1
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Thapliyal C, Mishra R. The Chaperone-Active State of HdeB at pH 4 Arises from Its Conformational Rearrangement and Enhanced Stability Instead of Surface Hydrophobicity. Biochemistry 2024; 63:1147-1161. [PMID: 38640496 DOI: 10.1021/acs.biochem.4c00132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
HdeA and HdeB are dimeric ATP-independent acid-stress chaperones, which protect the periplasmic proteins of enteric bacteria at pH 2.0 and 4.0, respectively, during their passage through the acidic environment of the mammalian stomach. Despite being structurally similar, they exhibit distinct functional pH optima and conformational prerequisite for their chaperone action. HdeA undergoes a dimer-to-monomer transition at pH 2.0, whereas HdeB remains dimeric at pH 4.0. The monomerization of HdeA exposes its hydrophobic motifs, which facilitates its interaction with the partially folded substrates. How HdeB functions despite maintaining its dimeric conformation has been poorly elucidated in the literature. Herein, we characterized the conformational states and stability of HdeB at its physiologically relevant pH and compared the data with those of HdeA. At pH 4.0, HdeB exhibited distinct spectroscopic signatures and higher stability against heat and guanidine-HCl-induced denaturation than at pH 7.5. We affirm that the pH 4.0 conformer of HdeB was distinct from that at pH 7.5 and that these two conformational states were hierarchically unrelated. Salt-bridge mutations that perturbed HdeB's intersubunit interactions resulted in the loss of its stability and function at pH 4.0. In contrast, mutations affecting intrasubunit interactions enhanced its function, albeit with a reduction in stability. These findings suggest that, unlike HdeA, HdeB acts as a noncanonical chaperone, where pH-dependent stability and conformational rearrangement at pH 4.0 play a core role in its chaperone function rather than its surface hydrophobicity. Such rearrangement establishes a stability-function trade-off that allows HdeB to function while maintaining its stable dimeric state.
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Affiliation(s)
- Charu Thapliyal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rajesh Mishra
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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2
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Nakata Y, Kitazaki Y, Kanaoka H, Shingen E, Uehara R, Hongo K, Kawata Y, Mizobata T. Formation of Fibrils by the Periplasmic Molecular Chaperone HdeB from Escherichia coli. Int J Mol Sci 2022; 23:ijms232113243. [PMID: 36362039 PMCID: PMC9657021 DOI: 10.3390/ijms232113243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/19/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
The molecular chaperones HdeA and HdeB of the Escherichia coli (E. coli) periplasm protect client proteins from acid denaturation through a unique mechanism that utilizes their acid denatured states to bind clients. We previously demonstrated that the active, acid-denatured form of HdeA is also prone to forming inactive, amyloid fibril-like aggregates in a pH-dependent, reversible manner. In this study, we report that HdeB also displays a similar tendency to form fibrils at low pH. HdeB fibrils were observed at pH < 3 in the presence of NaCl. Similar to HdeA, HdeB fibrils could be resolubilized by a simple shift to neutral pH. In the case of HdeB, however, we found that after extended incubation at low pH, HdeB fibrils were converted into a form that could not resolubilize at pH 7. Fresh fibrils seeded from these “transformed” fibrils were also incapable of resolubilizing at pH 7, suggesting that the transition from reversible to irreversible fibrils involved a specific conformational change that was transmissible through fibril seeds. Analyses of fibril secondary structure indicated that HdeB fibrils retained significant alpha helical content regardless of the conditions under which fibrils were formed. Fibrils that were formed from HdeB that had been treated to remove its intrinsic disulfide bond also were incapable of resolubilizing at pH 7, suggesting that certain residual structures that are retained in acid-denatured HdeB are important for this protein to recover its soluble state from the fibril form.
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Affiliation(s)
- Yui Nakata
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
| | - Yuuto Kitazaki
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
| | - Hitomi Kanaoka
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
| | - Erika Shingen
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
| | - Rina Uehara
- Course of Biotechnology, Graduate School of Sustainable Social Sciences, Tottori University, Tottori 680-8552, Japan
| | - Kunihiro Hongo
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
- Course of Biotechnology, Graduate School of Sustainable Social Sciences, Tottori University, Tottori 680-8552, Japan
- Center for Green Sustainable Chemistry, Faculty of Engineering, Tottori University, Tottori 680-8552, Japan
| | - Yasushi Kawata
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
- Course of Biotechnology, Graduate School of Sustainable Social Sciences, Tottori University, Tottori 680-8552, Japan
- Center for Green Sustainable Chemistry, Faculty of Engineering, Tottori University, Tottori 680-8552, Japan
| | - Tomohiro Mizobata
- Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan
- Course of Biotechnology, Graduate School of Sustainable Social Sciences, Tottori University, Tottori 680-8552, Japan
- Center for Green Sustainable Chemistry, Faculty of Engineering, Tottori University, Tottori 680-8552, Japan
- Correspondence: ; Tel.: +81-857-31-5691
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3
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Kim H, Wu K, Lee C. Stress-Responsive Periplasmic Chaperones in Bacteria. Front Mol Biosci 2021; 8:678697. [PMID: 34046432 PMCID: PMC8144458 DOI: 10.3389/fmolb.2021.678697] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/19/2021] [Indexed: 01/14/2023] Open
Abstract
Periplasmic proteins are involved in a wide range of bacterial functions, including motility, biofilm formation, sensing environmental cues, and small-molecule transport. In addition, a wide range of outer membrane proteins and proteins that are secreted into the media must travel through the periplasm to reach their final destinations. Since the porous outer membrane allows for the free diffusion of small molecules, periplasmic proteins and those that travel through this compartment are more vulnerable to external environmental changes, including those that result in protein unfolding, than cytoplasmic proteins are. To enable bacterial survival under various stress conditions, a robust protein quality control system is required in the periplasm. In this review, we focus on several periplasmic chaperones that are stress responsive, including Spy, which responds to envelope-stress, DegP, which responds to temperature to modulate chaperone/protease activity, HdeA and HdeB, which respond to acid stress, and UgpB, which functions as a bile-responsive chaperone.
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Affiliation(s)
- Hyunhee Kim
- Department of Biological Sciences, Ajou University, Suwon, South Korea
- Molecular, Cellular, and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, United States
| | - Kevin Wu
- Molecular, Cellular, and Developmental Biology, Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, United States
- Department of Biophysics, University of Michigan, Ann Arbor, MI, United States
| | - Changhan Lee
- Department of Biological Sciences, Ajou University, Suwon, South Korea
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4
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Du B, Yang L, Lloyd CJ, Fang X, Palsson BO. Genome-scale model of metabolism and gene expression provides a multi-scale description of acid stress responses in Escherichia coli. PLoS Comput Biol 2019; 15:e1007525. [PMID: 31809503 PMCID: PMC6897400 DOI: 10.1371/journal.pcbi.1007525] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 11/01/2019] [Indexed: 12/20/2022] Open
Abstract
Response to acid stress is critical for Escherichia coli to successfully complete its life-cycle by passing through the stomach to colonize the digestive tract. To develop a fundamental understanding of this response, we established a molecular mechanistic description of acid stress mitigation responses in E. coli and integrated them with a genome-scale model of its metabolism and macromolecular expression (ME-model). We considered three known mechanisms of acid stress mitigation: 1) change in membrane lipid fatty acid composition, 2) change in periplasmic protein stability over external pH and periplasmic chaperone protection mechanisms, and 3) change in the activities of membrane proteins. After integrating these mechanisms into an established ME-model, we could simulate their responses in the context of other cellular processes. We validated these simulations using RNA sequencing data obtained from five E. coli strains grown under external pH ranging from 5.5 to 7.0. We found: i) that for the differentially expressed genes accounted for in the ME-model, 80% of the upregulated genes were correctly predicted by the ME-model, and ii) that these genes are mainly involved in translation processes (45% of genes), membrane proteins and related processes (18% of genes), amino acid metabolism (12% of genes), and cofactor and prosthetic group biosynthesis (8% of genes). We also demonstrated several intervention strategies on acid tolerance that can be simulated by the ME-model. We thus established a quantitative framework that describes, on a genome-scale, the acid stress mitigation response of E. coli that has both scientific and practical uses.
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Affiliation(s)
- Bin Du
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Laurence Yang
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Colton J. Lloyd
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Xin Fang
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Kongens, Lyngby, Denmark
- * E-mail:
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5
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Wu K, Stull F, Lee C, Bardwell JCA. Protein folding while chaperone bound is dependent on weak interactions. Nat Commun 2019; 10:4833. [PMID: 31645566 PMCID: PMC6811625 DOI: 10.1038/s41467-019-12774-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 09/23/2019] [Indexed: 12/31/2022] Open
Abstract
It is generally assumed that protein clients fold following their release from chaperones instead of folding while remaining chaperone-bound, in part because binding is assumed to constrain the mobility of bound clients. Previously, we made the surprising observation that the ATP-independent chaperone Spy allows its client protein Im7 to fold into the native state while continuously bound to the chaperone. Spy apparently permits sufficient client mobility to allow folding to occur while chaperone bound. Here, we show that strengthening the interaction between Spy and a recently discovered client SH3 strongly inhibits the ability of the client to fold while chaperone bound. The more tightly Spy binds to its client, the more it slows the folding rate of the bound client. Efficient chaperone-mediated folding while bound appears to represent an evolutionary balance between interactions of sufficient strength to mediate folding and interactions that are too tight, which tend to inhibit folding. Spy is an ATP independent chaperone that allows folding of its client protein Im7 while continuously bound to Spy. Here the authors employ kinetics measurements to study the folding of another Spy client protein SH3 and find that Spy’s ability to allow a client to fold while bound is inversely related to how strongly it interacts with that client.
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Affiliation(s)
- Kevin Wu
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109-1085, USA.,Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109-1055, USA
| | - Frederick Stull
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109-1085, USA.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1085, USA.,Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008-5413, USA
| | - Changhan Lee
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109-1085, USA.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1085, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109-1085, USA. .,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1085, USA.
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6
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Abstract
The biogenesis of periplasmic and outer membrane proteins (OMPs) in Escherichia coli is assisted by a variety of processes that help with their folding and transport to their final destination in the cellular envelope. Chaperones are macromolecules, usually proteins, that facilitate the folding of proteins or prevent their aggregation without becoming part of the protein's final structure. Because chaperones often bind to folding intermediates, they often (but not always) act to slow protein folding. Protein folding catalysts, on the other hand, act to accelerate specific steps in the protein folding pathway, including disulfide bond formation and peptidyl prolyl isomerization. This review is primarily concerned with E. coli and Salmonella periplasmic and cellular envelope chaperones; it also discusses periplasmic proline isomerization.
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7
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Liu CJ, Lin CT, Chiang JD, Lin CY, Tay YX, Fan LC, Peng KN, Lin CH, Peng HL. RcsB regulation of the YfdX-mediated acid stress response in Klebsiella pneumoniae CG43S3. PLoS One 2019; 14:e0212909. [PMID: 30818355 PMCID: PMC6394985 DOI: 10.1371/journal.pone.0212909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 02/12/2019] [Indexed: 12/31/2022] Open
Abstract
In Klebsiella pneumoniae CG43S3, deletion of the response regulator gene rcsB reduced the capsular polysaccharide amount and survival on exposure to acid stress. A comparison of the pH 4.4-induced proteomes between CG43S3 and CG43S3ΔrcsB revealed numerous differentially expressed proteins and one of them, YfdX, which has recently been reported as a periplasmic protein, was absent in CG43S3ΔrcsB. Acid survival analysis was then conducted to determine its role in the acid stress response. Deletion of yfdX increased the sensitivity of K. pneumoniae CG43S3 to a pH of 2.5, and transforming the mutant with a plasmid carrying yfdX restored the acid resistance (AR) levels. In addition, the effect of yfdX deletion was cross-complemented by the expression of the periplasmic chaperone HdeA. Furthermore, the purified recombinant protein YfdX reduced the acid-induced protein aggregation, suggesting that YfdX as well as HdeA functions as a chaperone. The following promoter activity measurement revealed that rcsB deletion reduced the expression of yfdX after the bacteria were subjected to pH 4.4 adaptation. Western blot analysis also revealed that YfdX production was inhibited by rcsB deletion and only the plasmid expressing RcsB or the nonphosphorylated form of RcsB, RcsBD56A, could restore the YfdX production, and the RcsB-mediated complementation was no longer observed when the sensor kinase RcsD gene was deleted. In conclusion, this is the first study demonstrating that YfdX may be involved in the acid stress response as a periplasmic chaperone and that RcsB positively regulates the acid stress response partly through activation of yfdX expression. Moreover, the phosphorylation status of RcsB may affect the YfdX expression under acidic conditions.
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Affiliation(s)
- Chia-Jui Liu
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Ching-Ting Lin
- School of Chinese Medicine, China Medical University, Taichung, Taiwan, Republic of China
| | - Jo-Di Chiang
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Chen-Yi Lin
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Yen-Xi Tay
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Li-Cheng Fan
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Kuan-Nan Peng
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Chih-Huan Lin
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Hwei-Ling Peng
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
- * E-mail:
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8
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Abstract
The periplasm of Gram-negative bacteria contains a specialized chaperone network that facilitates the transport of unfolded membrane proteins to the outer membrane as its primary functional role. The network, involving the chaperones Skp and SurA as key players and potentially additional chaperones, is indispensable for the survival of the cell. Structural descriptions of the apo forms of these molecular chaperones were initially provided by X-ray crystallography. Subsequently, a combination of experimental biophysical methods including solution NMR spectroscopy provided a detailed understanding of full-length chaperone-client complexes . The data showed that conformational changes and dynamic re-organization of the chaperones upon client binding, as well as client dynamics on the chaperone surface are crucial for function. This chapter gives an overview of the structure-function relationship of the dynamic conformational rearrangements that regulate the functional cycles of the periplasmic molecular chaperones Skp and SurA.
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Affiliation(s)
- Guillaume Mas
- Biozentrum, University of Basel, Klingelbergstrasse 70, Basel, 4056, Switzerland
| | - Johannes Thoma
- Department of Chemistry and Molecular Biology, Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Medicinaregatan 9c, 405 30, Gothenburg, Sweden
| | - Sebastian Hiller
- Biozentrum, University of Basel, Klingelbergstrasse 70, Basel, 4056, Switzerland.
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9
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Yu XC, Hu Y, Ding J, Li H, Jin C. Structural basis and mechanism of the unfolding-induced activation of HdeA, a bacterial acid response chaperone. J Biol Chem 2018; 294:3192-3206. [PMID: 30573682 DOI: 10.1074/jbc.ra118.006398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/17/2018] [Indexed: 11/06/2022] Open
Abstract
The role of protein structural disorder in biological functions has gained increasing attention in the past decade. The bacterial acid-resistant chaperone HdeA belongs to a group of "conditionally disordered" proteins, because it is inactive in its well-structured state and becomes activated via an order-to-disorder transition under acid stress. However, the mechanism for unfolding-induced activation remains unclear because of a lack of experimental information on the unfolded state conformation and the chaperone-client interactions. Herein, we used advanced solution NMR methods to characterize the activated-state conformation of HdeA under acidic conditions and identify its client-binding sites. We observed that the structure of activated HdeA becomes largely disordered and exposes two hydrophobic patches essential for client interactions. Furthermore, using the pH-dependent chemical exchange saturation transfer (CEST) NMR method, we identified three acid-sensitive regions that act as structural locks in regulating the exposure of the two client-binding sites during the activation process, revealing a multistep activation mechanism of HdeA's chaperone function at the atomic level. Our results highlight the role of intrinsic protein disorder in chaperone function and the self-inhibitory role of ordered structures under nonstress conditions, offering new insights for improving our understanding of protein structure-function paradigms.
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Affiliation(s)
- Xing-Chi Yu
- From the College of Chemistry and Molecular Engineering.,Beijing Nuclear Magnetic Resonance Center
| | - Yunfei Hu
- From the College of Chemistry and Molecular Engineering, .,Beijing Nuclear Magnetic Resonance Center
| | - Jienv Ding
- Beijing Nuclear Magnetic Resonance Center.,College of Life Sciences
| | - Hongwei Li
- From the College of Chemistry and Molecular Engineering.,Beijing Nuclear Magnetic Resonance Center
| | - Changwen Jin
- From the College of Chemistry and Molecular Engineering, .,Beijing Nuclear Magnetic Resonance Center.,College of Life Sciences.,Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
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10
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Stull F, Hipp H, Stockbridge RB, Bardwell JCA. In vivo chloride concentrations surge to proteotoxic levels during acid stress. Nat Chem Biol 2018; 14:1051-1058. [PMID: 30323217 PMCID: PMC6193267 DOI: 10.1038/s41589-018-0143-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 08/29/2018] [Indexed: 11/23/2022]
Abstract
To successfully colonize the intestine, bacteria must survive passage through the stomach. The permeability of the outer membrane renders the periplasm of Gram-negative bacteria vulnerable to stomach acid, which inactivates proteins. Here we report that the semipermeable nature of the outer membrane allows the development of a strong Donnan equilibrium across this barrier at low pH. As a result, when bacteria are exposed to conditions that mimic gastric juice, periplasmic chloride concentrations rise to levels that exceed 0.6 M. At these chloride concentrations, proteins readily aggregate in vitro. The acid sensitivity of strains lacking acid-protective chaperones is enhanced by chloride, suggesting that these chaperones protect periplasmic proteins both from acidification and from the accompanying accumulation of chloride. These results illustrate how organisms have evolved chaperones to respond to the substantial chemical threat imposed by otherwise innocuous chloride concentrations that are amplified to proteotoxic levels by low-pH-induced Donnan equilibrium effects.
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Affiliation(s)
- Frederick Stull
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
| | - Hannah Hipp
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Randy B Stockbridge
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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11
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Liu Z, Wang C, Li Y, Zhao C, Li T, Li D, Zhang S, Liu C. Mechanistic insights into the switch of αB-crystallin chaperone activity and self-multimerization. J Biol Chem 2018; 293:14880-14890. [PMID: 30076220 DOI: 10.1074/jbc.ra118.004034] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/25/2018] [Indexed: 12/15/2022] Open
Abstract
αB-Crystallin (αBc) is a small heat shock protein that protects cells against abnormal protein aggregation and disease-related degeneration. αBc is also a major structural protein that forms polydisperse multimers that maintain the liquid-like property of the eye lens. However, the relationship and regulation of the two functions have yet to be explored. Here, by combining NMR spectroscopy and multiple biophysical approaches, we found that αBc uses a conserved β4/β8 surface of the central α-crystallin domain to bind α-synuclein and Tau proteins and prevent them from aggregating into pathological amyloids. We noted that this amyloid-binding surface can also bind the C-terminal IPI motif of αBc, which mediates αBc multimerization and weakens its chaperone activity. We further show that disruption of the IPI binding impairs αBc self-multimerization but enhances its chaperone activity. Our work discloses the structural mechanism underlying the regulation of αBc chaperone activity and self-multimerization and sheds light on the different functions of αBc in antagonizing neurodegeneration and maintaining eye lens liquidity.
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Affiliation(s)
- Zhenying Liu
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China.,University of the Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Chuchu Wang
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China.,University of the Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Yichen Li
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai 200030, China, and
| | - Chunyu Zhao
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China.,University of the Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Tongzhou Li
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China.,University of the Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Dan Li
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai 200030, China, and
| | - Shengnan Zhang
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China,
| | - Cong Liu
- From the Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 26 Qiuyue Road, Shanghai 201210, China,
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12
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Niu X, Ding J, Zhang W, Li Q, Hu Y, Jin C. Residue selective 15N CEST and CPMG experiments for studies of millisecond timescale protein dynamics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 293:47-55. [PMID: 29890486 DOI: 10.1016/j.jmr.2018.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/27/2018] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
Proteins are intrinsically dynamic molecules and undergo exchanges among multiple conformations to perform biological functions. The CPMG relaxation dispersion and CEST experiments are two important solution NMR techniques for characterizing the conformational exchange processes on the millisecond timescale. Traditional pseudo 3D 15N CEST and CPMG experiments have certain limitations in their applications. For example, both experiments have low sensitivity for broadened resonances, and the process of optimizing sample conditions and experimental parameters are often time consuming. To overcome these limitations, we herein present a new set of residue selective 15N CEST and CPMG pulse sequences by employing the Hartmann-Hahn cross-polarization transfer of magnetization in both 1D and 2D schemes. Combined with frequency labeling in the indirect dimension using only a small number of increments, the pulse sequences in the 2D scheme can be applied on resonances in overlapped regions of the 1H-15N HSQC spectrum. The pulse sequences were further applied on several proteins, demonstrating their advantages over the traditional CEST and CPMG experiments under specific circumstances.
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Affiliation(s)
- Xiaogang Niu
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
| | - Jienv Ding
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Life Sciences, Peking University, Beijing, China
| | - Wenbo Zhang
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Life Sciences, Peking University, Beijing, China
| | - Qianwen Li
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Life Sciences, Peking University, Beijing, China
| | - Yunfei Hu
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Changwen Jin
- Beijing Nuclear Magnetic Resonance Center, Peking University, Beijing, China; College of Chemistry and Molecular Engineering, Peking University, Beijing, China; College of Life Sciences, Peking University, Beijing, China.
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13
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Voth W, Jakob U. Stress-Activated Chaperones: A First Line of Defense. Trends Biochem Sci 2017; 42:899-913. [PMID: 28893460 DOI: 10.1016/j.tibs.2017.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 10/18/2022]
Abstract
Proteins are constantly challenged by environmental stress conditions that threaten their structure and function. Especially problematic are oxidative, acid, and severe heat stress which induce very rapid and widespread protein unfolding and generate conditions that make canonical chaperones and/or transcriptional responses inadequate to protect the proteome. We review here recent advances in identifying and characterizing stress-activated chaperones which are inactive under non-stress conditions but become potent chaperones under specific protein-unfolding stress conditions. We discuss the post-translational mechanisms by which these chaperones sense stress, and consider the role that intrinsic disorder plays in their regulation and function. We examine their physiological roles under both non-stress and stress conditions, their integration into the cellular proteostasis network, and their potential as novel therapeutic targets.
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Affiliation(s)
- Wilhelm Voth
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular Biology, Universitätsmedizin Göttingen, 37073 Göttingen, Germany
| | - Ursula Jakob
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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Socher E, Sticht H. Probing the Structure of the Escherichia coli Periplasmic Proteins HdeA and YmgD by Molecular Dynamics Simulations. J Phys Chem B 2016; 120:11845-11855. [PMID: 27787971 DOI: 10.1021/acs.jpcb.6b06091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
HdeA and YmgD are structurally homologous proteins in the periplasm of Escherichia coli. HdeA has been shown to represent an acid-activated chaperone, whereas the function of YmgD has not yet been characterized. We performed pH-titrating molecular dynamics simulations (pHtMD) to investigate the structural changes of both proteins and to assess whether YmgD may also exhibit an unfolding behavior similar to that of HdeA. The unfolding pathway of HdeA includes partially unfolded dimer structures, which represent a prerequisite for subsequent dissociation. In contrast to the coupled unfolding and dissociation of HdeA, YmgD displays dissociation of the folded subunits, and the subunits do not undergo significant unfolding even at low pH values. The differences in subunit stability between HdeA and YmgD may be explained by the structural features of helix D, which represents the starting point of unfolding in HdeA. In summary, the present study suggests that YmgD either is not an acid-activated chaperone or, at least, does not require unfolding for activation.
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Affiliation(s)
- Eileen Socher
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Fahrstraße 17, 91054 Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Fahrstraße 17, 91054 Erlangen, Germany
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