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Zhang Z, Cai Y, Zheng N, Deng Y, Gao L, Wang Q, Xia X. Diverse models of cavity engineering in enzyme modification: Creation, filling, and reshaping. Biotechnol Adv 2024; 72:108346. [PMID: 38518963 DOI: 10.1016/j.biotechadv.2024.108346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 03/07/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
Most enzyme modification strategies focus on designing the active sites or their surrounding structures. Interestingly, a large portion of the enzymes (60%) feature active sites located within spacious cavities. Despite recent discoveries, cavity-mediated enzyme engineering remains crucial for enhancing enzyme properties and unraveling folding-unfolding mechanisms. Cavity engineering influences enzyme stability, catalytic activity, specificity, substrate recognition, and docking. This article provides a comprehensive review of various cavity engineering models for enzyme modification, including cavity creation, filling, and reshaping. Additionally, it also discusses feasible tools for geometric analysis, functional assessment, and modification of cavities, and explores potential future research directions in this field. Furthermore, a promising universal modification strategy for cavity engineering that leverages state-of-the-art technologies and methodologies to tailor cavities according to the specific requirements of industrial production conditions is proposed.
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Affiliation(s)
- Zehua Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Yongchao Cai
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Nan Zheng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Yu Deng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Ling Gao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Qiong Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China.
| | - Xiaole Xia
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China; College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, PR China.
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2
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Acharya N, Jha SK. Dry Molten Globule-Like Intermediates in Protein Folding, Function, and Disease. J Phys Chem B 2022; 126:8614-8622. [PMID: 36286394 DOI: 10.1021/acs.jpcb.2c04991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The performance of a protein depends on its correct folding to the final functional native form. Hence, understanding the process of protein folding has remained an important field of research for the scientific community for the past five decades. Two important intermediate states, namely, wet molten globule (WMG) and dry molten globule (DMG), have emerged as critical milestones during protein folding-unfolding reactions. While much has been discussed about WMGs as a common unfolding intermediate, the evidence for DMGs has remained elusive owing to their near-native features, which makes them difficult to probe using global structural probes. This Review puts together the available literature and new evidence on DMGs to give a broader perspective on the universality of DMGs and discuss their significance in protein folding, function, and disease.
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Affiliation(s)
- Nirbhik Acharya
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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3
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Balachandran N, Grainger RA, Rob T, Liuni P, Wilson DJ, Junop MS, Berti PJ. Role of Half-of-Sites Reactivity and Inter-Subunit Communications in DAHP Synthase Catalysis and Regulation. Biochemistry 2022; 61:2229-2240. [PMID: 36197914 DOI: 10.1021/acs.biochem.2c00465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
α-Carboxyketose synthases, including 3-deoxy-d-arabinoheptulosonate 7-phosphate synthase (DAHPS), are long-standing targets for inhibition. They are challenging targets to create tight-binding inhibitors against, and inhibitors often display half-of-sites binding and partial inhibition. Half-of-sites inhibition demonstrates the existence of inter-subunit communication in DAHPS. We used X-ray crystallography and spatially resolved hydrogen-deuterium exchange (HDX) to reveal the structural and dynamic bases for inter-subunit communication in Escherichia coli DAHPS(Phe), the isozyme that is feedback-inhibited by phenylalanine. Crystal structures of this homotetrameric (dimer-of-dimers) enzyme are invariant over 91% of its sequence. Three variable loops make up 8% of the sequence and are all involved in inter-subunit contacts across the tight-dimer interface. The structures have pseudo-twofold symmetry indicative of inter-subunit communication across the loose-dimer interface, with the diagonal subunits B and C always having the same conformation as each other, while subunits A and D are variable. Spatially resolved HDX reveals contrasting responses to ligand binding, which, in turn, affect binding of the second substrate, erythrose-4-phosphate (E4P). The N-terminal peptide, M1-E12, and the active site loop that binds E4P, F95-K105, are key parts of the communication network. Inter-subunit communication appears to have a catalytic role in all α-carboxyketose synthase families and a regulatory role in some members.
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Affiliation(s)
| | - Ryan A Grainger
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
| | - Tamanna Rob
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Peter Liuni
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Derek J Wilson
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
| | - Murray S Junop
- Department of Biochemistry, Molecular Biology Lab, Western University, London, Ontario N6A 5C1, Canada
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4
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Parray ZA, Shahid M, Islam A. Insights into Fluctuations of Structure of Proteins: Significance of Intermediary States in Regulating Biological Functions. Polymers (Basel) 2022; 14:polym14081539. [PMID: 35458289 PMCID: PMC9025146 DOI: 10.3390/polym14081539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023] Open
Abstract
Proteins are indispensable to cellular communication and metabolism. The structure on which cells and tissues are developed is deciphered from proteins. To perform functions, proteins fold into a three-dimensional structural design, which is specific and fundamentally determined by their characteristic sequence of amino acids. Few of them have structural versatility, allowing them to adapt their shape to the task at hand. The intermediate states appear momentarily, while protein folds from denatured (D) ⇔ native (N), which plays significant roles in cellular functions. Prolific effort needs to be taken in characterizing these intermediate species if detected during the folding process. Protein folds into its native structure through definite pathways, which involve a limited number of transitory intermediates. Intermediates may be essential in protein folding pathways and assembly in some cases, as well as misfolding and aggregation folding pathways. These intermediate states help to understand the machinery of proper folding in proteins. In this review article, we highlight the various intermediate states observed and characterized so far under in vitro conditions. Moreover, the role and significance of intermediates in regulating the biological function of cells are discussed clearly.
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Affiliation(s)
- Zahoor Ahmad Parray
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Department of Chemistry, Indian Institute of Technology Delhi, IIT Campus, Hauz Khas, New Delhi 110016, India
| | - Mohammad Shahid
- Department of Basic Medical Sciences, College of Medicine, Prince Sattam bin Abdulaziz University, Al Kharj 11942, Saudi Arabia;
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Correspondence: ; Tel.: +91-93-1281-2007
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5
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The native state conformational heterogeneity in the energy landscape of protein folding. Biophys Chem 2022; 283:106761. [DOI: 10.1016/j.bpc.2022.106761] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/18/2022]
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6
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Wu C, Wang T, Ren C, Ma W, Wu D, Xu X, Wang LS, Du M. Advancement of food-derived mixed protein systems: Interactions, aggregations, and functional properties. Compr Rev Food Sci Food Saf 2020; 20:627-651. [PMID: 33325130 DOI: 10.1111/1541-4337.12682] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/31/2020] [Accepted: 11/12/2020] [Indexed: 11/30/2022]
Abstract
Recently, interests in binary protein systems have been developed considerably ascribed to the sustainability, environment-friendly, rich in nutrition, low cost, and tunable mechanical properties of these systems. However, the molecular coalition is challenged by the complex mechanisms of interaction, aggregation, gelation, and emulsifying of the mixed system in which another protein is introduced. To overcome these fundamental difficulties and better modulate the structural and functional properties of binary systems, efforts have been steered to gain basic information regarding the underlying dynamics, theories, and physicochemical characteristics of mixed systems. Therefore, the present review provides an overview of the current studies on the behaviors of proteins in such systems and highlights shortcomings and future challenges when applied in scientific fields.
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Affiliation(s)
- Chao Wu
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Tao Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Chao Ren
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Wuchao Ma
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Di Wu
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Xianbing Xu
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
| | - Li-Shu Wang
- Division of Hematology and Oncology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ming Du
- Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, China
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7
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Disentangling the role of solvent polarity and protein solvation in folding and self-assembly of α-lactalbumin. J Colloid Interface Sci 2020; 561:749-761. [DOI: 10.1016/j.jcis.2019.11.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/29/2019] [Accepted: 11/14/2019] [Indexed: 12/31/2022]
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8
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Rodrigues RM, Claro B, Bastos M, Pereira RN, Vicente AA, Petersen SB. Multi-step thermally induced transitions of β-lactoglobulin – An in situ spectroscopy approach. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2019.104562] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Rodrigues RM, Avelar Z, Vicente AA, Petersen SB, Pereira RN. Influence of moderate electric fields in β-lactoglobulin thermal unfolding and interactions. Food Chem 2020; 304:125442. [DOI: 10.1016/j.foodchem.2019.125442] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/22/2019] [Accepted: 08/28/2019] [Indexed: 12/14/2022]
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10
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Rodrigues RM, Vicente AA, Petersen SB, Pereira RN. Electric field effects on β-lactoglobulin thermal unfolding as a function of pH – Impact on protein functionality. INNOV FOOD SCI EMERG 2019. [DOI: 10.1016/j.ifset.2018.11.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Baliga C, Selmke B, Worobiew I, Borbat P, Sarma SP, Trommer WE, Varadarajan R, Aghera N. CcdB at pH 4 Forms a Partially Unfolded State with a Dry Core. Biophys J 2019; 116:807-817. [PMID: 30777307 DOI: 10.1016/j.bpj.2019.01.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 01/18/2019] [Accepted: 01/23/2019] [Indexed: 12/14/2022] Open
Abstract
pH is an important factor that affects the protein structure, stability, and activity. Here, we probe the nature of the low-pH structural form of the homodimeric CcdB (controller of cell death B) protein. Characterization of CcdB protein at pH 4 and 300 K using circular dichroism spectroscopy, 8-anilino-1-naphthalene-sulphonate binding, and Trp solvation studies suggests that it forms a partially unfolded state with a dry core at equilibrium under these conditions. CcdB remains dimeric at pH 4 as shown by multiple techniques, such as size-exclusion chromatography coupled to multiangle light scattering, analytical ultracentrifugation, and electron paramagnetic resonance. Comparative analysis using two-dimensional 15N-1H heteronuclear single-quantum coherence NMR spectra of CcdB at pH 4 and 7 suggests that the pH 4 and native state have similar but nonidentical structures. Hydrogen-exchange-mass-spectrometry studies demonstrate that the pH 4 state has substantial but anisotropic changes in local stability with core regions close to the dimer interface showing lower protection but some other regions showing higher protection relative to pH 7.
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Affiliation(s)
- Chetana Baliga
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Benjamin Selmke
- Department of Chemistry, TU Kaiserslautern, Kaiserslautern, Germany
| | - Irina Worobiew
- Department of Chemistry, TU Kaiserslautern, Kaiserslautern, Germany
| | - Peter Borbat
- Department of Chemistry and Chemical Biology, ACERT National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York
| | - Siddhartha P Sarma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | | | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Nilesh Aghera
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
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12
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Houwman JA, Westphal AH, Visser AJWG, Borst JW, van Mierlo CPM. Concurrent presence of on- and off-pathway folding intermediates of apoflavodoxin at physiological ionic strength. Phys Chem Chem Phys 2018; 20:7059-7072. [PMID: 29473921 DOI: 10.1039/c7cp07922b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Flavodoxins have a protein topology that can be traced back to the universal ancestor of the three kingdoms of life. Proteins with this type of architecture tend to temporarily misfold during unassisted folding to their native state and form intermediates. Several of these intermediate species are molten globules (MGs), which are characterized by a substantial amount of secondary structure, yet without the tertiary side-chain packing of natively folded proteins. An off-pathway MG is formed at physiological ionic strength in the case of the F44Y variant of Azotobacter vinelandii apoflavodoxin (i.e., flavodoxin without flavin mononucleotide (FMN)). Here, we show that at this condition actually two folding species of this apoprotein co-exist at equilibrium. These species were detected by using a combination of FMN fluorescence quenching upon cofactor binding to the apoprotein and of polarized time-resolved tryptophan fluorescence spectroscopy. Besides the off-pathway MG, we observe the simultaneous presence of an on-pathway folding intermediate, which is native-like. Presence of concurrent intermediates at physiological ionic strength enables future exploration of how aspects of the cellular environment, like for example involvement of chaperones, affect these species.
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Affiliation(s)
- Joseline A Houwman
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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13
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Najor M, Leverson BD, Goossens JL, Kothawala S, Olsen KW, Mota de Freitas D. Folding of G α Subunits: Implications for Disease States. ACS OMEGA 2018; 3:12320-12329. [PMID: 30411001 PMCID: PMC6210069 DOI: 10.1021/acsomega.8b01174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
G-proteins play a central role in signal transduction by fluctuating between "on" and "off" phases that are determined by a conformational change. cAMP is a secondary messenger whose formation is inhibited or stimulated by activated Giα1 or Gsα subunit. We used tryptophan fluorescence, UV/vis spectrophotometry, and circular dichroism to probe distinct structural features within active and inactive conformations from wild-type and tryptophan mutants of Giα1 and Gsα. For all proteins studied, we found that the active conformations were more stable than the inactive conformations, and upon refolding from higher temperatures, activated wild-type subunits recovered significantly more native structure. We also observed that the wild-type subunits partially regained the ability to bind nucleotide. The increased compactness observed upon activation was consistent with the calculated decrease in solvent accessible surface area for wild-type Giα1. We found that as the temperature increased, Gα subunits, which are known to be rich in α-helices, converted to proteins with increased content of β-sheets and random coil. For active conformations from wild-type and tryptophan mutants of Giα1, melting temperatures indicated that denaturation starts around hydrophobic tryptophan microenvironments and then radiates toward tyrosine residues at the surface, followed by alteration of the secondary structure. For Gsα, however, disruption of secondary structure preceded unfolding around tyrosine residues. In the active conformations, a π-cation interaction between essential arginine and tryptophan residues, which was characterized by a fluorescence-measured red shift and modeled by molecular dynamics, was also shown to be a contributor to the stability of Gα subunits. The folding properties of Gα subunits reported here are discussed in the context of diseases associated to G-proteins.
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14
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Mishra P, Jha SK. An Alternatively Packed Dry Molten Globule-like Intermediate in the Native State Ensemble of a Multidomain Protein. J Phys Chem B 2017; 121:9336-9347. [DOI: 10.1021/acs.jpcb.7b07032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Prajna Mishra
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India
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15
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Houwman JA, van Mierlo CPM. Folding of proteins with a flavodoxin-like architecture. FEBS J 2017; 284:3145-3167. [PMID: 28380286 DOI: 10.1111/febs.14077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/13/2017] [Accepted: 04/03/2017] [Indexed: 12/21/2022]
Abstract
The flavodoxin-like fold is a protein architecture that can be traced back to the universal ancestor of the three kingdoms of life. Many proteins share this α-β parallel topology and hence it is highly relevant to illuminate how they fold. Here, we review experiments and simulations concerning the folding of flavodoxins and CheY-like proteins, which share the flavodoxin-like fold. These polypeptides tend to temporarily misfold during unassisted folding to their functionally active forms. This susceptibility to frustration is caused by the more rapid formation of an α-helix compared to a β-sheet, particularly when a parallel β-sheet is involved. As a result, flavodoxin-like proteins form intermediates that are off-pathway to native protein and several of these species are molten globules (MGs). Experiments suggest that the off-pathway species are of helical nature and that flavodoxin-like proteins have a nonconserved transition state that determines the rate of productive folding. Folding of flavodoxin from Azotobacter vinelandii has been investigated extensively, enabling a schematic construction of its folding energy landscape. It is the only flavodoxin-like protein of which cotranslational folding has been probed. New insights that emphasize differences between in vivo and in vitro folding energy landscapes are emerging: the ribosome modulates MG formation in nascent apoflavodoxin and forces this polypeptide toward the native state.
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Affiliation(s)
- Joseline A Houwman
- Laboratory of Biochemistry, Wageningen University and Research, The Netherlands
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16
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Yeh YQ, Liao KF, Shih O, Shiu YJ, Wu WR, Su CJ, Lin PC, Jeng US. Probing the Acid-Induced Packing Structure Changes of the Molten Globule Domains of a Protein near Equilibrium Unfolding. J Phys Chem Lett 2017; 8:470-477. [PMID: 28067527 DOI: 10.1021/acs.jpclett.6b02722] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Using simultaneously scanning small-angle X-ray scattering (SAXS) and UV-vis absorption with integrated online size exclusion chromatography, supplemental with molecular dynamics simulations, we unveil the long-postulated global structure evolution of a model multidomain protein bovine serum albumin (BSA) during acid-induced unfolding. Our results differentiate three global packing structures of the three molten globule domains of BSA, forming three intermediates I1, I2, and E along the unfolding pathway. The I1-I2 transition, overlooked in all previous studies, involves mainly coordinated reorientations across interconnected molten globule subdomains, and the transition activates a critical pivot domain opening of the protein for entering into the E form, with an unexpectedly large unfolding free energy change of -9.5 kcal mol-1, extracted based on the observed packing structural changes. The revealed local packing flexibility and rigidity of the molten globule domains in the E form elucidate how collective motions of the molten globule domains profoundly influence the folding-unfolding pathway of a multidomain protein.
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Affiliation(s)
- Yi-Qi Yeh
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Kuei-Fen Liao
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Orion Shih
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Ying-Jen Shiu
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Wei-Ru Wu
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Chun-Jen Su
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Po-Chang Lin
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
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17
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Acharya N, Mishra P, Jha SK. A dry molten globule-like intermediate during the base-induced unfolding of a multidomain protein. Phys Chem Chem Phys 2017; 19:30207-30216. [DOI: 10.1039/c7cp06614g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An early intermediate during the base-induced unfolding of a multidomain protein resembles a dry molten globule state in which the structure is expanded without core hydration.
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Affiliation(s)
- Nirbhik Acharya
- Physical and Materials Chemistry Division
- CSIR-National Chemical Laboratory
- Pune 411008
- India
| | - Prajna Mishra
- Physical and Materials Chemistry Division
- CSIR-National Chemical Laboratory
- Pune 411008
- India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division
- CSIR-National Chemical Laboratory
- Pune 411008
- India
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18
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Houwman JA, André E, Westphal AH, van Berkel WJH, van Mierlo CPM. The Ribosome Restrains Molten Globule Formation in Stalled Nascent Flavodoxin. J Biol Chem 2016; 291:25911-25920. [PMID: 27784783 PMCID: PMC5207065 DOI: 10.1074/jbc.m116.756205] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/13/2016] [Indexed: 11/06/2022] Open
Abstract
Folding of proteins usually involves intermediates, of which an important type is the molten globule (MG). MGs are ensembles of interconverting conformers that contain (non-)native secondary structure and lack the tightly packed tertiary structure of natively folded globular proteins. Whereas MGs of various purified proteins have been probed to date, no data are available on their presence and/or effect during protein synthesis. To study whether MGs arise during translation, we use ribosome-nascent chain (RNC) complexes of the electron transfer protein flavodoxin. Full-length isolated flavodoxin, which contains a non-covalently bound flavin mononucleotide (FMN) as cofactor, acquires its native α/β parallel topology via a folding mechanism that contains an off-pathway intermediate with molten globular characteristics. Extensive population of this MG state occurs at physiological ionic strength for apoflavodoxin variant F44Y, in which a phenylalanine at position 44 is changed to a tyrosine. Here, we show for the first time that ascertaining the binding rate of FMN as a function of ionic strength can be used as a tool to determine the presence of the off-pathway MG on the ribosome. Application of this methodology to F44Y apoflavodoxin RNCs shows that at physiological ionic strength the ribosome influences formation of the off-pathway MG and forces the nascent chain toward the native state.
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Affiliation(s)
- Joseline A Houwman
- From the Laboratory of Biochemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Estelle André
- From the Laboratory of Biochemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Adrie H Westphal
- From the Laboratory of Biochemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Willem J H van Berkel
- From the Laboratory of Biochemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Carlo P M van Mierlo
- From the Laboratory of Biochemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
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19
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Acharya N, Mishra P, Jha SK. Evidence for Dry Molten Globule-Like Domains in the pH-Induced Equilibrium Folding Intermediate of a Multidomain Protein. J Phys Chem Lett 2016; 7:173-179. [PMID: 26700266 DOI: 10.1021/acs.jpclett.5b02545] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The role of van der Waals (vdW) packing interactions compared to the hydrophobic effect in stabilizing the functional structure of proteins is poorly understood. Here we show, using fluorescence resonance energy transfer, dynamic fluorescence quenching, red-edge excitation shift, and near- and far-UV circular dichroism, that the pH-induced structural perturbation of a multidomain protein leads to the formation of a state in which two out of the three domains have characteristics of dry molten globules, that is, the domains are expanded compared to the native protein with disrupted packing interactions but have dry cores. We quantitatively estimate the energetic contribution of vdW interactions and show that they play an important role in the stability of the native state and cooperativity of its structural transition, in addition to the hydrophobic effect. Our results also indicate that during the pH-induced unfolding, side-chain unlocking and hydrophobic solvation occur in two distinct steps and not in a concerted manner, as commonly believed.
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Affiliation(s)
- Nirbhik Acharya
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Prajna Mishra
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
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20
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Hamdane D, Velours C, Cornu D, Nicaise M, Lombard M, Fontecave M. A chemical chaperone induces inhomogeneous conformational changes in flexible proteins. Phys Chem Chem Phys 2016; 18:20410-21. [DOI: 10.1039/c6cp03635j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Organic osmolytes are major cellular compounds that favor protein's compaction and stabilization of the native state. Here, we have examined the chaperone effect of the naturally occurring trimethylamine N-oxide (TMAO) osmolyte on a flexible protein.
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Affiliation(s)
- Djemel Hamdane
- Laboratoire de Chimie des Processus Biologiques
- CNRS-UMR 8229
- Collège De France
- 75231 Paris Cedex 05
- France
| | - Christophe Velours
- Macromolecular Interaction Platform of I2BC
- UMR 9198
- Centre de Recherche de Gif
- Centre National de la Recherche Scientifique
- 91191 Gif Sur Yvette
| | - David Cornu
- CNRS
- Centre de Recherche de Gif
- SICaPS
- F-91198 Gif-sur-Yvette Cedex
- France
| | - Magali Nicaise
- Macromolecular Interaction Platform of I2BC
- UMR 9198
- Centre de Recherche de Gif
- Centre National de la Recherche Scientifique
- 91191 Gif Sur Yvette
| | - Murielle Lombard
- Laboratoire de Chimie des Processus Biologiques
- CNRS-UMR 8229
- Collège De France
- 75231 Paris Cedex 05
- France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques
- CNRS-UMR 8229
- Collège De France
- 75231 Paris Cedex 05
- France
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21
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Roy S, Basu S, Dasgupta D, Bhattacharyya D, Banerjee R. The Unfolding MD Simulations of Cyclophilin: Analyzed by Surface Contact Networks and Their Associated Metrics. PLoS One 2015; 10:e0142173. [PMID: 26545107 PMCID: PMC4636149 DOI: 10.1371/journal.pone.0142173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 10/18/2015] [Indexed: 11/19/2022] Open
Abstract
Currently, considerable interest exists with regard to the dissociation of close packed aminoacids within proteins, in the course of unfolding, which could result in either wet or dry moltenglobules. The progressive disjuncture of residues constituting the hydrophobic core ofcyclophilin from L. donovani (LdCyp) has been studied during the thermal unfolding of the molecule, by molecular dynamics simulations. LdCyp has been represented as a surface contactnetwork (SCN) based on the surface complementarity (Sm) of interacting residues within themolecular interior. The application of Sm to side chain packing within proteins make it a very sensitive indicator of subtle perturbations in packing, in the thermal unfolding of the protein. Network based metrics have been defined to track the sequential changes in the disintegration ofthe SCN spanning the hydrophobic core of LdCyp and these metrics prove to be highly sensitive compared to traditional metrics in indicating the increased conformational (and dynamical) flexibility in the network. These metrics have been applied to suggest criteria distinguishing DMG, WMG and transition state ensembles and to identify key residues involved in crucial conformational/topological events during the unfolding process.
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Affiliation(s)
- Sourav Roy
- Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata, 700064 India
| | - Sankar Basu
- Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata, 700064 India
| | - Dipak Dasgupta
- Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata, 700064 India
| | - Dhananjay Bhattacharyya
- Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata, 700064 India
- * E-mail: (DB); (RB)
| | - Rahul Banerjee
- Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata, 700064 India
- * E-mail: (DB); (RB)
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22
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Lindhoud S, Pirchi M, Westphal AH, Haran G, van Mierlo CPM. Gradual Folding of an Off-Pathway Molten Globule Detected at the Single-Molecule Level. J Mol Biol 2015; 427:3148-57. [PMID: 26163276 DOI: 10.1016/j.jmb.2015.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 05/27/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
Abstract
Molten globules (MGs) are compact, partially folded intermediates that are transiently present during folding of many proteins. These intermediates reside on or off the folding pathway to native protein. Conformational evolution during folding of off-pathway MGs is largely unexplored. Here, we characterize the denaturant-dependent structure of apoflavodoxin's off-pathway MG. Using single-molecule fluorescence resonance energy transfer (smFRET), we follow conversion of unfolded species into MG down to denaturant concentrations that favor formation of native protein. Under strongly denaturing conditions, fluorescence resonance energy transfer histograms show a single peak, arising from unfolded protein. The smFRET efficiency distribution shifts to higher value upon decreasing denaturant concentration because the MG folds. Strikingly, upon approaching native conditions, the fluorescence resonance energy transfer efficiency of the MG rises above that of native protein. Thus, smFRET exposes the misfolded nature of apoflavodoxin's off-pathway MG. We show that conversion of unfolded into MG protein is a gradual, second-order-like process that simultaneously involves separate regions within the polypeptide.
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Affiliation(s)
- Simon Lindhoud
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, the Netherlands
| | - Menahem Pirchi
- Chemical Physics Department, Weizmann Institute of Science, Herzl St 234, Rehovot 76100, Israel
| | - Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, the Netherlands
| | - Gilad Haran
- Chemical Physics Department, Weizmann Institute of Science, Herzl St 234, Rehovot 76100, Israel.
| | - Carlo P M van Mierlo
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, the Netherlands.
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23
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Naiyer A, Hassan MI, Islam A, Sundd M, Ahmad F. Structural characterization of MG and pre-MG states of proteins by MD simulations, NMR, and other techniques. J Biomol Struct Dyn 2015; 33:2267-84. [PMID: 25586676 DOI: 10.1080/07391102.2014.999354] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Almost all proteins fold via a number of partially structured intermediates such as molten globule (MG) and pre-molten globule states. Understanding the structure of these intermediates at atomic level is often a challenge, as these states are observed under extreme conditions of pH, temperature, and chemical denaturants. Furthermore, several other processes such as chemical modification, site-directed mutagenesis (or point mutation), and cleavage of covalent bond of natural proteins often lead to MG like partially unfolded conformation. However, the dynamic nature of proteins in these states makes them unsuitable for most structure determination at atomic level. Intermediate states studied so far have been characterized mostly by circular dichroism, fluorescence, viscosity, dynamic light scattering measurements, dye binding, infrared techniques, molecular dynamics simulations, etc. There is a limited amount of structural data available on these intermediate states by nuclear magnetic resonance (NMR) and hence there is a need to characterize these states at the molecular level. In this review, we present characterization of equilibrium intermediates by biophysical techniques with special reference to NMR.
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Affiliation(s)
- Abdullah Naiyer
- a Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi - 110025 , India
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24
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Hoang J, Prosser RS. Conformational Selection and Functional Dynamics of Calmodulin: A 19F Nuclear Magnetic Resonance Study. Biochemistry 2014; 53:5727-36. [DOI: 10.1021/bi500679c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Joshua Hoang
- Department
of Chemistry, University of Toronto, UTM, 3359 Mississauga Road North, Mississauga, ON L5L 1C6, Canada
| | - R. Scott Prosser
- Department
of Chemistry, University of Toronto, UTM, 3359 Mississauga Road North, Mississauga, ON L5L 1C6, Canada
- Department
of Biochemistry, University of Toronto, 1 King’s College Circle, Toronto, ON M5S
1A8, Canada
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25
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Kang D, Ryu SR, Park Y, Czarnik-Matusewicz B, Jung YM. pH-induced structural changes of ovalbumin studied by 2D correlation IR spectroscopy. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.02.061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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26
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Malhotra P, Udgaonkar JB. High-Energy Intermediates in Protein Unfolding Characterized by Thiol Labeling under Nativelike Conditions. Biochemistry 2014; 53:3608-20. [DOI: 10.1021/bi401493t] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pooja Malhotra
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Jayant B. Udgaonkar
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
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27
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Jha SK, Marqusee S. Kinetic evidence for a two-stage mechanism of protein denaturation by guanidinium chloride. Proc Natl Acad Sci U S A 2014; 111:4856-61. [PMID: 24639503 PMCID: PMC3977270 DOI: 10.1073/pnas.1315453111] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dry molten globular (DMG) intermediates, an expanded form of the native protein with a dry core, have been observed during denaturant-induced unfolding of many proteins. These observations are counterintuitive because traditional models of chemical denaturation rely on changes in solvent-accessible surface area, and there is no notable change in solvent-accessible surface area during the formation of the DMG. Here we show, using multisite fluorescence resonance energy transfer, far-UV CD, and kinetic thiol-labeling experiments, that the guanidinium chloride (GdmCl)-induced unfolding of RNase H also begins with the formation of the DMG. Population of the DMG occurs within the 5-ms dead time of our measurements. We observe that the size and/or population of the DMG is linearly dependent on [GdmCl], although not as strongly as the second and major step of unfolding, which is accompanied by core solvation and global unfolding. This rapid GdmCl-dependent population of the DMG indicates that GdmCl can interact with the protein before disrupting the hydrophobic core. These results imply that the effect of chemical denaturants cannot be interpreted solely as a disruption of the hydrophobic effect and strongly support recent computational studies, which hypothesize that chemical denaturants first interact directly with the protein surface before completely unfolding the protein in the second step (direct interaction mechanism).
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Affiliation(s)
| | - Susan Marqusee
- California Institute for Quantitative Biosciences and
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3220
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28
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Litwińczuk A, Ryu SR, Nafie LA, Lee JW, Kim HI, Jung YM, Czarnik-Matusewicz B. The transition from the native to the acid-state characterized by multi-spectroscopy approach: study for the holo-form of bovine α-lactalbumin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:593-606. [PMID: 24389233 DOI: 10.1016/j.bbapap.2013.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 12/09/2013] [Accepted: 12/24/2013] [Indexed: 12/26/2022]
Abstract
The transition of the holo-form of bovine α-lactalbumin from the native (N) to the pH-generated acidic-state (A-state) was analyzed by probing its tertiary and secondary structure using a concerted spectroscopic approach combining near- and far-UV circular dichroism (CD), electrospray ionization ion mobility mass spectrometry (ESI-IM-MS), vibrational circular dichroism (VCD), and Fourier transform infrared spectroscopy (FTIR) in the attenuated total reflection (ATR) and transmission (TR) modes. The spectroscopic results, which relied on the interaction of an electromagnetic field with different molecular targets, confirmed the decay of extensive rigid side-chain packing interactions during the pH-induced N→A-state transition and revealed the targets' dependence on secondary structural changes. Independent analyses of the spectral changes using two methods of multivariate analysis, such as principal component analysis and two-dimensional correlation spectroscopy, revealed small but significant differences in the secondary structure as a result of the all-or-none transition. The cooperativity of the transition was quantitatively described using values corresponding to the mid-point (tm) and width of the transition (Δtm). The averages of the two parameters, calculated using the data collected by the different probes, were equal to 3.5±0.2 and 0.6±0.1(SE), respectively. The variable two-state nature of the cooperative N→A-state transition confirmed that the protonation of the side chain carboxyl groups on the Asp and Glu residues and that the release of a Ca(2+) ion induced structural changes on both the secondary and tertiary levels. The changes have been confirmed by results obtained from the concerted spectroscopic approach.
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Affiliation(s)
- Adriana Litwińczuk
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Soo Ryeon Ryu
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chunchon 200-701, Republic of Korea
| | - Laurence A Nafie
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA
| | - Jong Wha Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Hugh I Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea; Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Young Mee Jung
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chunchon 200-701, Republic of Korea.
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29
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Compiani M, Capriotti E. Computational and theoretical methods for protein folding. Biochemistry 2013; 52:8601-24. [PMID: 24187909 DOI: 10.1021/bi4001529] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A computational approach is essential whenever the complexity of the process under study is such that direct theoretical or experimental approaches are not viable. This is the case for protein folding, for which a significant amount of data are being collected. This paper reports on the essential role of in silico methods and the unprecedented interplay of computational and theoretical approaches, which is a defining point of the interdisciplinary investigations of the protein folding process. Besides giving an overview of the available computational methods and tools, we argue that computation plays not merely an ancillary role but has a more constructive function in that computational work may precede theory and experiments. More precisely, computation can provide the primary conceptual clues to inspire subsequent theoretical and experimental work even in a case where no preexisting evidence or theoretical frameworks are available. This is cogently manifested in the application of machine learning methods to come to grips with the folding dynamics. These close relationships suggested complementing the review of computational methods within the appropriate theoretical context to provide a self-contained outlook of the basic concepts that have converged into a unified description of folding and have grown in a synergic relationship with their computational counterpart. Finally, the advantages and limitations of current computational methodologies are discussed to show how the smart analysis of large amounts of data and the development of more effective algorithms can improve our understanding of protein folding.
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Affiliation(s)
- Mario Compiani
- School of Sciences and Technology, University of Camerino , Camerino, Macerata 62032, Italy
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30
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Circular dichroism and site-directed spin labeling reveal structural and dynamical features of high-pressure states of myoglobin. Proc Natl Acad Sci U S A 2013; 110:E4714-22. [PMID: 24248390 DOI: 10.1073/pnas.1320124110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Excited states of proteins may play important roles in function, yet are difficult to study spectroscopically because of their sparse population. High hydrostatic pressure increases the equilibrium population of excited states, enabling their characterization [Akasaka K (2003) Biochemistry 42:10875-85]. High-pressure site-directed spin-labeling EPR (SDSL-EPR) was developed recently to map the site-specific structure and dynamics of excited states populated by pressure. To monitor global secondary structure content by circular dichroism (CD) at high pressure, a modified optical cell using a custom MgF2 window with a reduced aperture is introduced. Here, a combination of SDSL-EPR and CD is used to map reversible structural transitions in holomyoglobin and apomyoglobin (apoMb) as a function of applied pressure up to 2 kbar. CD shows that the high-pressure excited state of apoMb at pH 6 has helical content identical to that of native apoMb, but reversible changes reflecting the appearance of a conformational ensemble are observed by SDSL-EPR, suggesting a helical topology that fluctuates slowly on the EPR time scale. Although the high-pressure state of apoMb at pH 6 has been referred to as a molten globule, the data presented here reveal significant differences from the well-characterized pH 4.1 molten globule of apoMb. Pressure-populated states of both holomyoglobin and apoMb at pH 4.1 have significantly less helical structure, and for the latter, that may correspond to a transient folding intermediate.
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31
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Yamasaki K, Obara Y, Hasegawa M, Tanaka H, Yamasaki T, Wakuda T, Okada M, Kohzuma T. Real-Time NMR Monitoring of Protein-Folding Kinetics by a Recycle Flow System for Temperature Jump. Anal Chem 2013; 85:9439-43. [DOI: 10.1021/ac401579e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kazuhiko Yamasaki
- Biomedical Research
Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yuji Obara
- Institute of Applied
Beam Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan
| | - Manabu Hasegawa
- Hitachi Research
Laboratory, Hitachi, Ltd., 7-1-1 Omika-cho, Hitachi, Ibaraki 319-1292, Japan
| | - Hideki Tanaka
- Hitachi Research
Laboratory, Hitachi, Ltd., 7-1-1 Omika-cho, Hitachi, Ibaraki 319-1292, Japan
| | - Tomoko Yamasaki
- Biomedical Research
Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Tsuyoshi Wakuda
- Hitachi Research
Laboratory, Hitachi, Ltd., 7-1-1 Omika-cho, Hitachi, Ibaraki 319-1292, Japan
| | - Michiya Okada
- Tsukuba Innovation
Arena, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8562, Japan
| | - Takamitsu Kohzuma
- Institute of Applied
Beam Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan
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