1
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Yoo H, Bard JA, Pilipenko E, Drummond DA. Chaperones directly and efficiently disperse stress-triggered biomolecular condensates. Mol Cell 2022; 82:741-755.e11. [PMID: 35148816 PMCID: PMC8857057 DOI: 10.1016/j.molcel.2022.01.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/30/2021] [Accepted: 01/06/2022] [Indexed: 12/28/2022]
Abstract
Stresses such as heat shock trigger the formation of protein aggregates and the induction of a disaggregation system composed of molecular chaperones. Recent work reveals that several cases of apparent heat-induced aggregation, long thought to be the result of toxic misfolding, instead reflect evolved, adaptive biomolecular condensation, with chaperone activity contributing to condensate regulation. Here we show that the yeast disaggregation system directly disperses heat-induced biomolecular condensates of endogenous poly(A)-binding protein (Pab1) orders of magnitude more rapidly than aggregates of the most commonly used misfolded model substrate, firefly luciferase. Beyond its efficiency, heat-induced condensate dispersal differs from heat-induced aggregate dispersal in its molecular requirements and mechanistic behavior. Our work establishes a bona fide endogenous heat-induced substrate for long-studied heat shock proteins, isolates a specific example of chaperone regulation of condensates, and underscores needed expansion of the proteotoxic interpretation of the heat shock response to encompass adaptive, chaperone-mediated regulation.
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Affiliation(s)
- Haneul Yoo
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Jared A.M. Bard
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Evgeny Pilipenko
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - D. Allan Drummond
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA,Department of Medicine, Section of Genetic Medicine, The University of Chicago, Chicago, IL, 60637, USA,Lead Contact,Correspondence: (D.A.D.)
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2
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Kim H, Park J, Lim S, Jun SH, Jung M, Roh SH. Cryo-EM structures of GroEL:ES 2 with RuBisCO visualize molecular contacts of encapsulated substrates in a double-cage chaperonin. iScience 2022; 25:103704. [PMID: 35036883 PMCID: PMC8749442 DOI: 10.1016/j.isci.2021.103704] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/12/2021] [Accepted: 12/23/2021] [Indexed: 10/24/2022] Open
Abstract
The GroEL/GroES chaperonin system assists the folding of many proteins, through conformational transitions driven by ATP hydrolysis. Although structural information about bullet-shaped GroEL:ES1 complexes has been extensively reported, the substrate interactions of another functional complex, the football-shaped GroEL:ES2, remain elusive. Here, we report single-particle cryo-EM structures of reconstituted wild-type GroEL:ES2 complexes with a chemically denatured substrate, ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO). Our structures demonstrate that native-like folded RuBisCO density is captured at the lower part of the GroEL chamber and that GroEL's bulky hydrophobic residues Phe281, Tyr360, and Phe44 contribute to direct contact with RuBisCO density. In addition, our analysis found that GroEL:ES2 can be occupied by two substrates simultaneously, one in each chamber. Together, these observations provide insights to the football-shaped GroEL:ES2 complex as a functional state to assist the substrate folding with visualization.
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Affiliation(s)
- Hyunmin Kim
- School of Biology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Junsun Park
- School of Biology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Seyeon Lim
- School of Biology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung-Hoon Jun
- Korea Basic Science Institute, Ochang 28119, Republic of Korea
| | - Mingyu Jung
- School of Biology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Soung-Hun Roh
- School of Biology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
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3
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Abstract
This chronologue seeks to document the discovery and development of an understanding of oligomeric ring protein assemblies known as chaperonins that assist protein folding in the cell. It provides detail regarding genetic, physiologic, biochemical, and biophysical studies of these ATP-utilizing machines from both in vivo and in vitro observations. The chronologue is organized into various topics of physiology and mechanism, for each of which a chronologic order is generally followed. The text is liberally illustrated to provide firsthand inspection of the key pieces of experimental data that propelled this field. Because of the length and depth of this piece, the use of the outline as a guide for selected reading is encouraged, but it should also be of help in pursuing the text in direct order.
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4
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Motojima F, Fujii K, Yoshida M. Chaperonin facilitates protein folding by avoiding initial polypeptide collapse. J Biochem 2018; 164:369-379. [PMID: 30053017 PMCID: PMC6190516 DOI: 10.1093/jb/mvy061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 07/12/2018] [Indexed: 11/14/2022] Open
Abstract
Chaperonins assist folding of many cellular proteins, including essential proteins for cell viability. However, it remains unclear how chaperonin-assisted folding is different from spontaneous folding. Chaperonin GroEL/GroES facilitates folding of denatured protein encapsulated in its central cage but the denatured protein often escapes from the cage to the outside during reaction. Here, we show evidence that the in-cage-folding and the escape occur diverging from the same intermediate complex in which polypeptide is tethered loosely to the cage and partly protrudes out of the cage. Furthermore, denatured proteins in the chaperonin cage are kept in more extended conformation than those initially formed in spontaneous folding. We propose that the formation of tethered intermediate of polypeptide is necessary to prevent polypeptide collapse at the expense of polypeptide escape. The tethering of polypeptide would allow freely mobile portions of tethered polypeptide to fold segmentally.
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Affiliation(s)
- Fumihiro Motojima
- Department of Molecular Biosciences, Kyoto Sangyo University Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, Japan
| | - Katsuya Fujii
- Department of Molecular Biosciences, Kyoto Sangyo University Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
| | - Masasuke Yoshida
- Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, Japan
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5
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Willems K, Van Meervelt V, Wloka C, Maglia G. Single-molecule nanopore enzymology. Philos Trans R Soc Lond B Biol Sci 2018. [PMID: 28630164 DOI: 10.1098/rstb.2016.0230] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Biological nanopores are a class of membrane proteins that open nanoscale water conduits in biological membranes. When they are reconstituted in artificial membranes and a bias voltage is applied across the membrane, the ionic current passing through individual nanopores can be used to monitor chemical reactions, to recognize individual molecules and, of most interest, to sequence DNA. In addition, a more recent nanopore application is the analysis of single proteins and enzymes. Monitoring enzymatic reactions with nanopores, i.e. nanopore enzymology, has the unique advantage that it allows long-timescale observations of native proteins at the single-molecule level. Here, we describe the approaches and challenges in nanopore enzymology.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Kherim Willems
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.,Department of Life Sciences and Imaging, IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - Veerle Van Meervelt
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.,Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Carsten Wloka
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Giovanni Maglia
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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6
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Replacement of GroEL in Escherichia coli by the Group II Chaperonin from the Archaeon Methanococcus maripaludis. J Bacteriol 2016; 198:2692-700. [PMID: 27432832 PMCID: PMC5019054 DOI: 10.1128/jb.00317-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/23/2016] [Indexed: 12/21/2022] Open
Abstract
Chaperonins are required for correct folding of many proteins. They exist in two phylogenetic groups: group I, found in bacteria and eukaryotic organelles, and group II, found in archaea and eukaryotic cytoplasm. The two groups, while homologous, differ significantly in structure and mechanism. The evolution of group II chaperonins has been proposed to have been crucial in enabling the expansion of the proteome required for eukaryotic evolution. In an archaeal species that expresses both groups of chaperonins, client selection is determined by structural and biochemical properties rather than phylogenetic origin. It is thus predicted that group II chaperonins will be poor at replacing group I chaperonins. We have tested this hypothesis and report here that the group II chaperonin from Methanococcus maripaludis (Mm-cpn) can partially functionally replace GroEL, the group I chaperonin of Escherichia coli. Furthermore, we identify and characterize two single point mutations in Mm-cpn that have an enhanced ability to replace GroEL function, including one that allows E. coli growth after deletion of the groEL gene. The biochemical properties of the wild-type and mutant Mm-cpn proteins are reported. These data show that the two groups are not as functionally diverse as has been thought and provide a novel platform for genetic dissection of group II chaperonins. IMPORTANCE The two phylogenetic groups of the essential and ubiquitous chaperonins diverged approximately 3.7 billion years ago. They have similar structures, with two rings of multiple subunits, and their major role is to assist protein folding. However, they differ with regard to the details of their structure, their cofactor requirements, and their reaction cycles. Despite this, we show here that a group II chaperonin from a methanogenic archaeon can partially substitute for the essential group I chaperonin GroEL in E. coli and that we can easily isolate mutant forms of this chaperonin with further improved functionality. This is the first demonstration that these two groups, despite the long time since they diverged, still overlap significantly in their functional properties.
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7
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Okamoto T, Ishida R, Yamamoto H, Tanabe-Ishida M, Haga A, Takahashi H, Takahashi K, Goto D, Grave E, Itoh H. Functional structure and physiological functions of mammalian wild-type HSP60. Arch Biochem Biophys 2015; 586:10-9. [PMID: 26427351 DOI: 10.1016/j.abb.2015.09.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/20/2015] [Accepted: 09/25/2015] [Indexed: 11/16/2022]
Abstract
The Chaperonins comprise a family of molecular chaperones having a double-ring structure and similar sequence homology. These proteins play an essential role in biological reactions that mediate the folding of newly synthesized polypeptides and partially denatured proteins. In the prokaryotic group I chaperonins, structural and reaction cycle analyses of GroEL and its co-chaperone GroES have been performed in detail. While in eukaryotes, there have been limited reports analyzing the group I chaperonin HSP60 and its co-chaperone HSP10. In the present study, we purified the wild type HSP60 from porcine liver and investigated the interaction between HSP60 and HSP10, including conformation and physiological relationships. Based on the results of transmission electron microscopy, native PAGE, and gel filtration column chromatography, the wild type HSP60 displayed a heptameric single-ring structure in the absence of ATP. In contrast, HSP60 formed mainly a "football-type" complex with HSP10 in the presence of ATP and mediated the refolding of denatured substrate protein. The functional conformation cycle of the purified mammalian HSP60 is distinct from the cycle of the prokaryotic GroEL/GroES chaperonin.
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Affiliation(s)
- Tomoya Okamoto
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Ryuichi Ishida
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan; Department of Biomolecular Science and Engineering, The Institute of Scientific and Industrial Research, Osaka University, 1-1 Yamadagaoka Suita, Osaka 565-0871, Japan
| | - Hiroshi Yamamoto
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Masako Tanabe-Ishida
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Asami Haga
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Hiroki Takahashi
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Kyosuke Takahashi
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Daisuke Goto
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Ewa Grave
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Hideaki Itoh
- Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
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8
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Productive folding of a tethered protein in the chaperonin GroEL-GroES cage. Biochem Biophys Res Commun 2015; 466:72-5. [PMID: 26325470 DOI: 10.1016/j.bbrc.2015.08.108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/24/2015] [Indexed: 11/22/2022]
Abstract
Many proteins in bacterial cells fold in the chaperonin cage made of the central cavity of GroEL capped by GroES. Recent studies indicate that the polypeptide in the cage spends the most time as a state tethered dynamically to the GroEL/GroES interface region, in which folding occurs in the polypeptide segments away from the tethered site (F. Motojima & M. Yoshida, EMBO J. (2010) 29, 4008-4019). In support of this, we show here that a polypeptide in the cage tethered covalently to an appropriate site in the GroEL/GroES interface region can fold to a near-native structure.
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9
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Abstract
Protein folding is a biological process that is essential for the proper functioning of proteins in all living organisms. In cells, many proteins require the assistance of molecular chaperones for their folding. Chaperonins belong to a class of molecular chaperones that have been extensively studied. However, the mechanism by which a chaperonin mediates the folding of proteins is still controversial. Denatured proteins are folded in the closed chaperonin cage, leading to the assumption that denatured proteins are completely encapsulated inside the chaperonin cage. In contrast to the assumption, we recently found that denatured protein interacts with hydrophobic residues at the subunit interfaces of the chaperonin, and partially protrude out of the cage. In this review, we will explain our recent results and introduce our model for the mechanism by which chaperonins accelerate protein folding, in view of recent findings.
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Affiliation(s)
- Fumihiro Motojima
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan
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10
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Gupta AJ, Haldar S, Miličić G, Hartl FU, Hayer-Hartl M. Active Cage Mechanism of Chaperonin-Assisted Protein Folding Demonstrated at Single-Molecule Level. J Mol Biol 2014; 426:2739-54. [DOI: 10.1016/j.jmb.2014.04.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 04/16/2014] [Accepted: 04/21/2014] [Indexed: 01/19/2023]
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11
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Weaver J, Rye HS. The C-terminal tails of the bacterial chaperonin GroEL stimulate protein folding by directly altering the conformation of a substrate protein. J Biol Chem 2014; 289:23219-23232. [PMID: 24970895 DOI: 10.1074/jbc.m114.577205] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many essential cellular proteins fold only with the assistance of chaperonin machines like the GroEL-GroES system of Escherichia coli. However, the mechanistic details of assisted protein folding by GroEL-GroES remain the subject of ongoing debate. We previously demonstrated that GroEL-GroES enhances the productive folding of a kinetically trapped substrate protein through unfolding, where both binding energy and the energy of ATP hydrolysis are used to disrupt the inhibitory misfolded states. Here, we show that the intrinsically disordered yet highly conserved C-terminal sequence of the GroEL subunits directly contributes to substrate protein unfolding. Interactions between the C terminus and the non-native substrate protein alter the binding position of the substrate protein on the GroEL apical surface. The C-terminal tails also impact the conformational state of the substrate protein during capture and encapsulation on the GroEL ring. Importantly, removal of the C termini results in slower overall folding, reducing the fraction of the substrate protein that commits quickly to a productive folding pathway and slowing several kinetically distinct folding transitions that occur inside the GroEL-GroES cavity. The conserved C-terminal tails of GroEL are thus important for protein folding from the beginning to the end of the chaperonin reaction cycle.
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Affiliation(s)
- Jeremy Weaver
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843
| | - Hays S Rye
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843.
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12
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Weber JK, Pande VS. Functional understanding of solvent structure in GroEL cavity through dipole field analysis. J Chem Phys 2013; 138:165101. [PMID: 23635172 DOI: 10.1063/1.4801942] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Solvent plays a ubiquitous role in all biophysical phenomena. Yet, just how the molecular nature of water impacts processes in biology remains an important question. While one can simulate the behavior of water near biomolecules such as proteins, it is challenging to gauge the potential structural role solvent plays in mediating both kinetic and equilibrium processes. Here, we propose an analysis scheme for understanding the nature of solvent structure at a local level. We first calculate coarse-grained dipole vector fields for an explicitly solvated system simulated through molecular dynamics. We then analyze correlations between these vector fields to characterize water structure under biologically relevant conditions. In applying our method to the interior of the wild type chaperonin complex GroEL+ES, along with nine additional mutant GroEL complexes, we find that dipole field correlations are strongly related to chaperonin function.
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Affiliation(s)
- Jeffrey K Weber
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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13
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Nuclear magnetic resonance approaches for characterizing interactions between the bacterial chaperonin GroEL and unstructured proteins. J Biosci Bioeng 2013; 116:160-4. [DOI: 10.1016/j.jbiosc.2013.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 02/05/2013] [Accepted: 02/19/2013] [Indexed: 12/18/2022]
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14
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Yagi-Utsumi M, Kunihara T, Nakamura T, Uekusa Y, Makabe K, Kuwajima K, Kato K. NMR characterization of the interaction of GroEL with amyloid β as a model ligand. FEBS Lett 2013; 587:1605-9. [PMID: 23603391 DOI: 10.1016/j.febslet.2013.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/14/2013] [Accepted: 04/05/2013] [Indexed: 10/26/2022]
Abstract
Here we report an NMR study on the substrate interaction modes of GroEL using amyloid β (Aβ) as a model ligand. We found that GroEL could suppress Aβ(1-40) amyloid formation by interacting with its two hydrophobic segments Leu17-Ala21 and Ala30-Val36, which involve key residues in fibril formation. The binding site of Aβ(1-40) was mapped on a pair of α-helices located in the GroEL apical domain. These results provide insights into chaperonin recognition of amyloidogenic proteins of pathological interest.
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Affiliation(s)
- Maho Yagi-Utsumi
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Japan
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15
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Chandak MS, Nakamura T, Makabe K, Takenaka T, Mukaiyama A, Chaudhuri TK, Kato K, Kuwajima K. The H/D-exchange kinetics of the Escherichia coli co-chaperonin GroES studied by 2D NMR and DMSO-quenched exchange methods. J Mol Biol 2013; 425:2541-60. [PMID: 23583779 DOI: 10.1016/j.jmb.2013.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/29/2013] [Accepted: 04/05/2013] [Indexed: 11/18/2022]
Abstract
We studied hydrogen/deuterium-exchange reactions of peptide amide protons of GroES using two different techniques: (1) two-dimensional (1)H-(15)N transverse-optimized NMR spectroscopy and (2) the dimethylsulfoxide-quenched hydrogen-exchange method combined with conventional (1)H-(15)N heteronuclear single quantum coherence spectroscopy. By using these techniques together with direct heteronuclear single quantum coherence experiments, we quantitatively evaluated the exchange rates for 33 out of the 94 peptide amide protons of GroES and their protection factors, and for the remaining 61 residues, we obtained the lower limits of the exchange rates. The protection factors of the most highly protected amide protons were on the order of 10(6)-10(7), and the values were comparable in magnitude to those observed in typical small globular proteins, but the number of the highly protected amide protons with a protection factor larger than 10(6) was only 10, significantly smaller than the numbers reported for the small globular proteins, indicating that significant portions of free heptameric GroES are flexible and natively unfolded. The highly protected amino acid residues with a protection factor larger than 10(5) were mainly located in three β-strands that form the hydrophobic core of GroES, while the residues in a mobile loop (residues 17-34) were not highly protected. The protection factors of the most highly protected amide protons were orders of magnitude larger than the value expected from the equilibrium unfolding parameters previously reported, strongly suggesting that the equilibrium unfolding of GroES is more complicated than a simple two-state or three-state mechanism and may involve more than a single intermediate.
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Affiliation(s)
- Mahesh S Chandak
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
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