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Biran D, Rotem O, Rosen R, Ron EZ. Coping with High Temperature: A Unique Regulation in A. tumefaciens. Curr Top Microbiol Immunol 2018; 418:185-194. [PMID: 30182196 DOI: 10.1007/82_2018_119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Elevation of temperature is a frequent and considerable stress for mesophilic bacteria. Therefore, several molecular mechanisms have evolved to cope with high temperature. We have been studying the response of Agrobacterium tumefaciens to temperature stress, focusing on two aspects: the heat-shock response and the temperature-dependent regulation of methionine biosynthesis. The results indicate that the molecular mechanisms involved in A. tumefaciens control of growth at high temperature are unique and we are still missing important information essential for understanding how these bacteria cope with temperature stress.
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Affiliation(s)
- Dvora Biran
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Or Rotem
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Ran Rosen
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Eliora Z Ron
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel.
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Njunge JM, Mandal P, Przyborski JM, Boshoff A, Pesce ER, Blatch GL. PFB0595w is a Plasmodium falciparum J protein that co-localizes with PfHsp70-1 and can stimulate its in vitro ATP hydrolysis activity. Int J Biochem Cell Biol 2015; 62:47-53. [PMID: 25701168 DOI: 10.1016/j.biocel.2015.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 12/01/2022]
Abstract
Heat shock proteins, many of which function as molecular chaperones, play important roles in the lifecycle and pathogenesis of the malaria parasite, Plasmodium falciparum. The P. falciparum heat shock protein 70 (PfHsp70) family of chaperones is potentially regulated by a large complement of J proteins that localize to various intracellular compartments including the infected erythrocyte cytosol. While PfHsp70-1 has been shown to be an abundant cytosolic chaperone, its regulation by J proteins is poorly understood. In this study, we characterized the J protein PFB0595w, a homologue of the well-studied yeast cytosolic J protein, Sis1. PFB0595w, similarly to PfHsp70-1, was localized to the parasite cytosol and its expression was upregulated by heat shock. Additionally, recombinant PFB0595w was shown to be dimeric and to stimulate the in vitro ATPase activity of PfHsp70-1. Overall, the expression, localization and biochemical data for PFB0595w suggest that it may function as a cochaperone of PfHsp70-1, and advances current knowledge on the chaperone machinery of the parasite.
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Affiliation(s)
- James M Njunge
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes, Rhodes University, Grahamstown 6140, South Africa
| | - Pradipta Mandal
- Parasitology, Philipps University Marburg, 35043 Marburg, Germany
| | | | - Aileen Boshoff
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes, Rhodes University, Grahamstown 6140, South Africa
| | - Eva-Rachele Pesce
- College of Health and Biomedicine, Victoria University, Melbourne 8001, VIC, Australia
| | - Gregory L Blatch
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes, Rhodes University, Grahamstown 6140, South Africa; College of Health and Biomedicine, Victoria University, Melbourne 8001, VIC, Australia.
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Cockburn IL, Pesce ER, Pryzborski JM, Davies-Coleman MT, Clark PG, Keyzers RA, Stephens LL, Blatch GL. Screening for small molecule modulators of Hsp70 chaperone activity using protein aggregation suppression assays: inhibition of the plasmodial chaperone PfHsp70-1. Biol Chem 2011; 392:431-8. [DOI: 10.1515/bc.2011.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Abstract
Plasmodium falciparum heat shock protein 70 (PfHsp70-1) is thought to play an essential role in parasite survival and virulence in the human host, making it a potential antimalarial drug target. A malate dehydrogenase based aggregation suppression assay was adapted for the screening of small molecule modulators of Hsp70. A number of small molecules of natural (marine prenylated alkaloids and terrestrial plant naphthoquinones) and related synthetic origin were screened for their effects on the protein aggregation suppression activity of purified recombinant PfHsp70-1. Five compounds (malonganenone A-C, lapachol and bromo-β-lapachona) were found to inhibit the chaperone activity of PfHsp70-1 in a concentration dependent manner, with lapachol preferentially inhibiting PfHsp70-1 compared to another control Hsp70. Using growth inhibition assays on P. falciparum infected erythrocytes, all of the compounds, except for malonganenone B, were found to inhibit parasite growth with IC50 values in the low micromolar range. Overall, this study has identified two novel classes of small molecule inhibitors of PfHsp70-1, one representing a new class of antiplasmodial compounds (malonganenones). In addition to demonstrating the validity of PfHsp70-1 as a possible drug target, the compounds reported in this study will be potentially useful as molecular probes for fundamental studies on Hsp70 chaperone function.
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Site-Saturation Mutagenesis of Leucine 134 of Bacillus licheniformis Nucleotide Exchange Factor GrpE Reveals the Importance of this Residue to the Co-chaperone Activity. Protein J 2010; 29:365-72. [DOI: 10.1007/s10930-010-9261-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Jewett AI, Shea JE. Reconciling theories of chaperonin accelerated folding with experimental evidence. Cell Mol Life Sci 2010; 67:255-76. [PMID: 19851829 PMCID: PMC11115962 DOI: 10.1007/s00018-009-0164-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 09/14/2009] [Accepted: 09/25/2009] [Indexed: 10/20/2022]
Abstract
For the last 20 years, a large volume of experimental and theoretical work has been undertaken to understand how chaperones like GroEL can assist protein folding in the cell. The most accepted explanation appears to be the simplest: GroEL, like most other chaperones, helps proteins fold by preventing aggregation. However, evidence suggests that, under some conditions, GroEL can play a more active role by accelerating protein folding. A large number of models have been proposed to explain how this could occur. Focused experiments have been designed and carried out using different protein substrates with conclusions that support many different mechanisms. In the current article, we attempt to see the forest through the trees. We review all suggested mechanisms for chaperonin-mediated folding and weigh the plausibility of each in light of what we now know about the most stringent, essential, GroEL-dependent protein substrates.
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Affiliation(s)
- Andrew I. Jewett
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
- Department of Physics, University of California, Santa Barbara, CA 93106 USA
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
- Department of Physics, University of California, Santa Barbara, CA 93106 USA
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Liang WC, Lin MG, Chou WM, Chi MC, Chang HP, Lin LL. Residues Leu52 and Leu134 are important for the structural integrity of a nucleotide exchange factor GrpE from Bacillus licheniformis. Int J Biol Macromol 2009; 45:352-8. [PMID: 19665474 DOI: 10.1016/j.ijbiomac.2009.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 07/30/2009] [Accepted: 07/30/2009] [Indexed: 11/30/2022]
Abstract
A DNA fragment encoding Bacillus licheniformis GrpE (BlGrpE) with double mutations at codons 52 and 134 was obtained during PCR cloning. Leu52 and Leu134 in BlGrpE were individually replaced with Pro and His to generate BlGrpE-L52P and BlGrpE-L134H. BlGrpE and BlGrpE-L52P synergistically stimulated the ATPase activity of B. licheniformis DnaK (BlDnaK); however, BlGrpE-L134H and the double-mutated protein (BlGrpE-L52P/L134H) had no co-chaperone function. BlGrpE, BlGrpE-L52P, and BlGrpE-L134H mainly interacted with the monomer of BlDnaK but non-specific interaction was observed for BlGrpE-L52P/L134H. Measurement of intrinsic fluorescence revealed a significant alteration of the microenvironment of aromatic acid residues in the mutant proteins. As compared with BlGrpE, quenching of 208-nm and 222-nm signals were observed in the mutant BlGrpEs and the single-mutated proteins were more sensitive to thermal denaturation.
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Affiliation(s)
- Wan-Chi Liang
- Department of Applied Chemistry, National Chiayi University, 300 University Road, Chiayi 600, Taiwan
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Louw CA, Ludewig MH, Blatch GL. Overproduction, purification and characterisation of Tbj1, a novel Type III Hsp40 from Trypanosoma brucei, the African sleeping sickness parasite. Protein Expr Purif 2009; 69:168-77. [PMID: 19815073 DOI: 10.1016/j.pep.2009.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/27/2009] [Accepted: 09/29/2009] [Indexed: 11/24/2022]
Abstract
The heat shock protein 40 (Hsp40) family of proteins act as co-chaperones of the heat shock protein 70 (Hsp70) chaperone family, and together they play a vital role in the maintenance of cellular homeostasis. The Type III class of Hsp40s are diverse in terms of both sequence identity and function and have not been extensively characterised. The Trypanosoma brucei parasite is the causative agent of Human African Trypanosomiasis, and possesses an unusually large Hsp40 complement, consisting mostly of Type III Hsp40s. A novel T. brucei Type III Hsp40, Tbj1, was heterologously expressed, purified, and found to exist as a compact monomer in solution. Using polyclonal antibodies to the full-length recombinant protein, Tbj1 was found by Western analysis to be expressed in the T. brucei bloodstream-form. Tbj1 was found to be able to assist two different Hsp70 proteins in the suppression of protein aggregation in vitro, despite being unable to stimulate their ATPase activity. This indicated that while Tbj1 did not possess independent chaperone activity, it potentially functioned as a novel co-chaperone of Hsp70 in T. brucei.
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Affiliation(s)
- Cassandra A Louw
- Biomedical Biotechnology Research Unit, Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, South Africa
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A 70-kDa molecular chaperone, DnaK, from the industrial bacterium Bacillus licheniformis: gene cloning, purification and molecular characterization of the recombinant protein. Indian J Microbiol 2009; 49:151-60. [PMID: 23100764 DOI: 10.1007/s12088-009-0029-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 11/27/2008] [Indexed: 12/24/2022] Open
Abstract
The heat shock protein 70 (Hsp70/DnaK) gene of Bacillus licheniformis is 1,839 bp in length encoding a polypeptide of 612 amino acid residues. The deduced amino acid sequence of the gene shares high sequence identity with other Hsp70/DnaK proteins. The characteristic domains typical for Hsps/DnaKs are also well conserved in B. licheniformis DnaK (BlDnaK). BlDnaK was overexpressed in Escherichia coli using pQE expression system and the recombinant protein was purified to homogeneity by nickel-chelate chromatography. The optimal temperature for ATPase activity of the purified BlDnaK was 40°C in the presence of 100 mM KCl. The purified BlDnaK had a V(max) of 32.5 nmol Pi/min and a K(M) of 439 μM. In vivo, the dnaK gene allowed an E. coli dnaK756-ts mutant to grow at 44°C, suggesting that BlDnaK should be functional for survival of host cells under environmental changes especially higher temperature. We also described the use of circular dichroism to characterize the conformation change induced by ATP binding. Binding of ATP was not accompanied by a net change in secondary structure, but ATP together with Mg(2+) and K(+) ions had a greater enhancement in the stability of BlDnaK at stress temperatures. Simultaneous addition of DnaJ, GrpE, and NR-peptide (NRLLLTG) synergistically stimulates the ATPase activity of BlDnaK by 11.7-fold.
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