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Lai MC, Cheng HY, Lew SH, Chen YA, Yu CH, Lin HY, Lin SM. Crystal structures of dimeric and heptameric mtHsp60 reveal the mechanism of chaperonin inactivation. Life Sci Alliance 2023; 6:e202201753. [PMID: 36973006 PMCID: PMC10053435 DOI: 10.26508/lsa.202201753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
Mitochondrial Hsp60 (mtHsp60) plays a crucial role in maintaining the proper folding of proteins in the mitochondria. mtHsp60 self-assembles into a ring-shaped heptamer, which can further form a double-ring tetradecamer in the presence of ATP and mtHsp10. However, mtHsp60 tends to dissociate in vitro, unlike its prokaryotic homologue, GroEL. The molecular structure of dissociated mtHsp60 and the mechanism behind its dissociation remain unclear. In this study, we demonstrated that Epinephelus coioides mtHsp60 (EcHsp60) can form a dimeric structure with inactive ATPase activity. The crystal structure of this dimer reveals symmetrical subunit interactions and a rearranged equatorial domain. The α4 helix of each subunit extends and interacts with its adjacent subunit, leading to the disruption of the ATP-binding pocket. Furthermore, an RLK motif in the apical domain contributes to stabilizing the dimeric complex. These structural and biochemical findings provide new insights into the conformational transitions and functional regulation of this ancient chaperonin.
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Affiliation(s)
- Meng-Cheng Lai
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Hao-Yu Cheng
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Sin-Hong Lew
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Yu-An Chen
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Chien-Hung Yu
- Department of Biochemistry and Molecular Biology, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Han-You Lin
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Shih-Ming Lin
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
- Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, Taiwan
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2
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Sokolova OS, Pichkur EB, Maslova ES, Kurochkina LP, Semenyuk PI, Konarev PV, Samygina VR, Stanishneva-Konovalova TB. Local Flexibility of a New Single-Ring Chaperonin Encoded by Bacteriophage AR9 Bacillus subtilis. Biomedicines 2022; 10:biomedicines10102347. [PMID: 36289609 PMCID: PMC9598537 DOI: 10.3390/biomedicines10102347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 11/25/2022] Open
Abstract
Chaperonins, a family of molecular chaperones, assist protein folding in all domains of life. They are classified into two groups: bacterial variants and those present in endosymbiotic organelles of eukaryotes belong to group I, while group II includes chaperonins from the cytosol of archaea and eukaryotes. Recently, chaperonins of a prospective new group were discovered in giant bacteriophages; however, structures have been determined for only two of them. Here, using cryo-EM, we resolved a structure of a new chaperonin encoded by gene 228 of phage AR9 B. subtilis. This structure has similarities and differences with members of both groups, as well as with other known phage chaperonins, which further proves their diversity.
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Affiliation(s)
- Olga S. Sokolova
- Faculty of Biology, MSU-BIT Shenzhen University, Shenzhen 518172, China
| | - Evgeny B. Pichkur
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123098 Moscow, Russia
| | | | - Lidia P. Kurochkina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Pavel I. Semenyuk
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Petr V. Konarev
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123098 Moscow, Russia
- Shubnikov Institute of Crystallography of FSRC “Crystallography and Photonics”, RAS, 119333 Moscow, Russia
| | - Valeriya R. Samygina
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123098 Moscow, Russia
- Shubnikov Institute of Crystallography of FSRC “Crystallography and Photonics”, RAS, 119333 Moscow, Russia
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3
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Vilasi S, Carrotta R, Ricci C, Rappa GC, Librizzi F, Martorana V, Ortore MG, Mangione MR. Inhibition of Aβ 1-42 Fibrillation by Chaperonins: Human Hsp60 Is a Stronger Inhibitor than Its Bacterial Homologue GroEL. ACS Chem Neurosci 2019; 10:3565-3574. [PMID: 31298838 DOI: 10.1021/acschemneuro.9b00183] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease is a chronic neurodegenerative disease characterized by the accumulation of pathological aggregates of amyloid beta peptide. Many efforts have been focused on understanding peptide aggregation pathways and on identification of molecules able to inhibit aggregation in order to find an effective therapy. As a result, interest in neuroprotective proteins, such as molecular chaperones, has increased as their normal function is to assist in protein folding or to facilitate the disaggregation and/or clearance of abnormal aggregate proteins. Using biophysical techniques, we evaluated the effects of two chaperones, human Hsp60 and bacterial GroEL, on the fibrillogenesis of Aβ1-42. Both chaperonins interfere with Aβ1-42 aggregation, but the effect of Hsp60 is more significant and correlates with its more pronounced flexibility and stronger interaction with ANS, an indicator of hydrophobic regions. Dose-dependent ThT fluorescence kinetics and SAXS experiments reveal that Hsp60 does not change the nature of the molecular processes stochastically leading to the formation of seeds, but strongly delays them by recognition of hydrophobic sites of some peptide species crucial for triggering amyloid formation. Hsp60 reduces the initial chaotic heterogeneity of Aβ1-42 sample at high concentration regimes. The understanding of chaperone action in counteracting pathological aggregation could be a starting point for potential new therapeutic strategies against neurodegenerative diseases.
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Affiliation(s)
- Silvia Vilasi
- Institute of Biophysics, National Research Council, Palermo 90146, Italy
| | - Rita Carrotta
- Institute of Biophysics, National Research Council, Palermo 90146, Italy
| | - Caterina Ricci
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy
| | | | - Fabio Librizzi
- Institute of Biophysics, National Research Council, Palermo 90146, Italy
| | - Vincenzo Martorana
- Institute of Biophysics, National Research Council, Palermo 90146, Italy
| | - Maria Grazia Ortore
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona 60131, Italy
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4
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Marino Gammazza A, Macaluso F, Di Felice V, Cappello F, Barone R. Hsp60 in Skeletal Muscle Fiber Biogenesis and Homeostasis: From Physical Exercise to Skeletal Muscle Pathology. Cells 2018; 7:cells7120224. [PMID: 30469470 PMCID: PMC6315887 DOI: 10.3390/cells7120224] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/13/2022] Open
Abstract
Hsp60 is a molecular chaperone classically described as a mitochondrial protein with multiple roles in health and disease, participating to the maintenance of protein homeostasis. It is well known that skeletal muscle is a complex tissue, rich in proteins, that is, subjected to continuous rearrangements, and this homeostasis is affected by many different types of stimuli and stresses. The regular exercise induces specific histological and biochemical adaptations in skeletal muscle fibers, such as hypertrophy and an increase of mitochondria activity and oxidative capacity. The current literature is lacking in information regarding Hsp60 involvement in skeletal muscle fiber biogenesis and regeneration during exercise, and in disease conditions. Here, we briefly discuss the functions of Hsp60 in skeletal muscle fibers during exercise, inflammation, and ageing. Moreover, the potential usage of Hsp60 as a marker for disease and the evaluation of novel treatment options is also discussed. However, some questions remain open, and further studies are needed to better understand Hsp60 involvement in skeletal muscle homeostasis during exercise and in pathological condition.
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Affiliation(s)
- Antonella Marino Gammazza
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90100 Palermo, Italy.
| | - Filippo Macaluso
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90100 Palermo, Italy.
- Department of SMART Engineering Solutions & Technologies, eCampus University, 22060 Novedrate, Italy.
| | - Valentina Di Felice
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, 90127 Palermo, Italy.
| | - Francesco Cappello
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90100 Palermo, Italy.
| | - Rosario Barone
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90100 Palermo, Italy.
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5
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Piana S, Shaw DE. Atomic-Level Description of Protein Folding inside the GroEL Cavity. J Phys Chem B 2018; 122:11440-11449. [PMID: 30277396 DOI: 10.1021/acs.jpcb.8b07366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chaperonins (ubiquitous facilitators of protein folding) sequester misfolded proteins within an internal cavity, thus preventing protein aggregation during the process of refolding. GroEL, a tetradecameric bacterial chaperonin, is one of the most studied chaperonins, but the role of the internal cavity in the refolding process is still unclear. It has been suggested that rather than simply isolating proteins while they refold, the GroEL cavity actively promotes protein folding. A detailed characterization of the folding dynamics and thermodynamics of protein substrates encapsulated within the cavity, however, has been difficult to obtain by experimental means, due to the system's complexity and the many steps in the folding cycle. Here, we examine the influence of the GroEL cavity on protein folding based on the results of unbiased, atomistic molecular dynamics simulations. We first verified that the computational setup, which uses a recently developed state-of-the-art force field that more accurately reproduces the aggregation propensity of unfolded states, could recapitulate the essential structural dynamics of GroEL. In these simulations, the GroEL tetradecamer was highly dynamic, transitioning among states corresponding to most of the structures that have been observed experimentally. We then simulated a small, unfolded protein both in the GroEL cavity and in bulk solution and compared the protein's folding process within these two environments. Inside the GroEL cavity, the unfolded protein interacted strongly with the disordered residues in GroEL's C-terminal tails. These interactions stabilized the protein's unfolded states relative to its compact states and increased the roughness of its folding free-energy surface, resulting in slower folding compared to the rate in solution. For larger proteins, which are more typical GroEL substrates, we speculate that these interactions may allow substrates to more quickly escape kinetic traps associated with compact, misfolded states, thereby actively promoting folding.
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Affiliation(s)
- Stefano Piana
- D. E. Shaw Research , New York , New York 10036 , United States
| | - David E Shaw
- D. E. Shaw Research , New York , New York 10036 , United States.,Department of Biochemistry and Molecular Biophysics , Columbia University , New York , New York 10032 , United States
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6
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Heat Shock Proteins in Alzheimer's Disease: Role and Targeting. Int J Mol Sci 2018; 19:ijms19092603. [PMID: 30200516 PMCID: PMC6163571 DOI: 10.3390/ijms19092603] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022] Open
Abstract
Among diseases whose cure is still far from being discovered, Alzheimer’s disease (AD) has been recognized as a crucial medical and social problem. A major issue in AD research is represented by the complexity of involved biochemical pathways, including the nature of protein misfolding, which results in the production of toxic species. Considering the involvement of (mis)folding processes in AD aetiology, targeting molecular chaperones represents a promising therapeutic perspective. This review analyses the connection between AD and molecular chaperones, with particular attention toward the most important heat shock proteins (HSPs) as representative components of the human chaperome: Hsp60, Hsp70 and Hsp90. The role of these proteins in AD is highlighted from a biological point of view. Pharmacological targeting of such HSPs with inhibitors or regulators is also discussed.
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Vilasi S, Bulone D, Caruso Bavisotto C, Campanella C, Marino Gammazza A, San Biagio PL, Cappello F, Conway de Macario E, Macario AJL. Chaperonin of Group I: Oligomeric Spectrum and Biochemical and Biological Implications. Front Mol Biosci 2018; 4:99. [PMID: 29423396 PMCID: PMC5788889 DOI: 10.3389/fmolb.2017.00099] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 12/28/2017] [Indexed: 01/13/2023] Open
Abstract
Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM), is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still incompletely understood. Chaperonin I in eukaryotes occurs in various locations, not just the mitochondrion, which is its canonical place of residence and function. Eukaryotic Chaperonin I, namely Hsp60 (designated HSP60 or HSPD1 in humans) has, indeed, been found in the cytosol; the plasma-cell membrane; on the outer surface of cells; in the intercellular space; in biological liquids such as lymph, blood, and cerebrospinal fluid; and in secretions, for instance saliva and urine. Hsp60 has also been found in cell-derived vesicles such as exosomes. The functions of Hsp60 in all these non-canonical locales are still poorly characterized and one of the questions not yet answered is in what form, i.e., monomer or oligomer, is the chaperonin present in these non-canonical locations. In view of the steady increase in interest on chaperonopathies over the last several years, we have studied human HSP60 to determine its role in various diseases, its locations in cells and tissues and migrations in the body, and its post-translational modifications that might have an impact on its location and function. We also carried out experiments to characterize the oligomeric status of extramitochondrial of HSP60 in solution. Here, we provide an overview of our results, focusing on the oligomeric equilibrium and stability of the various forms of HSP60 in comparison with GroEL. We also discuss post-translational modifications associated with anti-cancer drugs to indicate the potential of Hsp60 in Medicine, as a biomarker and etiopathogenic factor.
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Affiliation(s)
- Silvia Vilasi
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Donatella Bulone
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Celeste Caruso Bavisotto
- Section of Human Anatomy, Department of Experimental Biomedicine and Clinical Neuroscience (BIONEC), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy
| | - Claudia Campanella
- Section of Human Anatomy, Department of Experimental Biomedicine and Clinical Neuroscience (BIONEC), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy
| | - Antonella Marino Gammazza
- Section of Human Anatomy, Department of Experimental Biomedicine and Clinical Neuroscience (BIONEC), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy
| | | | - Francesco Cappello
- Section of Human Anatomy, Department of Experimental Biomedicine and Clinical Neuroscience (BIONEC), University of Palermo, Palermo, Italy.,Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy
| | - Everly Conway de Macario
- Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology (IMET), Columbus Center, Baltimore, MD, United States
| | - Alberto J L Macario
- Euro-Mediterranean Institute of Science and Technology (IEMEST), Palermo, Italy.,Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology (IMET), Columbus Center, Baltimore, MD, United States
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8
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Ricci C, Carrotta R, Rappa GC, Mangione MR, Librizzi F, San Biagio PL, Amenitsch H, Ortore MG, Vilasi S. Investigation on different chemical stability of mitochondrial Hsp60 and its precursor. Biophys Chem 2017; 229:31-38. [DOI: 10.1016/j.bpc.2017.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/13/2017] [Accepted: 07/21/2017] [Indexed: 11/26/2022]
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9
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Chen J, Zhang Q, Ren W, Li W. Piecing Together the Allosteric Patterns of Chaperonin GroEL. J Phys Chem B 2017; 121:4987-4996. [PMID: 28430446 DOI: 10.1021/acs.jpcb.7b01992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite considerable efforts, elucidating the allostery of large macromolecular assemblies at a molecular level in solution remains technically challenging due to its structural complexity. Here we have employed an approach combining amide backbone hydrogen/deuterium exchange coupled with mass spectrometry, fluorescence spectroscopy, and molecular simulations to characterize allosteric patterns of chaperonin GroEL, an ∼800 kDa tetradecamer from E. coli. Using available crystal structures of GroEL, we quantitatively map out GroEL allosteric changes in solution by resolving exchange behaviors of 133 overlapping proteolytic peptides with more than 95% sequence coverage. This comprehensive analysis gives a refined resolution down to five residues to pilot the GroEL allosteric determinants, of which the localized dynamics is monitored by tryptophan-mutated GroEL. Furthermore, the GroEL conformational transition is evaluated by molecular dynamics simulations with an atomic-interaction-based coarse-grained model. Collectively, we provide a practical methodology to analyze GroEL allostery in solution.
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Affiliation(s)
- Jin Chen
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences , Okazaki 444-8787, Japan
| | - Qian Zhang
- Department of Chemistry, Florida State University , Tallahassee, Florida 32306, United States
| | - Weitong Ren
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Wenfei Li
- National Laboratory of Solid State Microstructure, Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
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10
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The inhibition of glycerol permeation through aquaglyceroporin-3 induced by mercury(II): A molecular dynamics study. J Inorg Biochem 2016; 160:78-84. [DOI: 10.1016/j.jinorgbio.2015.11.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/05/2015] [Accepted: 11/30/2015] [Indexed: 11/22/2022]
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11
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Spinello A, Barone G, Cappello F, Pace A, Buscemi S, Palumbo Piccionello A. The Binding Mechanism of Epolactaene to Hsp60 Unveiled by in Silico Modelling. ChemistrySelect 2016. [DOI: 10.1002/slct.201600125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Angelo Spinello
- Dipartimento di Scienze e Tecnologie Biologiche; Chimiche e Farmaceutiche-STEBICEF; University of Palermo; V.le delle Scienze Ed.17 90128 Palermo Italy
- Istituto Euro-Mediterraneo di Scienza e Tecnologia-IEMEST; Via Michele Miraglia 20 90139 Palermo Italy
| | - Giampaolo Barone
- Dipartimento di Scienze e Tecnologie Biologiche; Chimiche e Farmaceutiche-STEBICEF; University of Palermo; V.le delle Scienze Ed.17 90128 Palermo Italy
- Istituto Euro-Mediterraneo di Scienza e Tecnologia-IEMEST; Via Michele Miraglia 20 90139 Palermo Italy
| | - Francesco Cappello
- Istituto Euro-Mediterraneo di Scienza e Tecnologia-IEMEST; Via Michele Miraglia 20 90139 Palermo Italy
- Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche -BIONEC; University of Palermo; Via del Vespro 129 90127 Palermo Italy
| | - Andrea Pace
- Dipartimento di Scienze e Tecnologie Biologiche; Chimiche e Farmaceutiche-STEBICEF; University of Palermo; V.le delle Scienze Ed.17 90128 Palermo Italy
- Istituto Euro-Mediterraneo di Scienza e Tecnologia-IEMEST; Via Michele Miraglia 20 90139 Palermo Italy
| | - Silvestre Buscemi
- Dipartimento di Scienze e Tecnologie Biologiche; Chimiche e Farmaceutiche-STEBICEF; University of Palermo; V.le delle Scienze Ed.17 90128 Palermo Italy
| | - Antonio Palumbo Piccionello
- Dipartimento di Scienze e Tecnologie Biologiche; Chimiche e Farmaceutiche-STEBICEF; University of Palermo; V.le delle Scienze Ed.17 90128 Palermo Italy
- Istituto Euro-Mediterraneo di Scienza e Tecnologia-IEMEST; Via Michele Miraglia 20 90139 Palermo Italy
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Stability and disassembly properties of human naïve Hsp60 and bacterial GroEL chaperonins. Biophys Chem 2015; 208:68-75. [PMID: 26259786 DOI: 10.1016/j.bpc.2015.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 07/17/2015] [Accepted: 07/19/2015] [Indexed: 02/03/2023]
Abstract
Human Hsp60 chaperonin and its bacterial homolog GroEL, in association with the corresponding co-chaperonins Hsp10 and GroES, constitute important chaperone systems promoting the proper folding of several mitochondrial proteins. Hsp60 is also currently described as a ubiquitous molecule with multiple roles both in health conditions and in several diseases. Naïve Hsp60 bearing the mitochondrial import signal has been recently demonstrated to present different oligomeric organizations with respect to GroEL, suggesting new possible physiological functions. Here we present a combined investigation with circular dichroism and small-angle X-ray scattering of structure, self-organization, and stability of naïve Hsp60 in solution in comparison with bacterial GroEL. Experiments have been performed in different concentrations of guanidine hydrochloride, monitoring the dissociation of tetradecamers into heptamers and monomers, until unfolding. GroEL is proved to be more stable with respect to Hsp60, and the unfolding free energy as well as its dependence on denaturant concentration is obtained.
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