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Walker TE, Shirzadeh M, Sun HM, McCabe JW, Roth A, Moghadamchargari Z, Clemmer DE, Laganowsky A, Rye H, Russell DH. Temperature Regulates Stability, Ligand Binding (Mg 2+ and ATP), and Stoichiometry of GroEL-GroES Complexes. J Am Chem Soc 2022; 144:2667-2678. [PMID: 35107280 PMCID: PMC8939001 DOI: 10.1021/jacs.1c11341] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chaperonins are nanomachines that harness ATP hydrolysis to power and catalyze protein folding, a chemical action that is directly linked to the maintenance of cell function through protein folding/refolding and assembly. GroEL and the GroEL-GroES complex are archetypal examples of such protein folding machines. Here, variable-temperature electrospray ionization (vT-ESI) native mass spectrometry is used to delineate the effects of solution temperature and ATP concentrations on the stabilities of GroEL and GroEL-GroES complexes. The results show clear evidence for destabilization of both GroEL14 and GroES7 at temperatures of 50 and 45 °C, respectively, substantially below the previously reported melting temperature (Tm ∼ 70 °C). This destabilization is accompanied by temperature-dependent reaction products that have previously unreported stoichiometries, viz. GroEL14-GroESy-ATPn, where y = 1, 2, 8 and n = 0, 1, 2, 8, that are also dependent on Mg2+ and ATP concentrations. Variable-temperature native mass spectrometry reveals new insights about the stability of GroEL in response to temperature effects: (i) temperature-dependent ATP binding to GroEL; (ii) effects of temperature as well as Mg2+ and ATP concentrations on the stoichiometry of the GroEL-GroES complex, with Mg2+ showing greater effects compared to ATP; and (iii) a change in the temperature-dependent stoichiometries of the GroEL-GroES complex (GroEL14-GroES7 vs GroEL14-GroES8) between 24 and 40 °C. The similarities between results obtained by using native MS and cryo-EM [Clare et al. An expanded protein folding cage in the GroEL-gp31 complex. J. Mol. Biol. 2006, 358, 905-911; Ranson et al. Allosteric signaling of ATP hydrolysis in GroEL-GroES complexes.Nat. Struct. Mol. Biol. 2006, 13, 147-152] underscore the utility of native MS for investigations of molecular machines as well as identification of key intermediates involved in the chaperonin-assisted protein folding cycle.
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Affiliation(s)
- Thomas E. Walker
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Mehdi Shirzadeh
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - He Mirabel Sun
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jacob W. McCabe
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Andrew Roth
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Zahra Moghadamchargari
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David E. Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Hays Rye
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - David H. Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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2
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Pasta SY, Raman B, Ramakrishna T, Rao CM. Role of the Conserved SRLFDQFFG Region of α-Crystallin, a Small Heat Shock Protein. J Biol Chem 2003; 278:51159-66. [PMID: 14532291 DOI: 10.1074/jbc.m307523200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Small heat shock proteins (sHsps) are necessary for several cellular functions and in stress tolerance. Most sHsps are oligomers; intersubunit interactions leading to changes in oligomeric structure and exposure of specific regions may modulate their functioning. Many sHsps, including alpha A- and alpha B-crystallin, contain a well conserved SRLFDQFFG sequence motif in the N-terminal region. Sequence-based prediction shows that it exhibits helical propensity with amphipathic character, suggesting that it plays a critical role in the structure and function of alpha-crystallins. In order to investigate the role of this motif in the structure and function of sHsps, we have made constructs deleting this sequence from alpha A- and alpha B-crystallin, overexpressed, purified, and studied these engineered proteins. Circular dichroism spectroscopic studies show changes in tertiary and secondary structure on deletion of the sequence. Glycerol density gradient centrifugation and dynamic light scattering studies show that the multimeric size of the mutant proteins is significantly reduced, indicating a role for this motif in higher order organization of the subunits. Both deletion mutants exhibit similar oligomeric size and increased chaperone-like activity. Urea-induced denaturation study shows that the SRLFDQFFG sequence contributes significantly to the structural stability. Fluorescence resonance energy transfer studies show that the rate of exchange of the subunits in the alpha Adel-crystallin oligomer is higher compared with that in the alpha A-crystallin oligomer, suggesting that this region contributes to the oligomer dynamics in addition to the higher order assembly and structural stability. Thus, our study shows that the SRLFDQFFG sequence is one of the critical motifs in structure-function regulation of alpha A- and alpha B-crystallin.
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3
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Raman B, Siva Kumar LV, Ramakrishna T, Mohan Rao C. Redox-regulated chaperone function and conformational changes of Escherichia coli Hsp33. FEBS Lett 2001; 489:19-24. [PMID: 11231006 DOI: 10.1016/s0014-5793(01)02074-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have studied the chaperone activity and conformation of Escherichia coli heat shock protein (Hsp)33, whose activity is known to be switched on by oxidative conditions. While oxidized Hsp33 completely prevents the heat-induced aggregation of zeta-crystallin at 42 degrees C at a ratio of 1:1 (w/w), the reduced form exhibits only a marginal effect on the aggregation. Far UV-circular dichroism (CD) spectra show that reduced Hsp33 contains a significant alpha-helical component. Oxidation results in significant changes in the far UV-CD spectrum. Near UV-CD spectra show changes in tertiary structural packing upon oxidation. Polarity-sensitive fluorescent probes report enhanced hydrophobic surfaces in the oxidized Hsp33. Our studies show that the oxidative activation of the chaperone function of Hsp33 involves observable conformational changes accompanying increased exposure of hydrophobic pockets.
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Affiliation(s)
- B Raman
- Centre for Cellular and Molecular Biology, 500 007, Hyderabad, India
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4
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Hammarström P, Persson M, Owenius R, Lindgren M, Carlsson U. Protein substrate binding induces conformational changes in the chaperonin GroEL. A suggested mechanism for unfoldase activity. J Biol Chem 2000; 275:22832-8. [PMID: 10811634 DOI: 10.1074/jbc.m000649200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chaperonins are molecules that assist proteins during folding and protect them from irreversible aggregation. We studied the chaperonin GroEL and its interaction with the enzyme human carbonic anhydrase II (HCA II), which induces unfolding of the enzyme. We focused on conformational changes that occur in GroEL during formation of the GroEL-HCA II complex. We measured the rate of GroEL cysteine reactivity toward iodo[2-(14)C]acetic acid and found that the cysteines become more accessible during binding of a cysteine free mutant of HCA II. Spin labeling of GroEL with N-(1-oxyl-2,2,5, 5-tetramethyl-3-pyrrolidinyl)iodoacetamide revealed that this additional binding occurred because buried cysteine residues become accessible during HCA II binding. In addition, a GroEL variant labeled with 6-iodoacetamidofluorescein exhibited decreased fluorescence anisotropy upon HCA II binding, which resembles the effect of GroES/ATP binding. Furthermore, by producing cysteine-modified GroEL with the spin label N-(1-oxyl-2,2,5, 5-tetramethyl-3-pyrrolidinyl)iodoacetamide and the fluorescent label 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid, we detected increases in spin-label mobility and fluorescence intensity in GroEL upon HCA II binding. Together, these results show that conformational changes occur in the chaperonin as a consequence of protein substrate binding. Together with previous results on the unfoldase activity of GroEL, we suggest that the chaperonin opens up as the substrate protein binds. This opening mechanism may induce stretching of the protein, which would account for reported unfoldase activity of GroEL and might explain how GroEL can actively chaperone proteins larger than HCA II.
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Affiliation(s)
- P Hammarström
- IFM Department of Chemistry and Chemical Physics, Linköping University, S-581 83 Linköping, Sweden
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5
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Shearstone JR, Baneyx F. Biochemical characterization of the small heat shock protein IbpB from Escherichia coli. J Biol Chem 1999; 274:9937-45. [PMID: 10187768 DOI: 10.1074/jbc.274.15.9937] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli IbpB was overexpressed in a strain carrying a deletion in the chromosomal ibp operon and purified by refolding. Under our experimental conditions, IbpB exhibited pronounced size heterogeneity. Basic oligomers, roughly spherical and approximately 15 nm in diameter, interacted to form larger particles in the 100-200-nm range, which themselves associated to yield loose aggregates of micrometer size. IbpB suppressed the thermal aggregation of model proteins in a concentration-dependent manner, and its CD spectrum was consistent with a mostly beta-pleated secondary structure. Incubation at high temperatures led to a partial loss of secondary structure, the progressive exposure of tryptophan residues to the solvent, the dissociation of high molecular mass aggregates into approximately 600-kDa oligomers, and an increase in surface hydrophobicity. Structural changes were reversible between 37 and 55 degrees C, and, up to 55 degrees C, hydrophobic sites were reburied upon cooling. IbpB exhibited a biphasic unfolding trend upon guanidine hydrochloride (GdnHCl) treatment and underwent comparable conformational changes upon melting and during the first GdnHCl-induced transition. However, hydrophobicity decreased with increasing GdnHCl concentrations, suggesting that efficient exposure of structured hydrophobic sites involves denaturant-sensitive structural features. By contrast, IbpB hydrophobicity rose at high NaCl concentrations and increased further at high temperatures. Our results support a model in which temperature-driven conformational changes lead to the reversible exposure of normally shielded binding sites for nonnative proteins and suggest that both hydrophobicity and charge context may determine substrate binding to IbpB.
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Affiliation(s)
- J R Shearstone
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, USA
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6
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Galán A, Llorca O, Valpuesta JM, Pérez-Pérez J, Carrascosa JL, Menéndez M, Bañuelos S, Muga A. ATP hydrolysis induces an intermediate conformational state in GroEL. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:347-55. [PMID: 9914513 DOI: 10.1046/j.1432-1327.1999.00045.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The conformational properties of the molecular chaperone GroEL in the presence of ATP, its non-hydrolyzable analog 5'-adenylimidodiphosphate (AMP-PNP), and ADP have been analyzed by differential scanning calorimetry (DSC), Fourier-transform infra-red (FT-IR) and fluorescence spectroscopy. Nucleotide binding to one ring promotes a decrease in the Tm value of the GroEL thermal transition that is reversed when both rings are filled with nucleotide, indicating that the sequential occupation of the two protein rings by these nucleotides has different effects on the GroEL thermal denaturation process. In addition, ATP induces a conformational change in GroEL characterized by (a) the appearance of a reversible low temperature endotherm in the DSC profiles of the protein, and (b) an enhanced binding of the hydrophobic probe 8-anilino-naphthalene-1-sulfonate (ANS), which strictly depends on ATP hydrolysis. The similar sensitivity to K+ of the temperature range where activation of the GroEL ATPase activity, the low temperature endotherm, and the increase of the ANS fluorescence are abserved strongly indicates the existence of a conformational state of GroEL during ATP hydrolysis, different from that generated on ADP or AMP-PNP binding. To achieve this intermediate conformation, GroEL mainly modifies its tertiary and quaternary structures, leading to an increased exposure of hydrophobic surfaces, with minor rearrangements of its secondary structure.
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Affiliation(s)
- A Galán
- Department de Bioquímica y Biología Molecular, Unidad asociada al CSIC, Universidad del París Vaco, Bilbao, Spain
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7
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Rao CM, Raman B, Ramakrishna T, Rajaraman K, Ghosh D, Datta S, Trivedi VD, Sukhaswami MB. Structural perturbation of alpha-crystallin and its chaperone-like activity. Int J Biol Macromol 1998; 22:271-81. [PMID: 9650082 DOI: 10.1016/s0141-8130(98)00025-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
alpha-Crystallin is a multimeric lenticular protein that has recently been shown to be expressed in several non-lenticular tissues as well. It is shown to prevent aggregation of non-native proteins as a molecular chaperone. By using a non-thermal aggregation model, we could show that this process is temperature-dependent. We investigated the chaperone-like activity of alpha-crystallin towards photo-induced aggregation of gamma-crystallin, aggregation of insulin and on the refolding induced aggregation of beta- and gamma-crystallins. We observed that alpha-crystallin could prevent photo-aggregation of gamma-crystallin and this chaperone-like activity of alpha-crystallin is enhanced several fold at temperatures above 30 degrees C. This enhancement parallels the exposure of its hydrophobic surfaces as a function of temperature, probed using hydrophobic fluorescent probes such as pyrene and 8-anilinonaphthalene-1-sulfonate. We, therefore, concluded that alpha-crystallin prevents the aggregation of other proteins by providing appropriately placed hydrophobic surfaces; a structural transition above 30 degrees C involving enhanced or re-organized hydrophobic surfaces of alpha-crystallin is important for its chaperone-like activity. We also addressed the issue of conformational aspects of target proteins and found that their aggregation prone molten globule states bind to alpha-crystallin. We trace these developments and discuss some new lines that suggest the role of tertiary structural aspects in the chaperone process.
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Affiliation(s)
- C M Rao
- Centre for Cellular and Molecular Biology, Hyderabad, India.
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8
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Raman B, Rao CM. Chaperone-like activity and temperature-induced structural changes of alpha-crystallin. J Biol Chem 1997; 272:23559-64. [PMID: 9295293 DOI: 10.1074/jbc.272.38.23559] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
alpha-Crystallin is known to exhibit chaperone-like activity. We have studied its chaperone-like activity toward the aggregation of betaL-crystallin upon refolding of this protein from its unfolded state in guanidinium chloride. The chaperone-like activity of alpha-crystallin is less pronounced below 30 degrees C and is enhanced above this temperature. The plot of percentage protection as a function of temperature shows two transitions; one at 30 degrees C and another at around 55 degrees C. We have performed steady state fluorescence, fluorescence polarization, fluorescence quenching, circular dichroism, sedimentation analysis, and gel filtration chromatography to probe the temperature-induced structural changes of alpha-crystallin. Our results show that at above 50 degrees C, alpha-crystallin undergoes a transition to a multimeric molten globule-like state. Above 30 degrees C, a minor but detectable perturbation in its tertiary structure occurs that might lead to the observed exposure of its hydrophobic surfaces. These results support our earlier hypothesis that alpha-crystallin prevents the aggregation of other proteins by providing appropriately placed hydrophobic surfaces; a structural transition above 30 degrees C involving enhanced or reorganized hydrophobic surfaces of alpha-crystallin is important for its chaperone-like activity. It is possible that a structural alteration induced by temperature forms a part of the general mechanism of chaperone function, because they are required to function more effectively at nonpermissible temperatures.
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Affiliation(s)
- B Raman
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
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9
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Churchich JE. Conformational changes at the nucleotide binding of GroEL induced by binding of protein substrates. Luminescence studies. J Biol Chem 1997; 272:19645-8. [PMID: 9242617 DOI: 10.1074/jbc.272.32.19645] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
2'-Deoxy-3'-anthraniloyl adenosine-5-triphosphate (ANT-dATP) coordinated to Tb3+ was used as an environmentally sensitive probe of the nucleotide-binding site of GroEL. Tb3+.ANT-dATP recognizes the nucleotide-binding site of GroEL and inhibits ATPase activity. Sensitized luminescence, arising from resonance energy transfer from the anthraniloyl moiety to Tb3+, is substantially enhanced in the presence of GroEL. Binding of denatured mitochondrial malate dehydrogenase to the apical domain of GroEL causes a red shift in the fluorescence emitted by anthraniloyl and further enhancement in the phosphorescence emitted by Tb3+ upon excitation at 320 nm. It is suggested that binding of the protein substrate initiates domain movement, which is extended to the nucleotide-binding site. The luminescence results are discussed in reference to the structure of GroEL derived from x-ray crystallographic studies.
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Affiliation(s)
- J E Churchich
- Department of Biochemistry, University of Tennessee, Knoxville, Tennessee 37996-0840, USA
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10
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Török Z, Horváth I, Goloubinoff P, Kovács E, Glatz A, Balogh G, Vígh L. Evidence for a lipochaperonin: association of active protein-folding GroESL oligomers with lipids can stabilize membranes under heat shock conditions. Proc Natl Acad Sci U S A 1997; 94:2192-7. [PMID: 9122170 PMCID: PMC20063 DOI: 10.1073/pnas.94.6.2192] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
During heat shock, structural changes in proteins and membranes may lead to cell death. While GroE and other chaperone proteins are involved in the prevention of stress-induced protein aggregation and in the recovery of protein structures, a mechanism for short-term membrane stabilization during stress remains to be established. We found that GroEL chaperonin can associate with model lipid membranes. Binding was apparently governed by the composition and the physical state of the host bilayer. Limited proteolysis of GroEL oligomers by proteinase K, which removes selectively the conserved glycine- and methionine-rich C terminus, leaving the chaperonin oligomer intact, prevented chaperonin association with lipid membranes. GroEL increased the lipid order in the liquid crystalline state, yet remained functional as a protein-folding chaperonin. This suggests that, during stress, chaperonins can assume the functions of assisting the folding of both soluble and membrane-associated proteins while concomitantly stabilizing lipid membranes.
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Affiliation(s)
- Z Török
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
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11
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Gorovits BM, Horowitz PM. Conditions of forming protein complexes with GroEL can influence the mechanism of chaperonin-assisted refolding. J Biol Chem 1997; 272:32-5. [PMID: 8995221 DOI: 10.1074/jbc.272.1.32] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The interaction of GroEL with urea-unfolded dihydrofolate reductase (DHFR) has been studied in the presence of DHFR substrates by investigating the ability of GroES to release enzyme under conditions where a stable GroES-GroEL-DHFR ternary complex can be formed. In these circumstances, GroES could only partially discharge the DHFR if ADP was present in the solution and approximately half of the DHFR remained bound on the chaperonin. This bound DHFR could be rescued by addition of ATP and KCl into the refolding mixture. The stable ternary complex did not show any significant protection of bound DHFR against proteolysis by Proteinase K. These results are in contrast to those observed with the GroEL-DHFR complex formed by thermal inactivation of DHFR at 45 degrees C in which GroES addition leads to partial protection of bound DHFR. Thus, the method of presentation influences the properties of the bound intermediates. It is suggested that the ability of GroES to bind on the same side of the GroEL double toroid as the target protein and displace it into the central cavity depends on the way the protein-substrate is presented to the GroEL molecule. Therefore, the compact folding intermediate formed by thermal unfolding can be protected against proteolysis after GroES binds to form a ternary complex. In addition, structural changes within GroEL induced by the experimental conditions may contribute to differences in the properties of the complexes. The more open urea-unfolded DHFR binds on the surface of chaperonin and can be displaced into solution by the tighter binding GroES molecule. It is suggested that the state of the unfolded protein when it is presented to GroEL determines the detailed mechanism of its assisted refolding. It follows that individual proteins, having characteristic folding intermediates, can have different detailed mechanisms of chaperonin-assisted folding.
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Affiliation(s)
- B M Gorovits
- Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284, USA
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12
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Mendoza JA, Campo GD. Ligand-induced conformational changes of GroEL are dependent on the bound substrate polypeptide. J Biol Chem 1996; 271:16344-9. [PMID: 8663187 DOI: 10.1074/jbc.271.27.16344] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Ligand-induced conformational changes of GroEL alone and with bound rhodanese, citrate synthase, or dihydrofolate reductase were studied by limited proteolysis. Similar digestion patterns of GroEL, with or without bound substrate polypeptide, were obtained in the absence and presence of the chaperonin ligands, K+, Mg2+, or ATP. The rates of formation and degradation of the six produced proteolytic fragments were significantly different, however. Strikingly, only with Mg2+/ATP or K+/Mg2+/ATP an additional fragment of approximately 25 kDa was generated during digestion of GroEL alone or with bound rhodanese or dihydrofolate reductase, but not with bound citrate synthase. Most of the trypsin-sensitive sites in GroEL were localized in the flexible apical domain, which contains the putative polypeptide-binding region. Our data indicate that subtle structural changes in the trypsin-sensitive regions of GroEL occur as a result of the binding of the chaperonin ligands. However, these structural changes are influenced by the GroEL substrate polypeptides.
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Affiliation(s)
- J A Mendoza
- Department of Chemistry, California State University, San Marcos, California 92096-0001, USA
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13
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Török Z, Vigh L, Goloubinoff P. Fluorescence detection of symmetric GroEL14(GroES7)2 heterooligomers involved in protein release during the chaperonin cycle. J Biol Chem 1996; 271:16180-6. [PMID: 8663256 DOI: 10.1074/jbc.271.27.16180] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The GroEL14 chaperonin from Escherichia coli was labeled with 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid (I-AEDANS), a hydrophobic probe whose fluorescent emission is sensitive to structural changes within the protein. Increasing concentrations of ATP or adenylyl imidodiphosphate but not ADP caused two successive GroES7-dependent changes in the fluorescence intensity of AEDANS-GroEL14, corresponding to the sequential binding of two GroES7 heptamers and the formation of two types of chaperonin heterooligomers, GroEL14GroES7 and GroEL14(GroES7)2. The binding of thermally denatured malate dehydrogenase (MDH) caused a specific increase in fluorescence intensity of AEDANS-GroEL14 that allowed the direct measurement in solution at equilibrium of ATP- and GroES7-dependent protein release from the chaperonin. Structure/function analysis during the generation of ATP from ADP indicated the following sequence of events: 1) ADP-stabilized MDH-GroEL14GroES7 particles bind newly formed ATP. 2) MDH-GroEL14GroES7 particles bind a second GroES7. 3) MDH-GroEL14(GroES7)2 particles productively release MDH. 4) Released MDH completes folding. Therefore, the symmetrical GroEL14(GroES7)2 heterooligomer is an intermediate after the formation of which the protein substrate is productively released during the chaperonin-mediated protein folding cycle.
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Affiliation(s)
- Z Török
- Institute of Biochemistry, Biological Research Center, Szeged, P.O. Box 521, Hungary 6701
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14
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Guthapfel R, Guéguen P, Quéméneur E. ATP binding and hydrolysis by the multifunctional protein disulfide isomerase. J Biol Chem 1996; 271:2663-6. [PMID: 8576238 DOI: 10.1074/jbc.271.5.2663] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We previously reported the ability of protein disulfide isomerase (PDI) to undergo an ATP-dependent autophosphorylation. Our efforts to map the modification site have been hindered by the low abundance and instability of the labeling. Results are presented in this paper on the nature of phospho-PDI, which appears as an intermediate with a half-life of 2.5-8.8 min in an ATPase reaction. ATP binds to PDI with high affinity, Kd 9.66 microM, and the kinetic parameters KmATP and kcat of the ATPase reaction were measured by using a pyruvate kinase-lactate dehydrogenase-coupled assay under various conditions. Strikingly, the ATPase reaction is stimulated in the presence of denatured polypeptides, while the disulfide oxidization activity of PDI is not affected by ATP. However, PDI is known to participate in various unrelated functions in the endoplasmic reticulum, and ATP could be involved in the regulation of one of these. The results are discussed in light of recent findings on ATP-chaperone relationships.
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Affiliation(s)
- R Guthapfel
- Département d'Ingéniérie et d'Etudes des Protéines, Centre d'Etudes Saclay, Gif-sur-Yvette, France
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15
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Boisvert DC, Wang J, Otwinowski Z, Horwich AL, Sigler PB. The 2.4 A crystal structure of the bacterial chaperonin GroEL complexed with ATP gamma S. NATURE STRUCTURAL BIOLOGY 1996; 3:170-7. [PMID: 8564544 DOI: 10.1038/nsb0296-170] [Citation(s) in RCA: 206] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
GroEL is a bacterial chaperonin of 14 identical subunits required to help fold newly synthesized proteins. The crystal structure of GroEL with ATP gamma S bound to each subunit shows that ATP binds to a novel pocket, whose primary sequence is highly conserved among chaperonins. Interaction of Mg2+ and ATP involves phosphate oxygens of the alpha-, beta- and gamma-phosphates, which is unique for known structures of nucleotide-binding proteins. Although bound ATP induces modest conformational shifts in the equatorial domain, the stereochemistry that functionally coordinates GroEL's affinity for nucleotides, polypeptide, and GroES remains uncertain.
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Affiliation(s)
- D C Boisvert
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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16
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Abstract
Alpha-crystallin, a multimeric protein present in the eye lens, is known to have chaperone-like activity in preventing the aggregation of enzymes and other crystallins. We have studied the chaperone-like activity of this protein towards the aggregation of insulin B chain, induced by reducing the interchain disulphide bond with dithiothreitol. At room temperature, there is no detectable protection (at a 1:1 (w/w) ratio of insulin: alpha-crystallin) against the aggregation of insulin B chain by alpha-crystallin, whereas it completely prevents this aggregation at 40 degrees C. We have monitored the temperature dependence of the protection of aggregation by alpha-crystallin; the protection increases sharply above 30 degrees C and reaches almost 100% by 41 degrees C. Probing the hydrophobic surfaces of alpha-crystallin with the hydrophobic fluorphore 8-anilino-1 naphthalene sulfonate suggests that the hydrophobic surfaces of alpha-crystallin are exposed to a greater extent above 30 degrees C. A complete prevention of the aggregation is achieved at 27.6 degrees C by increasing the concentration of alpha-crystallin by more than 8 fold. Similar temperature dependent chaperone-like activity of alpha-crystallin is observed towards the aggregation of zeta-crystallin, an enzyme crystallin from guinea pig. We have earlier shown that alpha-crystallin exposes hydrophobic surface(s) at temperatures above 30 degrees C. These results support our earlier hypothesis [Raman, B. and Rao, Ch.M. (1994) J. Biol. Chem. 269, 27264-27268] that the chaperone-like activity of alpha-crystallin is more pronounced in its structurally perturbed state.
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Affiliation(s)
- B Raman
- Centre for Cellular and Molecular Biology, Hyderabad, India
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Gibbons DL, Horowitz PM. Exposure of hydrophobic surfaces on the chaperonin GroEL oligomer by protonation or modification of His-401. J Biol Chem 1995; 270:7335-40. [PMID: 7706275 DOI: 10.1074/jbc.270.13.7335] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Hydrophobic exposure on the chaperonin GroEL is increased 6-10-fold after the protein is treated with the His-reactive reagent diethyl pyrocarbonate (DEP), or the solution pH is lowered to 5.5. The induced hydrophobic surfaces have the same 1,1'-bis(4-anilino)naphthalene-5,5'-disulfonic acid (bis-ANS) binding characteristics as unperturbed GroEL: a Kd approximately equal to 3.5 microM, a maximum intensity at approximately 500 nm, and an average fluorescence lifetime of approximately 8.0 ns. The pKa for the pH-induced transition is 6.6, most likely attributable to the only histidine in GroEL, His-401, located in the intermediate domain. The modification of one histidine residue per monomer upon DEP treatment is supported by the correlation between the change in the absorbance at 242 nm for the N-carbethoxyhistidyl derivative and the increase in bis-ANS fluorescence. GroEL at pH 5.5 is tetradecameric and can capture urea-denatured rhodanese and release it as active enzyme. The GroEL-rhodanese and release it as active enzyme. The GroEL-rhodanese complex is more stable to dissociation by 2.25 M urea than the complex formed at pH 7.8. We propose that His-401 is in a conformationally sensitive region such that protonation or modification can lead to increased exposure of hydrophobic surfaces capable of binding folding intermediates.
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Affiliation(s)
- D L Gibbons
- Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284-7760, USA
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Abstract
A comparative study has investigated the in vitro dissociation and self-assembly of chaperonin 60 14-mers isolated from E. coli (GroEL), yeast mitochondria and pea chloroplasts. In all cases Mg2+ inhibits, and low temperature stimulates, the urea-induced dissociation. ATP or ADP in the presence of Mg2+ enhance the dissociation of the chaperonins. Re-assembly of the 14-mers from their monomers shows different efficiencies between the three proteins. In all cases, however, self-assembly is stimulated by Mg-adenine nucleotides. Surprisingly, effective self-assembly of GroEL is promoted by 20% glycerol in the absence of ATP. The role of Mg-adenine nucleotides in the dissociation and assembly of the chaperonins is discussed.
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Affiliation(s)
- N M Lissin
- Centre de Biochimie et Biologie Moléculaire, Centre National de la Recherche Scientifique, Marseille, France
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Mattingly JR, Iriarte A, Martinez-Carrion M. Homologous proteins with different affinities for groEL. The refolding of the aspartate aminotransferase isozymes at varying temperatures. J Biol Chem 1995; 270:1138-48. [PMID: 7836372 DOI: 10.1074/jbc.270.3.1138] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The homologous cytosolic and mitochondrial isozymes of aspartate aminotransferase (c- and mAspAT, respectively) seem to follow very different folding pathways after synthesis in rabbit reticulocyte lysate, suggesting that the nascent proteins interact differently with molecular chaperones (Mattingly, J. R., Jr., Iriarte, A., and Martinez-Carrion, M. (1993) J. Biol. Chem. 268, 26320-26327). In an attempt to discern the structural basis for this phenomenon, we have begun to study the effect of temperature on the refolding of the guanidine hydrochloride-denatured, purified proteins and their interaction with the groEL/groES molecular chaperone system from Escherichia coli. In the absence of chaperones, temperature has a critical effect on the refolding of the two isozymes, with mAspAT being more susceptible than cAspAT to diminishing refolding yields at increasing temperatures. No refolding is observed for mAspAT at physiological temperatures. The molecular chaperones groEL and groES can extend the temperature range over which the AspAT isozymes successfully refold; however, cAspAT can still refold at higher temperatures than mAspAT. In the absence of groES and MgATP, the two isozymes interact differently with groEL, groEL arrests the refolding of mAspAT throughout the temperature range of 0-45 degrees C. Adding only MgATP releases very little mAspAT from groEL; both groES and MgATP are required for significant refolding of mAspAT in the presence of groEL. On the other hand, the extent to which groEL inhibits the refolding of cAspAT depends upon the temperature of the refolding reaction, only slowing the reaction at 0 degrees C but arresting it completely at 30 degrees C. MgATP alone is sufficient to effect the release of cAspAT from groEL at any temperature examined; inclusion of groES along with MgATP has no effect on the refolding yield but does increase the refolding rate at temperatures greater than 15 degrees C. These results demonstrate that groEL can have significantly different affinities for proteins with highly homologous final tertiary and quarternary structures and suggest that dissimilarities in the primary sequence of the protein substrates may control the structure of the folding intermediates captured by groEL and/or the composition of the surfaces through which the folding proteins interact with groEL.
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Affiliation(s)
- J R Mattingly
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri, Kansas City 64110-2499
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Muller AW. Were the first organisms heat engines? A new model for biogenesis and the early evolution of biological energy conversion. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1995; 63:193-231. [PMID: 7542789 DOI: 10.1016/0079-6107(95)00004-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- A W Muller
- E.C. Slater Institute, BioCentrum Amsterdam, Universiteit van Amsterdam, The Netherlands
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22
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McLennan NF, McAteer S, Masters M. The tail of a chaperonin: the C-terminal region of Escherichia coli GroEL protein. Mol Microbiol 1994; 14:309-21. [PMID: 7830575 DOI: 10.1111/j.1365-2958.1994.tb01292.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The active form of the HSP60 molecular chaperone of Escherichia coli, GroEL, is a pair of seven-membered rings. We have used site-directed mutagenesis to construct forms of the 547-amino-acid monomer truncated at the C-terminus. We show here that forms that are 520 amino acids long or longer are close to being fully functional. Removing one further amino acid, however, results in a protein, GroEL519, which retains little function. This truncated form is metabolically stable but is not recovered from the cell in particle form. When synthesized at high levels, it prevents the normal assembly of GroEL547 present in the same cell. When synthesized at low levels, it can be included, probably at low molar ratios, in particles formed by assembly-competent forms of GroEL. This can be seen as partial complementation of the temperature-sensitive mutant groEL44. We conclude that amino acid 520 is crucial for particle assembly. GroEL516 has in vivo properties similar to those of GroEL516 has in vivo properties similar to those of GroEL519, but the still shorter form, GroEL504, appears to be inactive.
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Affiliation(s)
- N F McLennan
- Institute of Cell and Molecular Biology, University of Edinburgh, UK
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