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Ooka K, Liu R, Arai M. The Wako-Saitô-Muñoz-Eaton Model for Predicting Protein Folding and Dynamics. Molecules 2022; 27:molecules27144460. [PMID: 35889332 PMCID: PMC9319528 DOI: 10.3390/molecules27144460] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022] Open
Abstract
Despite the recent advances in the prediction of protein structures by deep neutral networks, the elucidation of protein-folding mechanisms remains challenging. A promising theory for describing protein folding is a coarse-grained statistical mechanical model called the Wako-Saitô-Muñoz-Eaton (WSME) model. The model can calculate the free-energy landscapes of proteins based on a three-dimensional structure with low computational complexity, thereby providing a comprehensive understanding of the folding pathways and the structure and stability of the intermediates and transition states involved in the folding reaction. In this review, we summarize previous and recent studies on protein folding and dynamics performed using the WSME model and discuss future challenges and prospects. The WSME model successfully predicted the folding mechanisms of small single-domain proteins and the effects of amino-acid substitutions on protein stability and folding in a manner that was consistent with experimental results. Furthermore, extended versions of the WSME model were applied to predict the folding mechanisms of multi-domain proteins and the conformational changes associated with protein function. Thus, the WSME model may contribute significantly to solving the protein-folding problem and is expected to be useful for predicting protein folding, stability, and dynamics in basic research and in industrial and medical applications.
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Affiliation(s)
- Koji Ooka
- Department of Physics, Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan;
- Komaba Organization for Educational Excellence, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
| | - Runjing Liu
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan;
| | - Munehito Arai
- Department of Physics, Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan;
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan;
- Correspondence:
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Kuwajima K, Yagi-Utsumi M, Yanaka S, Kato K. DMSO-Quenched H/D-Exchange 2D NMR Spectroscopy and Its Applications in Protein Science. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123748. [PMID: 35744871 PMCID: PMC9230524 DOI: 10.3390/molecules27123748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022]
Abstract
Hydrogen/deuterium (H/D) exchange combined with two-dimensional (2D) NMR spectroscopy has been widely used for studying the structure, stability, and dynamics of proteins. When we apply the H/D-exchange method to investigate non-native states of proteins such as equilibrium and kinetic folding intermediates, H/D-exchange quenching techniques are indispensable, because the exchange reaction is usually too fast to follow by 2D NMR. In this article, we will describe the dimethylsulfoxide (DMSO)-quenched H/D-exchange method and its applications in protein science. In this method, the H/D-exchange buffer is replaced by an aprotic DMSO solution, which quenches the exchange reaction. We have improved the DMSO-quenched method by using spin desalting columns, which are used for medium exchange from the H/D-exchange buffer to the DMSO solution. This improvement has allowed us to monitor the H/D exchange of proteins at a high concentration of salts or denaturants. We describe methodological details of the improved DMSO-quenched method and present a case study using the improved method on the H/D-exchange behavior of unfolded human ubiquitin in 6 M guanidinium chloride.
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Affiliation(s)
- Kunihiro Kuwajima
- Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Correspondence: (K.K.); (K.K.)
| | - Maho Yagi-Utsumi
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
| | - Saeko Yanaka
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
- Correspondence: (K.K.); (K.K.)
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Sivaraman T, Richa T. Cryptic intermediates and metastable states of proteins as predicted by OneG computational method. J Biomol Struct Dyn 2021; 40:7899-7914. [PMID: 33764262 DOI: 10.1080/07391102.2021.1904288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Understanding structural excursions of proteins under folding conditions is crucial to map energy landscapes of proteins. In the present study, OneG computational tool has been used for analyzing possible existence of cryptic intermediates and metastable states of 26 proteins for which three prerequisite inputs of the OneG such as atomic coordinates of proteins, free energy of unfolding (ΔGU) and free energy of exchange (ΔGHX) determined in the absence of denaturant were available during the course of the study. The veraciousness of the tool on predicting the partially folded states of the proteins has been comprehensively described using experimental data available for 15 of the 26 proteins. Meanwhile, possible existence of partially structured states in the folding pathways of 11 other proteins has also been delineated as predicted by the OneG. In addition to mapping the folding pathways of proteins, the salient merits of the tool on systematically addressing the discrepancy between the ΔGU and the ΔGHX of the proteins have also been dealt.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Thirunavukkarasu Sivaraman
- Drug Design and Discovery Lab, Department of Biotechnology, Karpagam Academy of Higher Education (Deemed to be University), Coimbatore, Tamil Nadu, India
| | - Tambi Richa
- Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, UAE
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α-Lactalbumin, Amazing Calcium-Binding Protein. Biomolecules 2020; 10:biom10091210. [PMID: 32825311 PMCID: PMC7565966 DOI: 10.3390/biom10091210] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4–5), Ca2+-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the lactating mammary gland. The protein possesses a single strong Ca2+-binding site, which can also bind Mg2+, Mn2+, Na+, K+, and some other metal cations. It contains several distinct Zn2+-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions, α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca2+, increases stability of α-LA against the action of heat, various denaturing agents and proteases, while the binding of Zn2+ to the Ca2+-loaded protein decreases its stability and causes its aggregation. At pH 2, the protein is in the classical molten globule state. α-LA can associate with membranes at neutral or slightly acidic pH at physiological temperatures. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. Some of these aggregated states of α-LA can be used in practical applications such as drug delivery to tissues and organs. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid are cytotoxic to various tumor and bacterial cells. α-LA in the cytotoxic complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor and bacterial cells across the cell membrane. Perhaps in the future the complexes of α-LA with oleic acid will be used for development of new anti-cancer drugs.
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Shimizu M, Kajikawa Y, Kuwajima K, Dobson CM, Okamoto Y. Determination of the structural ensemble of the molten globule state of a protein by computer simulations. Proteins 2019; 87:635-645. [PMID: 30958596 DOI: 10.1002/prot.25688] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/20/2019] [Accepted: 04/04/2019] [Indexed: 11/08/2022]
Abstract
We have used computer simulations to investigate the structural nature of the molten globule (MG) state of canine milk lysozyme. To sample the conformational space efficiently, we performed replica-exchange umbrella sampling simulations with the radius of gyration as a reaction coordinate. We applied the Weighted Histogram Analysis Method to the trajectory of the simulations to obtain the potential of mean force, from which we identified representative structures corresponding to local minima in the free energy surface. The representative structures obtained in this way are in accord with the characteristics of the MG state reported previously by experimental studies. We conjecture that the MG state comprises a series of partially structured states undergoing relatively fast conformational interchange.
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Affiliation(s)
- Masahiro Shimizu
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
| | - Yukihito Kajikawa
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
| | - Kunihiro Kuwajima
- Department of Physics, Graduate School of Science, University of Tokyo, Tokyo, Japan.,School of Computational Sciences, Korea Institute for Advanced Study (KIAS), Seoul, Korea
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Yuko Okamoto
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan.,Information Technology Center, Nagoya University, Nagoya, Aichi, Japan.,Structural Biology Research Center, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan.,Center for Computational Science, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, Japan.,JST-CREST, Nagoya, Aichi, Japan
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Romero-Romero S, Becerril-Sesín LA, Costas M, Rodríguez-Romero A, Fernández-Velasco DA. Structure and conformational stability of the triosephosphate isomerase from Zea mays. Comparison with the chemical unfolding pathways of other eukaryotic TIMs. Arch Biochem Biophys 2018; 658:66-76. [PMID: 30261166 DOI: 10.1016/j.abb.2018.09.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/18/2018] [Accepted: 09/23/2018] [Indexed: 12/16/2022]
Abstract
We studied the structure, function and thermodynamic properties for the unfolding of the Triosephosphate isomerase (TIM) from Zea mays (ZmTIM). ZmTIM shows a catalytic efficiency close to the diffusion limit. Native ZmTIM is a dimer that dissociates upon dilution into inactive and unfolded monomers. Its thermal unfolding is irreversible with a Tm of 61.6 ± 1.4 °C and an activation energy of 383.4 ± 11.5 kJ mol-1. The urea-induced unfolding of ZmTIM is reversible. Transitions followed by catalytic activity and spectroscopic properties are monophasic and superimposable, indicating that ZmTIM unfolds/refolds in a two-state behavior with an unfolding ΔG°(H20) = 99.8 ± 5.3 kJ mol-1. This contrasts with most other studied TIMs, where folding intermediates are common. The three-dimensional structure of ZmTIM was solved at 1.8 Å. A structural comparison with other eukaryotic TIMs shows a similar number of intramolecular and intermolecular interactions. Interestingly the number of interfacial water molecules found in ZmTIM is lower than those observed in most TIMs that show folding intermediates. Although with the available data, there is no clear correlation between structural properties and the number of equilibrium intermediates in the unfolding of TIM, the identification of such structural properties should increase our understanding of folding mechanisms.
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Affiliation(s)
- Sergio Romero-Romero
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico
| | - Luis A Becerril-Sesín
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico
| | - Miguel Costas
- Laboratorio de Biofisicoquímica, Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico
| | - Adela Rodríguez-Romero
- Laboratorio de Química de Biomacromoléculas 3, Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico
| | - D Alejandro Fernández-Velasco
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico.
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Makabe K, Nakamura T, Dhar D, Ikura T, Koide S, Kuwajima K. An Overlapping Region between the Two Terminal Folding Units of the Outer Surface Protein A (OspA) Controls Its Folding Behavior. J Mol Biol 2018; 430:1799-1813. [PMID: 29709572 DOI: 10.1016/j.jmb.2018.04.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/12/2018] [Accepted: 04/18/2018] [Indexed: 10/17/2022]
Abstract
Although many naturally occurring proteins consist of multiple domains, most studies on protein folding to date deal with single-domain proteins or isolated domains of multi-domain proteins. Studies of multi-domain protein folding are required for further advancing our understanding of protein folding mechanisms. Borrelia outer surface protein A (OspA) is a β-rich two-domain protein, in which two globular domains are connected by a rigid and stable single-layer β-sheet. Thus, OspA is particularly suited as a model system for studying the interplays of domains in protein folding. Here, we studied the equilibria and kinetics of the urea-induced folding-unfolding reactions of OspA probed with tryptophan fluorescence and ultraviolet circular dichroism. Global analysis of the experimental data revealed compelling lines of evidence for accumulation of an on-pathway intermediate during kinetic refolding and for the identity between the kinetic intermediate and a previously described equilibrium unfolding intermediate. The results suggest that the intermediate has the fully native structure in the N-terminal domain and the single layer β-sheet, with the C-terminal domain still unfolded. The observation of the productive on-pathway folding intermediate clearly indicates substantial interactions between the two domains mediated by the single-layer β-sheet. We propose that a rigid and stable intervening region between two domains creates an overlap between two folding units and can energetically couple their folding reactions.
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Affiliation(s)
- Koki Makabe
- Graduate School of Science and Engineering, Yamagata University, Jyonan 4-3-16, Yonezawa, Yamagata 992-8510, Japan; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
| | - Takashi Nakamura
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Debanjan Dhar
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Teikichi Ikura
- Laboratory of Structural Biology, School of Biomedical Science, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Shohei Koide
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, and Perlmutter Cancer Center at NYU Langone Health, New York, NY 10016, USA
| | - Kunihiro Kuwajima
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Physics, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; School of Computational Sciences, Korea Institute for Advanced Study (KIAS), Dongdaemun-gu, Seoul 130-722, Korea
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Arai M. Unified understanding of folding and binding mechanisms of globular and intrinsically disordered proteins. Biophys Rev 2018; 10:163-181. [PMID: 29307002 PMCID: PMC5899706 DOI: 10.1007/s12551-017-0346-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022] Open
Abstract
Extensive experimental and theoretical studies have advanced our understanding of the mechanisms of folding and binding of globular proteins, and coupled folding and binding of intrinsically disordered proteins (IDPs). The forces responsible for conformational changes and binding are common in both proteins; however, these mechanisms have been separately discussed. Here, we attempt to integrate the mechanisms of coupled folding and binding of IDPs, folding of small and multi-subdomain proteins, folding of multimeric proteins, and ligand binding of globular proteins in terms of conformational selection and induced-fit mechanisms as well as the nucleation–condensation mechanism that is intermediate between them. Accumulating evidence has shown that both the rate of conformational change and apparent rate of binding between interacting elements can determine reaction mechanisms. Coupled folding and binding of IDPs occurs mainly by induced-fit because of the slow folding in the free form, while ligand binding of globular proteins occurs mainly by conformational selection because of rapid conformational change. Protein folding can be regarded as the binding of intramolecular segments accompanied by secondary structure formation. Multi-subdomain proteins fold mainly by the induced-fit (hydrophobic collapse) mechanism, as the connection of interacting segments enhances the binding (compaction) rate. Fewer hydrophobic residues in small proteins reduce the intramolecular binding rate, resulting in the nucleation–condensation mechanism. Thus, the folding and binding of globular proteins and IDPs obey the same general principle, suggesting that the coarse-grained, statistical mechanical model of protein folding is promising for a unified theoretical description of all mechanisms.
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Affiliation(s)
- Munehito Arai
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
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Ge B, Jiang X, Chen Y, Sun T, Yang Q, Huang F. Kinetic and thermodynamic studies reveal chemokine homologues CC11 and CC24 with an almost identical tertiary structure have different folding pathways. BMC BIOPHYSICS 2017; 10:7. [PMID: 28919974 PMCID: PMC5596964 DOI: 10.1186/s13628-017-0039-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/06/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND Proteins with low sequence identity but almost identical tertiary structure and function have been valuable to uncover the relationship between sequence, tertiary structure, folding mechanism and functions. Two homologous chemokines, CCL11 and CCL24, with low sequence identity but similar tertiary structure and function, provide an excellent model system for respective studies. RESULTS The kinetics and thermodynamics of the two homologous chemokines were systematically characterized. Despite their similar tertiary structures, CCL11 and CCL24 show different thermodynamic stability in guanidine hydrochloride titration, with D50% = 2.20 M and 4.96 M, respectively. The kinetics curves clearly show two phases in the folding/unfolding processes of both CCL11 and CCL24, which suggests the existence of an intermediate state in their folding/unfolding processes. The folding pathway of both CCL11 and CCL24 could be well described using a folding model with an on-pathway folding intermediate. However, the folding kinetics and stability of the intermediate state of CCL11 and CCL24 are obviously different. CONCLUSION Our results suggest homologous proteins with low sequence identity can display almost identical tertiary structure, but very different folding mechanisms, which applies to homologues in the chemokine protein family, extending the general applicability of the above observation.
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Affiliation(s)
- Baosheng Ge
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
| | - Xiaoyong Jiang
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
| | - Yao Chen
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
| | - Tingting Sun
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
| | - Qiuxia Yang
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
| | - Fang Huang
- Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580 People's Republic of China
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Shinozaki R, Iwaoka M. Effects of Metal Ions, Temperature, and a Denaturant on the Oxidative Folding Pathways of Bovine α-Lactalbumin. Int J Mol Sci 2017; 18:ijms18091996. [PMID: 28926961 PMCID: PMC5618645 DOI: 10.3390/ijms18091996] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 12/02/2022] Open
Abstract
Bovine α-lactalbumin (αLA) has four disulfide (SS) bonds in the native form (N). On the oxidative folding pathways of this protein, two specific SS folding intermediates, i.e., (61–77, 73–91) and des[6–120], which have two and three native SS bonds, respectively, accumulate predominantly in the presence of Ca2+. In this study, we reinvestigated the pathways using a water-soluble cyclic selenoxide reagent, trans-3,4-dihydroxyselenolane oxide (DHSox), as a strong and quantitative oxidant to oxidize the fully reduced form (R). In the presence of ethylenediaminetetraacetic acid (EDTA) (under a metal-free condition), SS formation randomly proceeded, and N did not regenerate. On the other hand, two specific SS intermediates transiently generated in the presence of Ca2+. These intermediates could be assigned to (61–77, 73–91) and des[6–120] having two common SS bonds, i.e., Cys61-Cys77 and Cys73-Cys91, near the calcium binding pocket of the β-sheet domain. Much faster folding to N was observed in the presence of Mn2+, whereas Na+, K+, Mg2+, and Zn2+ did not affect the pathways. The two key intermediates were susceptible to temperature and a denaturant. The oxidative folding pathways revealed were significantly different from those of hen egg white lysozyme, which has the same SS-bonding pattern as αLA, suggesting that the folding pathways of SS-containing proteins can alter depending on the amino acid sequence and other factors, even when the SS-bond topologies are similar to each other.
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Affiliation(s)
- Reina Shinozaki
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Michio Iwaoka
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
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Nishio M. Myths in Modern Science: The Hydrogen Bond and its Surroundings. Part 1. The Hydrogen-Bond-Myth. CHEM-BIO INFORMATICS JOURNAL 2017. [DOI: 10.1273/cbij.17.85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Sacquin-Mora S. Fold and flexibility: what can proteins' mechanical properties tell us about their folding nucleus? J R Soc Interface 2016; 12:rsif.2015.0876. [PMID: 26577596 DOI: 10.1098/rsif.2015.0876] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The determination of a protein's folding nucleus, i.e. a set of native contacts playing an important role during its folding process, remains an elusive yet essential problem in biochemistry. In this work, we investigate the mechanical properties of 70 protein structures belonging to 14 protein families presenting various folds using coarse-grain Brownian dynamics simulations. The resulting rigidity profiles combined with multiple sequence alignments show that a limited set of rigid residues, which we call the consensus nucleus, occupy conserved positions along the protein sequence. These residues' side chains form a tight interaction network within the protein's core, thus making our consensus nuclei potential folding nuclei. A review of experimental and theoretical literature shows that most (above 80%) of these residues were indeed identified as folding nucleus member in earlier studies.
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Affiliation(s)
- Sophie Sacquin-Mora
- Laboratoire de Biochimie Théorique, CNRS UPR9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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Matsuoka M, Kikuchi T. Sequence analysis on the information of folding initiation segments in ferredoxin-like fold proteins. BMC STRUCTURAL BIOLOGY 2014; 14:15. [PMID: 24884463 PMCID: PMC4055915 DOI: 10.1186/1472-6807-14-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 05/15/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND While some studies have shown that the 3D protein structures are more conservative than their amino acid sequences, other experimental studies have shown that even if two proteins share the same topology, they may have different folding pathways. There are many studies investigating this issue with molecular dynamics or Go-like model simulations, however, one should be able to obtain the same information by analyzing the proteins' amino acid sequences, if the sequences contain all the information about the 3D structures. In this study, we use information about protein sequences to predict the location of their folding segments. We focus on proteins with a ferredoxin-like fold, which has a characteristic topology. Some of these proteins have different folding segments. RESULTS Despite the simplicity of our methods, we are able to correctly determine the experimentally identified folding segments by predicting the location of the compact regions considered to play an important role in structural formation. We also apply our sequence analyses to some homologues of each protein and confirm that there are highly conserved folding segments despite the homologues' sequence diversity. These homologues have similar folding segments even though the homology of two proteins' sequences is not so high. CONCLUSION Our analyses have proven useful for investigating the common or different folding features of the proteins studied.
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Affiliation(s)
| | - Takeshi Kikuchi
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan.
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Nakamura T, Aizawa T, Kariya R, Okada S, Demura M, Kawano K, Makabe K, Kuwajima K. Molecular mechanisms of the cytotoxicity of human α-lactalbumin made lethal to tumor cells (HAMLET) and other protein-oleic acid complexes. J Biol Chem 2013; 288:14408-14416. [PMID: 23580643 DOI: 10.1074/jbc.m112.437889] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Although HAMLET (human α-lactalbumin made lethal to tumor cells), a complex formed by human α-lactalbumin and oleic acid, has a unique apoptotic activity for the selective killing of tumor cells, the molecular mechanisms of expression of the HAMLET activity are not well understood. Therefore, we studied the molecular properties of HAMLET and its goat counterpart, GAMLET (goat α-lactalbumin made lethal to tumor cells), by pulse field gradient NMR and 920-MHz two-dimensional NMR techniques. We also examined the expression of HAMLET-like activities of complexes between oleic acid and other proteins that form a stable molten globule state. We observed that both HAMLET and GAMLET at pH 7.5 were heterogeneous, composed of the native protein, the monomeric molten globule-like state, and the oligomeric species. At pH 2.0 and 50 °C, HAMLET and GAMLET appeared in the monomeric state, and we identified the oleic acid-binding site in the complexes by two-dimensional NMR. Rather surprisingly, the binding site thus identified was markedly different between HAMLET and GAMLET. Furthermore, canine milk lysozyme, apo-myoglobin, and β2-microglobulin all formed the HAMLET-like complex with the anti-tumor activity, when the protein was treated with oleic acid under conditions in which their molten globule states were stable. From these results, we conclude that the protein portion of HAMLET, GAMLET, and the other HAMLET-like protein-oleic acid complexes is not the origin of their cytotoxicity to tumor cells and that the protein portion of these complexes plays a role in the delivery of cytotoxic oleic acid molecules into tumor cells across the cell membrane.
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Affiliation(s)
- Takashi Nakamura
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Ryusho Kariya
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Seiji Okada
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Keiichi Kawano
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Koki Makabe
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Kunihiro Kuwajima
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
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15
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Aghera N, Udgaonkar JB. Kinetic Studies of the Folding of Heterodimeric Monellin: Evidence for Switching between Alternative Parallel Pathways. J Mol Biol 2012; 420:235-50. [DOI: 10.1016/j.jmb.2012.04.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 04/14/2012] [Accepted: 04/18/2012] [Indexed: 11/17/2022]
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16
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Tomoyori K, Nakamura T, Makabe K, Maki K, Saeki K, Kuwajima K. Sequential four-state folding/unfolding of goat α-lactalbumin and its N-terminal variants. Proteins 2012; 80:2191-206. [PMID: 22577070 DOI: 10.1002/prot.24109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/11/2012] [Accepted: 04/25/2012] [Indexed: 11/09/2022]
Abstract
Equilibria and kinetics of folding/unfolding of α-lactalbumin and its two N-terminal variants were studied by circular dichroism spectroscopy. The two variants were wild-type recombinant and Glu1-deletion (E1M) variants expressed in Escherichia coli. The presence of an extra methionine at the N terminus in recombinant α-lactalbumin destabilized the protein by 2 kcal/mol, while the stability was recovered in the E1M variant in which Glu1 was replaced by Met1. Kinetic folding/unfolding reactions of the proteins, induced by stopped-flow concentration jumps of guanidine hydrochloride, indicated the presence of a burst-phase in refolding, and gave chevron plots with significant curvatures in both the folding and unfolding limbs. The folding-limb curvature was interpreted in terms of accumulation of the burst-phase intermediate. However, there was no burst phase observed in the unfolding kinetics to interpret the unfolding-limb curvature. We thus assumed a sequential four-state mechanism, in which the folding from the burst-phase intermediate takes place via two transition states separated by a high-energy intermediate. We estimated changes in the free energies of the burst-phase intermediate and two transition states, caused by the N-terminal variations and also by the presence of stabilizing calcium ions. The Φ values at the N terminus and at the Ca(2+)-binding site thus obtained increased successively during folding, demonstrating the validity of the sequential mechanism. The stability and the folding behavior of the E1M variant were essentially identical to those of the authentic protein, allowing us to use this variant as a pseudo-wild-type α-lactalbumin in future studies.
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Affiliation(s)
- Katsuaki Tomoyori
- Department of Physics, School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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17
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Katopo L, Kasapis S, Hemar Y. Segregative phase separation in agarose/whey protein systems induced by sequence-dependent trapping and change in pH. Carbohydr Polym 2012. [DOI: 10.1016/j.carbpol.2011.10.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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18
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The evolution of protein structures and structural ensembles under functional constraint. Genes (Basel) 2011; 2:748-62. [PMID: 24710290 PMCID: PMC3927589 DOI: 10.3390/genes2040748] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Revised: 10/15/2011] [Accepted: 10/19/2011] [Indexed: 02/06/2023] Open
Abstract
Protein sequence, structure, and function are inherently linked through evolution and population genetics. Our knowledge of protein structure comes from solved structures in the Protein Data Bank (PDB), our knowledge of sequence through sequences found in the NCBI sequence databases (http://www.ncbi.nlm.nih.gov/), and our knowledge of function through a limited set of in-vitro biochemical studies. How these intersect through evolution is described in the first part of the review. In the second part, our understanding of a series of questions is addressed. This includes how sequences evolve within structures, how evolutionary processes enable structural transitions, how the folding process can change through evolution and what the fitness impacts of this might be. Moving beyond static structures, the evolution of protein kinetics (including normal modes) is discussed, as is the evolution of conformational ensembles and structurally disordered proteins. This ties back to a question of the role of neostructuralization and how it relates to selection on sequences for functions. The relationship between metastability, the fitness landscape, sequence divergence, and organismal effective population size is explored. Lastly, a brief discussion of modeling the evolution of sequences of ordered and disordered proteins is entertained.
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Chen J, Makabe K, Nakamura T, Inobe T, Kuwajima K. Dissecting a bimolecular process of MgATP²- binding to the chaperonin GroEL. J Mol Biol 2011; 410:343-56. [PMID: 21620859 DOI: 10.1016/j.jmb.2011.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/17/2011] [Accepted: 05/11/2011] [Indexed: 11/29/2022]
Abstract
Although allosteric transitions of GroEL by MgATP(2)(-) have been widely studied, the initial bimolecular step of MgATP(2-) binding to GroEL remains unclear. Here, we studied the equilibrium and kinetics of MgATP(2)(-) binding to a variant of GroEL, in which Tyr485 was replaced by tryptophan, via isothermal titration calorimetry (ITC) and stopped-flow fluorescence spectroscopy. In the absence of K(+) at 4-5 °C, the allosteric transitions and the subsequent ATP hydrolysis by GroEL are halted, and hence, the stopped-flow fluorescence kinetics induced by rapid mixing of MgATP(2)(-) and the GroEL variant solely reflected MgATP(2)(-) binding, which was well represented by bimolecular noncooperative binding with a binding rate constant, k(on), of 9.14×10(4) M(-1) s(-1) and a dissociation rate constant, k(off), of 14.2 s(-1), yielding a binding constant, K(b) (=k(on)/k(off)), of 6.4×10(3) M(-1). We also successfully performed ITC to measure binding isotherms of MgATP(2)(-) to GroEL and obtained a K(b) of 9.5×10(3) M(-1) and a binding stoichiometric number of 6.6. K(b) was thus in good agreement with that obtained by stopped-flow fluorescence. In the presence of 10-50 mM KCl, the fluorescence kinetics consisted of three to four phases (the first fluorescence-increasing phase, followed by one or two exponential fluorescence-decreasing phases, and the final slow fluorescence-increasing phase), and comparison of the kinetics in the absence and presence of K(+) clearly demonstrated that the first fluorescence-increasing phase corresponds to bimolecular MgATP(2)(-) binding to GroEL. The temperature dependence of the kinetics indicated that MgATP(2)(-) binding to GroEL was activation-controlled with an activation enthalpy as large as 14-16 kcal mol(-1).
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Affiliation(s)
- Jin Chen
- 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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Bhuyan AK. Off-Pathway Status for the Alkali Molten Globule of Horse Ferricytochrome c. Biochemistry 2010; 49:7764-73. [DOI: 10.1021/bi100880d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Abani K. Bhuyan
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
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What lessons can be learned from studying the folding of homologous proteins? Methods 2010; 52:38-50. [PMID: 20570731 PMCID: PMC2965948 DOI: 10.1016/j.ymeth.2010.06.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 05/25/2010] [Accepted: 06/01/2010] [Indexed: 01/30/2023] Open
Abstract
The studies of the folding of structurally related proteins have proved to be a very important tool for investigating protein folding. Here we review some of the insights that have been gained from such studies. Our highlighted studies show just how such an investigation should be designed and emphasise the importance of the synergy between experiment and theory. We also stress the importance of choosing the right system carefully, exploiting the excellent structural and sequence databases at our disposal.
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