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McFarland R, Reichow S. Dynamic fibrillar assembly of αB-crystallin induced by perturbation of the conserved NT-IXI motif resolved by cryo-EM. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586355. [PMID: 38585788 PMCID: PMC10996541 DOI: 10.1101/2024.03.22.586355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
αB-crystallin is an archetypical member of the small heat-shock proteins (sHSPs) vital for cellular proteostasis and mitigating protein misfolding diseases. Gaining insights into the principles defining their molecular organization and chaperone function have been hindered by intrinsic dynamic properties and limited high-resolution structural analysis. To disentangle the mechanistic underpinnings of these dynamical properties, we mutated a conserved IXI-motif located within the N-terminal (NT) domain of human αB-crystallin. This resulted in a profound structural transformation, from highly polydispersed caged-like native assemblies into a comparatively well-ordered helical fibril state amenable to high-resolution cryo-EM analysis. The reversible nature of the induced fibrils facilitated interrogation of functional effects due to perturbation of the NT-IXI motif in both the native-like oligomer and fibril states. Together, our investigations unveiled several features thought to be key mechanistic attributes to sHSPs and point to a critical significance of the NT-IXI motif in αB-crystallin assembly, dynamics and chaperone activity.
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Affiliation(s)
- Russell McFarland
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
- Current: Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Steve Reichow
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
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2
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Kurre D, Suguna K. Network of Entamoeba histolytica HSP18.5 dimers formed by two overlapping [IV]-X-[IV] motifs. Proteins 2021; 89:1039-1054. [PMID: 33792100 DOI: 10.1002/prot.26081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 02/19/2021] [Accepted: 03/22/2021] [Indexed: 11/11/2022]
Abstract
Small heat shock proteins (sHSPs) are ATP-independent molecular chaperones with low molecular weight that prevent the aggregation of proteins during stress conditions and maintain protein homeostasis in the cell. sHSPs exist in dynamic equilibrium as a mixture of oligomers of various sizes with a constant exchange of subunits between them. Many sHSPs form cage-like assemblies that may dissociate into smaller oligomers during stress conditions. We carried out the functional and structural characterization of a small heat shock protein, HSP18.5, from Entamoeba histolytica (EhHSP18.5). It showed a pH-dependent change in its oligomeric state, which varied from a tetramer to larger than 48-mer. EhHSP18.5 protected Nde I and lysozyme substrates from temperature and chemical stresses, respectively. The crystal structure of EhHSP18.5 was determined at a resolution of 3.28 Å in C2221 cell with four subunits in the asymmetric unit forming two non-metazoan sHSP-type dimers. Unlike the reported cage-like structures, EhHSP18.5 formed a network of linear chains of molecules in the crystal. Instead of a single [IV]-X-[IV] motif, EhHSP18.5 has two overlapping I/V-X-I/V sequences at the C-terminus giving rise to novel interactions between the dimers. Negative staining Electron Microscopy images of EhHSP18.5 showed the presence of multiple oligomers: closed structures of various sizes and long tube-like structures.
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Affiliation(s)
- Devanshu Kurre
- Molecular Biophysics unit, Indian Institute of Science, Bangalore, India
| | - Kaza Suguna
- Molecular Biophysics unit, Indian Institute of Science, Bangalore, India
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Liu D, Chen Q, Zhang L, Hu H, Yin C. AgsA oligomer acts as a functional unit. Biochem Biophys Res Commun 2020; 530:22-28. [PMID: 32828289 DOI: 10.1016/j.bbrc.2020.07.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 11/18/2022]
Abstract
AgsA (aggregation-suppressing protein) is an ATP-independent molecular chaperone machine belonging to the family of small heat shock proteins (sHSP), and it can prevent the aggregation of non-natural proteins. However, the substrate-binding site of AgsA and the functional unit that captures and binds the substrate remain unknown. In this study, different N-terminal and C-terminal deletion mutants of AgsA were constructed and their effects on AgsA oligomer assembly and chaperone activity were investigated. We found that the IXI motif at the C-terminus and the α-helix at the N-terminus affected the oligomerization and molecular chaperone activity of AgsA. In this work, we obtained a 6.8 Å resolution structure of AgsA using Electron cryo-microscopy (cryo-EM), and found that the functional form of AgsA was an 18-mer with D3 symmetry. Through amino acid mutations, disulfide bonds were introduced into two oligomeric interfaces, namely dimeric interface and non-partner interface. Under oxidation and reduction conditions, the chaperone activity of the disulfide-bonded AgsA did not change significantly, indicating that AgsA would not dissociate to achieve chaperone activity. Therefore, we concluded that the oligomer, especially 18-mer, was the primary functional unit.
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Affiliation(s)
- Dongmei Liu
- Department of Biochemistry and Biophysics, The Health Science Center, Peking University, Beijing, 100191, China.
| | - Qiang Chen
- The Chinese University of Hong Kong, Shenzhen, Shenzhen, Guangdong, 518172, PR China.
| | - Lei Zhang
- Department of Biochemistry and Biophysics, The Health Science Center, Peking University, Beijing, 100191, China; Electron Microscopy Analysis Laboratory, Center of Medical and Health Analysis, Peking University, Beijing, 100191, China.
| | - Hongli Hu
- The Chinese University of Hong Kong, Shenzhen, Shenzhen, Guangdong, 518172, PR China.
| | - Changcheng Yin
- Department of Biochemistry and Biophysics, The Health Science Center, Peking University, Beijing, 100191, China; Electron Microscopy Analysis Laboratory, Center of Medical and Health Analysis, Peking University, Beijing, 100191, China.
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Lv Y, Ezemaduka AN, Wang Y, Xu J, Li X. AgsA response to cadmium and copper effects at different temperatures in Escherichia coli. J Biochem Mol Toxicol 2019; 33:e22344. [PMID: 31211484 DOI: 10.1002/jbt.22344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/31/2019] [Accepted: 04/04/2019] [Indexed: 11/06/2022]
Abstract
Small heat shock proteins (sHsps), present from prokaryotes to eukaryotes, are a highly conserved molecular chaperone family. They play a crucial role in protecting organisms against cellular insults from single or multiple environmental stressors including heavy metal exposure, heat or cold shock, oxidative stress, desiccation, etc. Here, the toxicity of cadmium and copper, and their ability to modify the cellular growth rate at different temperatures in Escherichia coli cells were tested. Also, the response mechanism of the sHSP aggregation-suppressing protein (AgsA) in such multiple stress conditions was investigated. The results showed that the half effect concentration (EC50 ) of cadmium in AgsA-transformed E. coli cells at 37°C, 42°C, and 50°C were 11.106, 29.50, and 4.35 mg/L, respectively, and that of the control cells lacking AgsA were 5.05, 0.93, and 0.18 mg/L, respectively, while the half effect concentration (EC50 ) of copper in AgsA-transformed E. coli cells at 37°C, 42°C, and 50°C were 27.3, 3.40, and 1.28 mg/L, respectively, and that of the control cells lacking AgsA were 27.7, 5.93, and 0.134 mg/L, respectively. The toxicities of cadmium and copper at different temperatures as observed by their modification of the cellular growth rate and inhibitory effects were in a dose-dependent manner. Additionally, biochemical characterization of AgsA protein in cells subjected to cadmium and copper stresses at different temperatures implicated suppressed aggregation of cellular proteins in AgsA-transformed E. coli cells. Altogether, our data implicate the AgsA protein as a sensitive protein-based biomarker for metal-induced toxicity monitoring.
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Affiliation(s)
- Yanchun Lv
- Environmental Sciences, School of Environment, Northeast Normal University, Changchun, China
| | - Anastasia N Ezemaduka
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Yunbiao Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Jingbo Xu
- Environmental Sciences, School of Environment, Northeast Normal University, Changchun, China
| | - Xiujun Li
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
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Ezemaduka AN, Lv Y, Wang Y, Xu J, Li X. Heterologous expression of AgsA enhances Escherichia coli tolerance to the combined effect of elevated temperature and Zinc toxicity. J Therm Biol 2018; 72:137-142. [PMID: 29496006 DOI: 10.1016/j.jtherbio.2018.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 01/21/2023]
Abstract
Small heat shock proteins (sHSPs) are ubiquitous stress proteins that are able to protect the cells against cellular insults from temperature, heavy metal etc. However, the molecular chaperone roles of sHSPs in enhancing growth and adaptation under combined temperature and metal stresses in Escherichia coli cells have been poorly understood. Here, we analyze the function of recombinant AgsA, a small heat shock protein from Salmonella enterica serovar Typhimurium under combined temperature and zinc stress in E. coli. Our results show that the heterologous expression of AgsA significantly increases the tolerance of E. coli cells to the combined effect of temperature stress and zinc toxicity by maintaining the stability of soluble proteins. Furthermore, there was remarkable and significant difference in the half effect concentration (EC50) of zinc at all temperatures treatments in both test cells. The EC50s of zinc at 37 °C, 42 °C and 50 °C were 15.24 mg/L, 29.30 mg/L, and 5.98 mg/L respectively in the AgsA-transformed E. coli cells, and 3.03 mg/L, 2.38 mg/L, and 0.373 mg/L, respectively in the control cells lacking AgsA. Together, our data indicate a good concentration-response relationship between all three temperatures treatment and zinc toxicity in E. coli, and establish for the first time the combined effects of temperature and zinc toxicity on E. coli cells. Also, the AgsA protein response to combined thermal and metal stress could serve as a molecular biomarker for the assessment of interactive stress damage to the cells.
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Affiliation(s)
- Anastasia N Ezemaduka
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, China
| | - Yanchun Lv
- School of Environment, Northeast Normal University, Changchun 130024, China
| | - Yunbiao Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, China
| | - Jingbo Xu
- School of Environment, Northeast Normal University, Changchun 130024, China.
| | - Xiujun Li
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, China.
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Mani N, Bhandari S, Moreno R, Hu L, Prasad BVV, Suguna K. Multiple oligomeric structures of a bacterial small heat shock protein. Sci Rep 2016; 6:24019. [PMID: 27053150 PMCID: PMC4823740 DOI: 10.1038/srep24019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 03/14/2016] [Indexed: 11/23/2022] Open
Abstract
Small heat shock proteins are ubiquitous molecular chaperones that form the first line of defence against the detrimental effects of cellular stress. Under conditions of stress they undergo drastic conformational rearrangements in order to bind to misfolded substrate proteins and prevent cellular protein aggregation. Owing to the dynamic nature of small heat shock protein oligomers, elucidating the structural basis of chaperone action and oligomerization still remains a challenge. In order to understand the organization of sHSP oligomers, we have determined crystal structures of a small heat shock protein from Salmonella typhimurium in a dimeric form and two higher oligomeric forms: an 18-mer and a 24-mer. Though the core dimer structure is conserved in all the forms, structural heterogeneity arises due to variation in the terminal regions.
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Affiliation(s)
- Nandini Mani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Spraha Bhandari
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rodolfo Moreno
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - B V Venkataram Prasad
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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A novel mechanism for small heat shock proteins to function as molecular chaperones. Sci Rep 2015; 5:8811. [PMID: 25744691 PMCID: PMC4351549 DOI: 10.1038/srep08811] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 02/04/2015] [Indexed: 11/08/2022] Open
Abstract
Small heat shock proteins (sHSPs) are molecular chaperones ubiquitously present in all forms of life, but their function mechanisms remain controversial. Here we show by cryo-electron microscopy and single particle 3D reconstruction that, at the low temperatures (4-25°C), CeHSP17 (a sHSP from Caenorhabditis elegans) exists as a 24-subunit spherical oligomer with tetrahedral symmetry. Our studies demonstrate that CeHSP17 forms large sheet-like super-molecular assemblies (SMAs) at the high temperatures (45-60°C), and such SMAs are apparently the form that exhibits chaperone-like activity. Our findings suggest a novel molecular mechanism for sHSPs to function as molecular chaperones.
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Oligomer-dependent and -independent chaperone activity of sHsps in different stressed conditions. FEBS Open Bio 2015; 5:155-62. [PMID: 25834780 PMCID: PMC4359974 DOI: 10.1016/j.fob.2015.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/20/2015] [Accepted: 02/28/2015] [Indexed: 12/12/2022] Open
Abstract
A great number of studies have proven that sHsps protect cells by inhibiting protein aggregation under heat stress, while little is known about their function to protect cells under acid stress. In this work, we show that Hsp20.1 and Hsp14.1 oligomers dissociated to smaller oligomeric species or even dimer/monomer at low pH (pH 4.0 and pH 2.0), whereas no prominent quaternary structural changes were seen at 50 °C. Both oligomers and smaller oligomeric species exhibited abilities to suppress client aggregation at low pH and at 50 °C. These results suggest that sHsps may function in different modes in different stressed conditions.
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Chang Z. Understanding What Small Heat Shock Proteins Do for Bacterial Cells. HEAT SHOCK PROTEINS 2015. [DOI: 10.1007/978-3-319-16077-1_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
Small heat-shock proteins (sHSPs) are ubiquitous ATP-independent molecular chaperones that play crucial roles in protein quality control in cells. They are able to prevent the aggregation and/or inactivation of various non-native substrate proteins and assist the refolding of these substrates independently or under the help of other ATP-dependent chaperones. Substrate recognition and binding by sHSPs are essential for their chaperone functions. This review focuses on what natural substrate proteins an sHSP protects and how it binds the substrates in cells under fluctuating conditions. It appears that sHSPs of prokaryotes, although being able to bind a wide range of cellular proteins, preferentially protect certain classes of functional proteins, such as translation-related proteins and metabolic enzymes, which may well explain why they could increase the resistance of host cells against various stresses. Mechanistically, the sHSPs of prokaryotes appear to possess numerous multi-type substrate-binding residues and are able to hierarchically activate these residues in a temperature-dependent manner, and thus act as temperature-regulated chaperones. The mechanism of hierarchical activation of substrate-binding residues is also discussed regarding its implication for eukaryotic sHSPs.
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Affiliation(s)
- Xinmiao Fu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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11
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A small heat shock protein enables Escherichia coli to grow at a lethal temperature of 50°C conceivably by maintaining cell envelope integrity. J Bacteriol 2014; 196:2004-11. [PMID: 24659772 DOI: 10.1128/jb.01473-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is essential for organisms to adapt to fluctuating growth temperatures. Escherichia coli, a model bacterium commonly used in research and industry, has been reported to grow at a temperature lower than 46.5°C. Here we report that the heterologous expression of the 17-kDa small heat shock protein from the nematode Caenorhabditis elegans, CeHSP17, enables E. coli cells to grow at 50°C, which is their highest growth temperature ever reported. Strikingly, CeHSP17 also rescues the thermal lethality of an E. coli mutant deficient in degP, which encodes a protein quality control factor localized in the periplasmic space. Mechanistically, we show that CeHSP17 is partially localized in the periplasmic space and associated with the inner membrane of E. coli, and it helps to maintain the cell envelope integrity of the E. coli cells at the lethal temperatures. Together, our data indicate that maintaining the cell envelope integrity is crucial for the E. coli cells to grow at high temperatures and also shed new light on the development of thermophilic bacteria for industrial application.
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Chen J, Yagi H, Sormanni P, Vendruscolo M, Makabe K, Nakamura T, Goto Y, Kuwajima K. Fibrillogenic propensity of the GroEL apical domain: a Janus-faced minichaperone. FEBS Lett 2012; 586:1120-7. [PMID: 22575645 DOI: 10.1016/j.febslet.2012.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/21/2012] [Accepted: 03/09/2012] [Indexed: 11/19/2022]
Abstract
The chaperonin GroEL plays an essential role in promoting protein folding and in protecting against misfolding and aggregation in the cellular environment. In this study, we report that both GroEL and its isolated apical domain form amyloid-like fibrils under physiological conditions, and that the fibrillation of the apical domain is accelerated under acidic conditions. We also found, however, that despite its fibrillation propensity, the apical domain exhibits a pronounced inhibitory effect on the fibril growth of β(2)-microglobulin. Thus, the analysis of the behaviour of the apical domain reveals how aggregation and chaperone-mediated anti-aggregation processes can be closely related.
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Affiliation(s)
- Jin Chen
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Japan.
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