. Dean Price
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Photosystem Ii ◽  
Heat Shock Proteins ◽  
Thermal Aggregation ◽  
E Coli ◽  
Synechococcus Sp ◽  
Shock Proteins ◽  
Synechocystis Sp

The present study forms part of a program investigating the role of small heat shock proteins (sHSPs) in the acquired and transgenic thermotolerance of the cyanobacterium Synechococcus PCC7942. The genes for three minimally related sHSPs, OsHSP from Oryza sativacytoplasm, tom111 from Lycopersicon esculentumchloroplasts, and 6803 HSP from Synechocystis sp. PCC6803, were cloned into the Escherichia coli vector pTrcHisA, so as to produce an N-terminal polyhistidine tag. The genes were transformed into E. coli and overexpressed. The tagged HSPs were purified (not completely in the case of tom111) by immobilised metal affinity chromatography. The native proteins exhibited a high degree of oligomerisation when analysed by size-exclusion chromatography. All three proteins were able to protect malate dehydrogenase (MDH) from in vitro thermal aggregation. They could also protect several soluble proteins in E. coli extracts from thermal aggregation in vitro, as well as protecting phycocyanin in extracts from Synechococcus sp. PCC7942. None of the proteins were able to protect photosystem II (measured as ΦPSII, the effective quantum fluorescence yield of PSII) of thylakoids isolated from Synechococcus sp. PCC7942 from heat damage in vitro, although in vivo, after acclimation, photosystem II did exhibit acquired thermotolerance.

scholarly journals Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro.

1989 ◽  
Vol 171 (3) ◽  
pp. 1590-1596 ◽  
Author(s):  
C Johnson ◽  
G N Chandrasekhar ◽  
C Georgopoulos
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock 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

Translation of Some Maize Small Heat Shock Proteins Is Initiated From Internal In-Frame AUGs

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 471-477
Author(s):  
J Roger H Frappier ◽  
David B Walden ◽  
Burr G Atkinson
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Single Gene ◽  
Small Heat Shock Proteins ◽  
Shock Proteins

Abstract Etiolated maize radicles (inbred Oh43) subjected to a brief heat shock synthesize a family of small heat shock proteins (≃18 kD) that is composed of at least 12 members. We previously described the cDNA-derived sequence of three maize shsp mRNAs (cMHSP18-1, cMHSP18-3, and cMHSP18-9). In this report, we demonstrate that the mRNA transcribed in vitro from one of these cDNAs (cMHSP 18-9) is responsible for the synthesis of three members of the shsp family, and we suggest that cMHSP18-3 may be responsible for the synthesis of three additional members and cMHSP18-1 for the synthesis of two other members of this family. The fact that these genes do not contain introns, coupled with the observations reported herein, suggest that maize may have established another method of using a single gene to produce a number of different 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.

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