1
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Chang R, Gruebele M, Leckband DE. Protein Folding Stability and Kinetics in Alginate Hydrogels. Biomacromolecules 2023; 24:5245-5254. [PMID: 37906737 DOI: 10.1021/acs.biomac.3c00764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Proteins are commonly encapsulated in alginate gels for drug delivery and tissue-engineering applications. However, there is limited knowledge of how encapsulation impacts intrinsic protein properties such as folding stability or unfolding kinetics. Here, we use fast relaxation imaging (FReI) to image protein unfolding in situ in alginate hydrogels after applying a temperature jump. Based on changes in the Förster resonance energy transfer (FRET) response of FRET-labeled phosphoglycerate kinase (PGK), we report the quantitative impact of multiple alginate hydrogel concentrations on protein stability and folding dynamics. The gels stabilize PGK by increasing its melting temperature up to 18.4 °C, and the stabilization follows a nonmonotonic dependence on the alginate density. In situ kinetic measurements also reveal that PGK deviates more from two-state folding behavior in denser gels and that the gel decreases the unfolding rate and accelerates the folding rate of PGK, compared to buffer. Phi-value analysis suggests that the folding transition state of an encapsulated protein is structurally similar to that of folded protein. This work reveals both beneficial and negative impacts of gel encapsulation on protein folding, as well as potential mechanisms contributing to altered stability.
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2
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Vergara R, Berrocal T, Juárez Mejía EI, Romero-Romero S, Velázquez-López I, Pulido NO, López Sanchez HA, Silva DA, Costas M, Rodríguez-Romero A, Rodríguez-Sotres R, Sosa-Peinado A, Fernández-Velasco DA. Thermodynamic and kinetic analysis of the LAO binding protein and its isolated domains reveal non-additivity in stability, folding and function. FEBS J 2023; 290:4496-4512. [PMID: 37178351 DOI: 10.1111/febs.16819] [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: 03/29/2023] [Accepted: 05/12/2023] [Indexed: 05/15/2023]
Abstract
Substrate-binding proteins (SBPs) are used by organisms from the three domains of life for transport and signalling. SBPs are composed of two domains that collectively trap ligands with high affinity and selectivity. To explore the role of the domains and the integrity of the hinge region between them in the function and conformation of SBPs, here, we describe the ligand binding, conformational stability and folding kinetics of the Lysine Arginine Ornithine (LAO) binding protein from Salmonella thiphimurium and constructs corresponding to its two independent domains. LAO is a class II SBP formed by a continuous and a discontinuous domain. Contrary to the expected behaviour based on their connectivity, the discontinuous domain shows a stable native-like structure that binds l-arginine with moderate affinity, whereas the continuous domain is barely stable and shows no detectable ligand binding. Regarding folding kinetics, studies of the entire protein revealed the presence of at least two intermediates. While the unfolding and refolding of the continuous domain exhibited only a single intermediate and simpler and faster kinetics than LAO, the folding mechanism of the discontinuous domain was complex and involved multiple intermediates. These findings suggest that in the complete protein the continuous domain nucleates folding and that its presence funnels the folding of the discontinuous domain avoiding nonproductive interactions. The strong dependence of the function, stability and folding pathway of the lobes on their covalent association is most likely the result of the coevolution of both domains as a single unit.
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Affiliation(s)
- Renan Vergara
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Tania Berrocal
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Eva Isela Juárez Mejía
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Sergio Romero-Romero
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- Department of Biochemistry, University of Bayreuth, Germany
| | - Isabel Velázquez-López
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Nancy O Pulido
- Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Haven A López Sanchez
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Daniel-Adriano Silva
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Miguel Costas
- Laboratorio de Biofisicoquímica, Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Rogelio Rodríguez-Sotres
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Alejandro Sosa-Peinado
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - D Alejandro Fernández-Velasco
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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3
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Protein folding in vitro and in the cell: From a solitary journey to a team effort. Biophys Chem 2022; 287:106821. [PMID: 35667131 PMCID: PMC9636488 DOI: 10.1016/j.bpc.2022.106821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/18/2022] [Accepted: 04/21/2022] [Indexed: 12/22/2022]
Abstract
Correct protein folding is essential for the health and function of living organisms. Yet, it is not well understood how unfolded proteins reach their native state and avoid aggregation, especially within the cellular milieu. Some proteins, especially small, single-domain and apparent two-state folders, successfully attain their native state upon dilution from denaturant. Yet, many more proteins undergo misfolding and aggregation during this process, in a concentration-dependent fashion. Once formed, native and aggregated states are often kinetically trapped relative to each other. Hence, the early stages of protein life are absolutely critical for proper kinetic channeling to the folded state and for long-term solubility and function. This review summarizes current knowledge on protein folding/aggregation mechanisms in buffered solution and within the bacterial cell, highlighting early stages. Remarkably, teamwork between nascent chain, ribosome, trigger factor and Hsp70 molecular chaperones enables all proteins to overcome aggregation propensities and reach a long-lived bioactive state.
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4
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Mora-Sierra Z, Gopan G, Chang R, Leckband DE, Gruebele M. Stabilization and Kinetics of an Adsorbed Protein Depends on the Poly( N-isopropylacrylamide) Grafting Density. Biomacromolecules 2021; 22:4470-4478. [PMID: 34606244 DOI: 10.1021/acs.biomac.1c00417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solubility transition at the lower critical solution temperature (LCST, 32 °C) of poly(N-isopropylacrylamide) (PNIPAM) is widely used as a thermal switch to rapidly and reversibly capture and release proteins and cells. It is generally assumed that proteins adsorbed to PNIPAM above the LCST are unaffected by polymer interactions. Here we show that the folding stability of the enzyme phosphoglycerate kinase (PGK) is increased by interactions with end-grafted PNIPAM films above the LCST. We systematically compare two protein mutants with different stabilities. The stabilization mirrors the degree of protein adsorption under grafting conditions studied previously. Maximum stabilization occurs when proteins adsorb to low density, collapsed polymer "mushrooms". In the denser polymer "brush" regime, protein stabilization decreases back to a value indistinguishable from the bulk solution, consistent with low protein adsorption on dense, collapsed brushes. The temperature-dependent kinetics measured by Fast Relaxation Imaging reveals that PNIPAM does not affect the overall folding/unfolding mechanism. Based on the different stabilizations of two mutants and the relaxation kinetics, we hypothesize that the polymer acts mainly by increasing the conformational entropy of the folded protein by interacting with the protein surface and less by crowding the unfolded state of PGK.
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5
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Helmick H, Nanda G, Ettestad S, Liceaga A, Kokini JL. Applying text mining to identify relevant literature in food science: Cold denaturation as a case study. J Food Sci 2021; 86:4851-4864. [PMID: 34653257 DOI: 10.1111/1750-3841.15940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 11/28/2022]
Abstract
In a research environment characterized by the five V's of big data, volume, velocity, variety, value, and veracity, the need to develop tools that quickly screen a large number of publications into relevant work is an increasing area of concern, and the data-rich food industry is no exception. Here, a combination of latent Dirichlet allocation and food keyword searches were employed to analyze and filter a dataset of 6102 publications about cold denaturation. After using the Python toolkit generated in this work, the approach yielded 22 topics that provide background and insight on the direction of research in this field, as well as identified the publications in this dataset which are most pertinent to the food industry with precision and recall of 0.419 and 0.949, respectively. Precision is related to the relevance of a paper in the filtered dataset and the recall represents papers which were not identified in the screening method. Lastly, gaps in the literature based on keyword trends are identified to improve the knowledge base of cold denaturation as it relates to the food industry. This approach is generalizable to any similarly organized dataset, and the code is available upon request. Practical Application: A common problem in research is that when you are an expert in one field, learning about another field is difficult, because you may lack the vocabulary and background needed to read cutting edge literature from a new discipline. The Python toolkit developed in this research can be applied by any researcher that is new to a field to identify what the key literature is, what topics they should familiarize themselves with, and what the current trends are in the field. Using this structure, researchers can greatly speed up how they identify new areas to research and find new projects.
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Affiliation(s)
- Harrison Helmick
- Purdue University Food Science Department, West Lafayette, Indiana, USA
| | - Gaurav Nanda
- Purdue University Food Science Department, West Lafayette, Indiana, USA
| | - Sarah Ettestad
- Purdue University Food Science Department, West Lafayette, Indiana, USA
| | - Andrea Liceaga
- Purdue University Food Science Department, West Lafayette, Indiana, USA
| | - Jozef L Kokini
- Purdue University Food Science Department, West Lafayette, Indiana, USA
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6
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Pagano L, Malagrinò F, Visconti L, Troilo F, Pennacchietti V, Nardella C, Toto A, Gianni S. Probing the Effects of Local Frustration in the Folding of a Multidomain Protein. J Mol Biol 2021; 433:167087. [PMID: 34089717 DOI: 10.1016/j.jmb.2021.167087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/22/2021] [Accepted: 05/28/2021] [Indexed: 11/28/2022]
Abstract
Our current knowledge of protein folding is primarily based on experimental data obtained from isolated domains. In fact, because of their complexity, multidomain proteins have been elusive to the experimental characterization. Thus, the folding of a domain in isolation is generally assumed to resemble what should be observed for more complex structural architectures. Here we compared the folding mechanism of a protein domain in isolation and in the context of its supramodular multidomain structure. By carrying out an extensive mutational analysis we illustrate that while the early events of folding are malleable and influenced by the absence/presence of the neighboring structures, the late events appear to be more robust. These effects may be explained by analyzing the local frustration patterns of the domain, providing critical support for the funneled energy landscape theory of protein folding, and highlighting the role of protein frustration in sculpting the early events of the reaction.
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Affiliation(s)
- Livia Pagano
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Francesca Malagrinò
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Lorenzo Visconti
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Francesca Troilo
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Valeria Pennacchietti
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Caterina Nardella
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy
| | - Angelo Toto
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy.
| | - Stefano Gianni
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185 Rome, Italy.
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7
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Gruebele M. Protein folding and surface interaction phase diagrams in vitro and in cells. FEBS Lett 2021; 595:1267-1274. [PMID: 33576021 DOI: 10.1002/1873-3468.14058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 11/11/2022]
Abstract
Protein stability is subject to environmental perturbations such as pressure and crowding, as well as sticking to other macromolecules and quinary structure. Thus, the environment inside and outside the cell plays a key role in how proteins fold, interact, and function on the scale from a few molecules to macroscopic ensembles. This review discusses three aspects of protein phase diagrams: first, the relevance of phase diagrams to protein folding and function in vitro and in cells; next, how the evolution of protein surfaces impacts on interaction phase diagrams; and finally, how phase separation plays a role on much larger length-scales than individual proteins or oligomers, when liquid phase-separated regions form to assist protein function and cell homeostasis.
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Affiliation(s)
- Martin Gruebele
- Department of Chemistry and Physics, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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8
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Chu X, Suo Z, Wang J. Investigating the trade-off between folding and function in a multidomain Y-family DNA polymerase. eLife 2020; 9:60434. [PMID: 33079059 PMCID: PMC7641590 DOI: 10.7554/elife.60434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/16/2020] [Indexed: 01/01/2023] Open
Abstract
The way in which multidomain proteins fold has been a puzzling question for decades. Until now, the mechanisms and functions of domain interactions involved in multidomain protein folding have been obscure. Here, we develop structure-based models to investigate the folding and DNA-binding processes of the multidomain Y-family DNA polymerase IV (DPO4). We uncover shifts in the folding mechanism among ordered domain-wise folding, backtracking folding, and cooperative folding, modulated by interdomain interactions. These lead to ‘U-shaped’ DPO4 folding kinetics. We characterize the effects of interdomain flexibility on the promotion of DPO4–DNA (un)binding, which probably contributes to the ability of DPO4 to bypass DNA lesions, which is a known biological role of Y-family polymerases. We suggest that the native topology of DPO4 leads to a trade-off between fast, stable folding and tight functional DNA binding. Our approach provides an effective way to quantitatively correlate the roles of protein interactions in conformational dynamics at the multidomain level.
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Affiliation(s)
- Xiakun Chu
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
| | - Zucai Suo
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, United States
| | - Jin Wang
- Department of Chemistry, State University of New York at Stony Brook, New York, United States
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9
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Cerminara M, Schöne A, Ritter I, Gabba M, Fitter J. Mapping Multiple Distances in a Multidomain Protein for the Identification of Folding Intermediates. Biophys J 2020; 118:688-697. [PMID: 31916943 PMCID: PMC7002912 DOI: 10.1016/j.bpj.2019.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/13/2019] [Accepted: 12/10/2019] [Indexed: 10/27/2022] Open
Abstract
The investigation and understanding of the folding mechanism of multidomain proteins is still a challenge in structural biology. The use of single-molecule Förster resonance energy transfer offers a unique tool to map conformational changes within the protein structure. Here, we present a study following denaturant-induced unfolding transitions of yeast phosphoglycerate kinase by mapping several inter- and intradomain distances of this two-domain protein, exhibiting a quite heterogeneous behavior. On the one hand, the development of the interdomain distance during the unfolding transition suggests a classical two-state unfolding behavior. On the other hand, the behavior of some intradomain distances indicates the formation of a compact and transient molten globule intermediate state. Furthermore, different intradomain distances measured within the same domain show pronounced differences in their unfolding behavior, underlining the fact that the choice of dye attachment positions within the polypeptide chain has a substantial impact on which unfolding properties are observed by single-molecule Förster resonance energy transfer measurements. Our results suggest that, to fully characterize the complex folding and unfolding mechanism of multidomain proteins, it is necessary to monitor multiple intra- and interdomain distances because a single reporter can lead to a misleading, partial, or oversimplified interpretation.
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Affiliation(s)
- Michele Cerminara
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany.
| | - Antonie Schöne
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany
| | - Ilona Ritter
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany
| | - Matteo Gabba
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany
| | - Jörg Fitter
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany; RWTH Aachen University, I. Physikalisches Institut (IA), Aachen, Germany.
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10
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Li Q, Scholl ZN, Marszalek PE. Unraveling the Mechanical Unfolding Pathways of a Multidomain Protein: Phosphoglycerate Kinase. Biophys J 2019; 115:46-58. [PMID: 29972811 DOI: 10.1016/j.bpj.2018.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/31/2018] [Accepted: 05/21/2018] [Indexed: 01/12/2023] Open
Abstract
Phosphoglycerate kinase (PGK) is a highly conserved enzyme that is crucial for glycolysis. PGK is a monomeric protein composed of two similar domains and has been the focus of many studies for investigating interdomain interactions within the native state and during folding. Previous studies used traditional biophysical methods (such as circular dichroism, tryptophan fluorescence, and NMR) to measure signals over a large ensemble of molecules, which made it difficult to observe transient changes in stability or structure during unfolding and refolding of single molecules. Here, we unfold single molecules of PGK using atomic force spectroscopy and steered molecular dynamic computer simulations to examine the conformational dynamics of PGK during its unfolding process. Our results show that after the initial forced separation of its domains, yeast PGK (yPGK) does not follow a single mechanical unfolding pathway; instead, it stochastically follows two distinct pathways: unfolding from the N-terminal domain or unfolding from the C-terminal domain. The truncated yPGK N-terminal domain unfolds via a transient intermediate, whereas the structurally similar isolated C-terminal domain has no detectable intermediates throughout its mechanical unfolding process. The N-terminal domain in the full-length yPGK displays a strong unfolding intermediate 13% of the time, whereas the truncated domain (yPGKNT) transitions through the intermediate 81% of the time. This effect indicates that the mechanical properties of yPGK cannot be simply deduced from the mechanical properties of its constituents. We also find that Escherichia coli PGK is significantly less mechanically stable as compared to yPGK, contrary to bulk unfolding measurements. Our results support the growing body of observations that the folding behavior of multidomain proteins is difficult to predict based solely on the studies of isolated domains.
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Affiliation(s)
- Qing Li
- Center for Biologically Inspired Materials and Material Systems, Department of Mechanical Engineering and Materials Science, Pratt School of Engineering, Duke University, Durham, North Carolina.
| | - Zackary N Scholl
- Program in Computational Biology and Bioinformatics, Department of Mechanical Engineering and Materials Science, Pratt School of Engineering, Duke University, Durham, North Carolina.
| | - Piotr E Marszalek
- Center for Biologically Inspired Materials and Material Systems, Department of Mechanical Engineering and Materials Science, Pratt School of Engineering, Duke University, Durham, North Carolina.
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11
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Vishwanath S, de Brevern AG, Srinivasan N. Same but not alike: Structure, flexibility and energetics of domains in multi-domain proteins are influenced by the presence of other domains. PLoS Comput Biol 2018; 14:e1006008. [PMID: 29432415 PMCID: PMC5825166 DOI: 10.1371/journal.pcbi.1006008] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 02/23/2018] [Accepted: 01/29/2018] [Indexed: 02/01/2023] Open
Abstract
The majority of the proteins encoded in the genomes of eukaryotes contain more than one domain. Reasons for high prevalence of multi-domain proteins in various organisms have been attributed to higher stability and functional and folding advantages over single-domain proteins. Despite these advantages, many proteins are composed of only one domain while their homologous domains are part of multi-domain proteins. In the study presented here, differences in the properties of protein domains in single-domain and multi-domain systems and their influence on functions are discussed. We studied 20 pairs of identical protein domains, which were crystallized in two forms (a) tethered to other proteins domains and (b) tethered to fewer protein domains than (a) or not tethered to any protein domain. Results suggest that tethering of domains in multi-domain proteins influences the structural, dynamic and energetic properties of the constituent protein domains. 50% of the protein domain pairs show significant structural deviations while 90% of the protein domain pairs show differences in dynamics and 12% of the residues show differences in the energetics. To gain further insights on the influence of tethering on the function of the domains, 4 pairs of homologous protein domains, where one of them is a full-length single-domain protein and the other protein domain is a part of a multi-domain protein, were studied. Analyses showed that identical and structurally equivalent functional residues show differential dynamics in homologous protein domains; though comparable dynamics between in-silico generated chimera protein and multi-domain proteins were observed. From these observations, the differences observed in the functions of homologous proteins could be attributed to the presence of tethered domain. Overall, we conclude that tethered domains in multi-domain proteins not only provide stability or folding advantages but also influence pathways resulting in differences in function or regulatory properties. High prevalence of multi-domain proteins in proteomes has been attributed to higher stability and functional and folding advantages of the multi-domain proteins. Influence of tethering of domains on the overall properties of proteins has been well studied but its influence on the properties of the constituent domains is largely unaddressed. Here, we investigate the influence of tethering of domains in multi-domain proteins on the structural, dynamics and energetics properties of the constituent domains and its implications on the functions of proteins. To this end, comparative analyses were carried out for identical protein domains crystallized in tethered and untethered forms. Also, comparative analyses of single-domain proteins and their homologous multi-domain proteins were performed. The analyses suggest that tethering influences the structural, dynamic and energetic properties of constituent protein domains. Our observations hint at regulation of protein domains by tethered domains in multi-domain systems, which may manifest at the differential function observed between single-domain and homologous multi-domain proteins.
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Grants
- IISc-DBT partnership programme
- DST, India (Mathematical Biology Initiative & J.C. Bose National Fellowship, FIST program)
- UGC, India – Centre for Advanced Studies
- Ministry of Human Resource Development
- Ministry of Research (France), University of Paris Diderot, Sorbonne Paris Cité
- National Institute for Blood Transfusion (INTS, France), Institute for Health and Medical Research (INSERM, France), Laboratory of Excellence GR-Ex
- The labex GR-Ex is funded by the program Investissements d’avenir of the French National Research Agency,
- Indo-French Centre for the Promotion of Advanced Research/CEFIPRA for a collaborative grant
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Affiliation(s)
- Sneha Vishwanath
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Alexandre G. de Brevern
- INSERM, U 1134, DSIMB, Paris, France
- Univ. Paris Diderot, Sorbonne Paris Cité, Univ de la Réunion, Univ des Antilles, UMR_S 1134, Paris, France
- Institut National de la Transfusion Sanguine (INTS), Paris, France
- Laboratoire d' Excellence GR-Ex, Paris, France
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12
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Zhang Y, Yates EV, Hong L, Saar KL, Meisl G, Dobson CM, Knowles TPJ. On-chip measurements of protein unfolding from direct observations of micron-scale diffusion. Chem Sci 2018; 9:3503-3507. [PMID: 29780480 PMCID: PMC5934698 DOI: 10.1039/c7sc04331g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/09/2018] [Indexed: 11/26/2022] Open
Abstract
The unfolding process of BSA in solution as a function of pH was studied by microfluidic diffusional sizing device.
Investigations of protein folding, unfolding and stability are critical for the understanding of the molecular basis of biological structure and function. We describe here a microfluidic approach to probe the unfolding of unlabelled protein molecules in microliter volumes. We achieve this objective through the use of a microfluidic platform, which allows the changes in molecular diffusivity upon folding and unfolding to be detected directly. We illustrate this approach by monitoring the unfolding of bovine serum albumin in solution as a function of pH. These results show the viability of probing protein stability on chip in small volumes.
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Affiliation(s)
- Yuewen Zhang
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344
| | - Emma V Yates
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344
| | - Liu Hong
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344.,Zhou Pei-Yuan Center for Applied Mathematics , Tsinghua University , Beijing , 10084 , P. R. China
| | - Kadi L Saar
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344
| | - Georg Meisl
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344
| | - Christopher M Dobson
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344
| | - Tuomas P J Knowles
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . ; ; Tel: +44 (0)1223 336344.,Cavendish Laboratory , University of Cambridge , J J Thomson Avenue , Cambridge , CB3 0HE , UK
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13
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Levy Y. Protein Assembly and Building Blocks: Beyond the Limits of the LEGO Brick Metaphor. Biochemistry 2017; 56:5040-5048. [PMID: 28809494 DOI: 10.1021/acs.biochem.7b00666] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Proteins, like other biomolecules, have a modular and hierarchical structure. Various building blocks are used to construct proteins of high structural complexity and diverse functionality. In multidomain proteins, for example, domains are fused to each other in different combinations to achieve different functions. Although the LEGO brick metaphor is justified as a means of simplifying the complexity of three-dimensional protein structures, several fundamental properties (such as allostery or the induced-fit mechanism) make deviation from it necessary to respect the plasticity, softness, and cross-talk that are essential to protein function. In this work, we illustrate recently reported protein behavior in multidomain proteins that deviates from the LEGO brick analogy. While earlier studies showed that a protein domain is often unaffected by being fused to another domain or becomes more stable following the formation of a new interface between the tethered domains, destabilization due to tethering has been reported for several systems. We illustrate that tethering may sometimes result in a multidomain protein behaving as "less than the sum of its parts". We survey these cases for which structure additivity does not guarantee thermodynamic additivity. Protein destabilization due to fusion to other domains may be linked in some cases to biological function and should be taken into account when designing large assemblies.
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Affiliation(s)
- Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science , Rehovot 76100, Israel
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14
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Wu CC, Kannan K, Lin S, Yen L, Milosavljevic A. Identification of cancer fusion drivers using network fusion centrality. ACTA ACUST UNITED AC 2013; 29:1174-81. [PMID: 23505294 DOI: 10.1093/bioinformatics/btt131] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SUMMARY Gene fusions are being discovered at an increasing rate using massively parallel sequencing technologies. Prioritization of cancer fusion drivers for validation cannot be performed using traditional single-gene based methods because fusions involve portions of two partner genes. To address this problem, we propose a novel network analysis method called fusion centrality that is specifically tailored for prioritizing gene fusions. We first propose a domain-based fusion model built on the theory of exon/domain shuffling. The model leads to a hypothesis that a fusion is more likely to be an oncogenic driver if its partner genes act like hubs in a network because the fusion mutation can deregulate normal functions of many other genes and their pathways. The hypothesis is supported by the observation that for most known cancer fusion genes, at least one of the fusion partners appears to be a hub in a network, and even for many fusions both partners appear to be hubs. Based on this model, we construct fusion centrality, a multi-gene-based network metric, and use it to score fusion drivers. We show that the fusion centrality outperforms other single gene-based methods. Specifically, the method successfully predicts most of 38 newly discovered fusions that had validated oncogenic importance. To our best knowledge, this is the first network-based approach for identifying fusion drivers. AVAILABILITY Matlab code implementing the fusion centrality method is available upon request from the corresponding authors.
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Affiliation(s)
- Chia-Chin Wu
- Department of Genomic Medicine, UT MD Anderson Cancer Center, Houston, TX 77030, USA.
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15
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Role of domain interactions in the collective motion of phosphoglycerate kinase. Biophys J 2013; 104:677-82. [PMID: 23442918 DOI: 10.1016/j.bpj.2012.12.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 10/19/2012] [Accepted: 12/13/2012] [Indexed: 11/20/2022] Open
Abstract
Protein function is governed by the underlying conformational dynamics of the molecule. The experimental and theoretical work leading to contemporary understanding of enzyme dynamics was mostly restricted to the large-scale movements of single-domain proteins. Collective movements resulting from a regulatory interplay between protein domains is often crucial for enzymatic activity. It is not clear, however, how our knowledge could be extended to describe collective near-equilibrium motions of multidomain enzymes. We examined the effect of domain interactions on the low temperature near equilibrium dynamics of the native state, using phosphoglycerate kinase as model protein. We measured thermal activation of tryptophan phosphorescence quenching to explore millisecond-range protein motions. The two protein domains of phosphoglycerate kinase correspond to two dynamic units, but interdomain interactions link the motion of the two domains. The effect of the interdomain interactions on the activation of motions in the individual domains is asymmetric. As the temperature of the frozen protein is increased from the cryogenic, motions of the N domain are activated first. This is a partial activation, however, and the full dynamics of the domain becomes activated only after the activation of the C domain.
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16
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Arviv O, Levy Y. Folding of multidomain proteins: Biophysical consequences of tethering even in apparently independent folding. Proteins 2012; 80:2780-98. [DOI: 10.1002/prot.24161] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 07/11/2012] [Accepted: 07/16/2012] [Indexed: 01/09/2023]
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17
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Agócs G, Szabó BT, Köhler G, Osváth S. Comparing the folding and misfolding energy landscapes of phosphoglycerate kinase. Biophys J 2012; 102:2828-34. [PMID: 22735533 DOI: 10.1016/j.bpj.2012.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 04/27/2012] [Accepted: 05/01/2012] [Indexed: 11/30/2022] Open
Abstract
Partitioning of polypeptides between protein folding and amyloid formation is of outstanding pathophysiological importance. Using yeast phosphoglycerate kinase as model, here we identify the features of the energy landscape that decide the fate of the protein: folding or amyloidogenesis. Structure formation was initiated from the acid-unfolded state, and monitored by fluorescence from 10 ms to 20 days. Solvent conditions were gradually shifted between folding and amyloidogenesis, and the properties of the energy landscape governing structure formation were reconstructed. A gradual transition of the energy landscape between folding and amyloid formation was observed. In the early steps of both folding and misfolding, the protein searches through a hierarchically structured energy landscape to form a molten globule in a few seconds. Depending on the conditions, this intermediate either folds to the native state in a few minutes, or forms amyloid fibers in several days. As conditions are changed from folding to misfolding, the barrier separating the molten globule and native states increases, although the barrier to the amyloid does not change. In the meantime, the native state also becomes more unstable and the amyloid more stable. We conclude that the lower region of the energy landscape determines the final protein structure.
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Affiliation(s)
- Gergely Agócs
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
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18
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Dhar A, Girdhar K, Singh D, Gelman H, Ebbinghaus S, Gruebele M. Protein stability and folding kinetics in the nucleus and endoplasmic reticulum of eucaryotic cells. Biophys J 2011; 101:421-30. [PMID: 21767495 DOI: 10.1016/j.bpj.2011.05.071] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 05/21/2011] [Accepted: 05/24/2011] [Indexed: 11/29/2022] Open
Abstract
We measure the stability and folding relaxation rate of phosphoglycerate kinase (PGK) Förster resonance energy transfer (FRET) constructs localized in the nucleus or in the endoplasmic reticulum (ER) of eukaryotic cells. PGK has a more compact native state in the cellular compartments than in aqueous solution. Its native FRET signature is similar to that previously observed in a carbohydrate-crowding matrix, consistent with crowding being responsible for the compact native state of PGK in the cell. PGK folds through multiple states in vitro, but its folding kinetics is more two-state-like in the ER, so the folding mechanism can be modified by intracellular compartments. The nucleus increases PGK stability and folding rate over the cytoplasm and ER, even though the density of crowders in the nucleus is no greater than in the ER or cytoplasm. Nuclear folding kinetics (and to a lesser extent, thermodynamics) vary less from cell to cell than in the cytoplasm or ER, indicating a more homogeneous crowding and chemical environment in the nucleus.
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Affiliation(s)
- A Dhar
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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19
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Rosenkranz T, Schlesinger R, Gabba M, Fitter J. Native and Unfolded States of Phosphoglycerate Kinase Studied by Single‐Molecule FRET. Chemphyschem 2010; 12:704-10. [DOI: 10.1002/cphc.201000701] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/29/2010] [Indexed: 11/10/2022]
Affiliation(s)
- Tobias Rosenkranz
- Research Centre Jülich, ISB‐2: Molecular Biophysics, 52425 Jülich (Germany), Fax: (+49) 2461 61 1448
| | - Ramona Schlesinger
- Research Centre Jülich, ISB‐2: Molecular Biophysics, 52425 Jülich (Germany), Fax: (+49) 2461 61 1448
| | - Matteo Gabba
- Research Centre Jülich, ISB‐2: Molecular Biophysics, 52425 Jülich (Germany), Fax: (+49) 2461 61 1448
| | - Jörg Fitter
- Research Centre Jülich, ISB‐2: Molecular Biophysics, 52425 Jülich (Germany), Fax: (+49) 2461 61 1448
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20
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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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21
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Batey S, Nickson AA, Clarke J. Studying the folding of multidomain proteins. HFSP JOURNAL 2008; 2:365-77. [PMID: 19436439 DOI: 10.2976/1.2991513] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Indexed: 11/19/2022]
Abstract
There have been relatively few detailed comprehensive studies of the folding of protein domains (or modules) in the context of their natural covalently linked neighbors. This is despite the fact that a significant proportion of the proteome consists of multidomain proteins. In this review we highlight some key experimental investigations of the folding of multidomain proteins to draw attention to the difficulties that can arise in analyzing such systems. The evidence suggests that interdomain interactions can significantly affect stability, folding, and unfolding rates. However, preliminary studies suggest that folding pathways are unaffected-to this extent domains can be truly considered to be independent folding units. Nonetheless, it is clear that interactions between domains cannot be ignored, in particular when considering the effects of mutations.
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Affiliation(s)
- Sarah Batey
- Department of Chemistry, MRC Centre for Protein Engineering, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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22
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Predicting protein folding pathways at the mesoscopic level based on native interactions between secondary structure elements. BMC Bioinformatics 2008; 9:320. [PMID: 18651953 PMCID: PMC2527578 DOI: 10.1186/1471-2105-9-320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2008] [Accepted: 07/23/2008] [Indexed: 11/10/2022] Open
Abstract
Background Since experimental determination of protein folding pathways remains difficult, computational techniques are often used to simulate protein folding. Most current techniques to predict protein folding pathways are computationally intensive and are suitable only for small proteins. Results By assuming that the native structure of a protein is known and representing each intermediate conformation as a collection of fully folded structures in which each of them contains a set of interacting secondary structure elements, we show that it is possible to significantly reduce the conformation space while still being able to predict the most energetically favorable folding pathway of large proteins with hundreds of residues at the mesoscopic level, including the pig muscle phosphoglycerate kinase with 416 residues. The model is detailed enough to distinguish between different folding pathways of structurally very similar proteins, including the streptococcal protein G and the peptostreptococcal protein L. The model is also able to recognize the differences between the folding pathways of protein G and its two structurally similar variants NuG1 and NuG2, which are even harder to distinguish. We show that this strategy can produce accurate predictions on many other proteins with experimentally determined intermediate folding states. Conclusion Our technique is efficient enough to predict folding pathways for both large and small proteins at the mesoscopic level. Such a strategy is often the only feasible choice for large proteins. A software program implementing this strategy (SSFold) is available at .
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23
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Batey S, Clarke J. The folding pathway of a single domain in a multidomain protein is not affected by its neighbouring domain. J Mol Biol 2008; 378:297-301. [PMID: 18371978 PMCID: PMC2828540 DOI: 10.1016/j.jmb.2008.02.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 01/21/2008] [Accepted: 02/15/2008] [Indexed: 11/24/2022]
Abstract
Domains are the structural, functional, and evolutionary components of proteins. Most folding studies to date have concentrated on the folding of single domains, but more than 70% of human proteins contain more than one domain, and interdomain interactions can affect both the stability and the folding kinetics. Whether the folding pathway is altered by interdomain interactions is not yet known. Here we investigated the effect of a folded neighbouring domain on the folding pathway of spectrin R16 (the 16th α-helical repeat from chicken brain α-spectrin) by using the two-domain construct R1516. The R16 folds faster and unfolds more slowly in the presence of its folded neighbour R15 (the 15th α-helical repeat from chicken brain α-spectrin). An extensive Φ-value analysis of the R16 domain in R1516 was completed to compare the transition state of the R16 domain alone with that of the R16 domain in a multidomain construct. The results indicate that the folding pathways are the same. This result validates the current approach of breaking up larger proteins into domains for the study of protein folding pathways.
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24
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Mallam AL, Jackson SE. Use of protein engineering techniques to elucidate protein folding pathways. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2008; 84:57-113. [PMID: 19121700 DOI: 10.1016/s0079-6603(08)00403-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Anna L Mallam
- Department of Chemistry, Cambridge, CB2 1EW, United Kingdom
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25
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Strucksberg K, Rosenkranz T, Fitter J. Reversible and irreversible unfolding of multi-domain proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1591-603. [DOI: 10.1016/j.bbapap.2007.09.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 09/06/2007] [Accepted: 09/10/2007] [Indexed: 10/22/2022]
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26
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Randles LG, Batey S, Steward A, Clarke J. Distinguishing specific and nonspecific interdomain interactions in multidomain proteins. Biophys J 2007; 94:622-8. [PMID: 17890397 PMCID: PMC2157218 DOI: 10.1529/biophysj.107.119123] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multidomain proteins account for over two-thirds of the eukaryotic genome. Although there have been extensive studies into the biophysical properties of isolated domains, few have investigated how the domains interact. Spectrin is a well-characterized multidomain protein with domains linked in tandem array by contiguous helices. Several of these domains have been shown to be stabilized by their neighbors. Until now, this stabilization has been attributed to specific interactions between the natural neighbors, however we have recently observed that nonnatural neighboring domains can also induce a significant amount of stabilization. Here we investigate this nonnative stabilizing effect. We created spectrin-titin domain pairs of both spectrin R16 and R17 with a single titin I27 domain at either the N- or the C-terminus and found that spectrin domains are significantly stabilized, through slowed unfolding, by nonnative interactions at the C-terminus only. Of particular importance, we show that specific interactions between natural folded neighbors at either terminus confer even greater stability by additionally increasing the folding rate constants. We demonstrate that it is possible to distinguish between natural stabilizing interactions and nonspecific stabilizing effects through examination of the kinetics of well chosen mutant proteins. This work adds to the complexity of studying multidomain proteins.
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Affiliation(s)
- Lucy G Randles
- Cambridge University Chemical Laboratory, MRC Centre for Protein Engineering, Cambridge, United Kingdom
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27
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Young TA, Skordalakes E, Marqusee S. Comparison of Proteolytic Susceptibility in Phosphoglycerate Kinases from Yeast and E. coli: Modulation of Conformational Ensembles Without Altering Structure or Stability. J Mol Biol 2007; 368:1438-47. [PMID: 17397866 DOI: 10.1016/j.jmb.2007.02.077] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 02/15/2007] [Accepted: 02/22/2007] [Indexed: 11/21/2022]
Abstract
Escherichia coli phosphoglycerate kinase (PGK) is resistant to proteolytic cleavage while the yeast homolog from Saccharomyces cerevisiae is not. We have explored the biophysical basis of this surprising difference. The sequences of these homologs are 39% identical and 56% similar. Determination of the crystal structure for the E. coli protein and comparison to the previously solved yeast structure reveals that the two proteins have extremely similar tertiary structures, and their global stabilities determined by equilibrium denaturation are also very similar. The extrapolated unfolding rate of E. coli PGK is, however, 10(5) slower than that of the yeast homolog. This surprisingly large difference in unfolding rates appears to arise from a divergence in the extent of cooperativity between the two structural domains (the N and C-domains) that make up these kinases. This is supported by: (1) the C-domain of E. coli PGK cannot be expressed or fold independently of the N-domain, while both domains of the yeast protein fold in isolation into stable structures and (2) the energetics and kinetics of the proteolytically sensitive state of E. coli PGK match those for global unfolding. This suggests that proteolysis occurs from the globally unfolded state of E. coli PGK, while the characteristics defining the yeast homolog suggest that proteolysis occurs upon unfolding of only the C-domain, with the N-domain remaining folded and consequently resistant to cleavage.
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Affiliation(s)
- Tracy A Young
- Department of Molecular and Cell Biology and QB3 Institute, University of California, Berkeley, Berkeley, CA 94720-3206, USA
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28
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Han JH, Batey S, Nickson AA, Teichmann SA, Clarke J. The folding and evolution of multidomain proteins. Nat Rev Mol Cell Biol 2007; 8:319-30. [PMID: 17356578 DOI: 10.1038/nrm2144] [Citation(s) in RCA: 277] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Analyses of genomes show that more than 70% of eukaryotic proteins are composed of multiple domains. However, most studies of protein folding focus on individual domains and do not consider how interactions between domains might affect folding. Here, we address this by analysing the three-dimensional structures of multidomain proteins that have been characterized experimentally and observe that where the interface is small and loosely packed, or unstructured, the folding of the domains is independent. Furthermore, recent studies indicate that multidomain proteins have evolved mechanisms to minimize the problems of interdomain misfolding.
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Affiliation(s)
- Jung-Hoon Han
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK
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29
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Balog E, Laberge M, Fidy J. The influence of interdomain interactions on the intradomain motions in yeast phosphoglycerate kinase: a molecular dynamics study. Biophys J 2007; 92:1709-16. [PMID: 17158564 PMCID: PMC1796818 DOI: 10.1529/biophysj.106.093195] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 11/06/2006] [Indexed: 11/18/2022] Open
Abstract
A 3-ns molecular dynamics simulation in explicit solvent was performed to examine the inter- and intradomain motions of the two-domain enzyme yeast phosphoglycerate kinase without the presence of substrates. To elucidate contributions from individual domains, simulations were carried out on the complete enzyme as well as on each isolated domain. The enzyme is known to undergo a hinge-bending type of motion as it cycles from an open to a closed conformation to allow the phosphoryl transfer occur. Analysis of the correlation of atomic movements during the simulations confirms hinge bending in the nanosecond timescale: the two domains of the complete enzyme exhibit rigid body motions anticorrelated with respect to each other. The correlation of the intradomain motions of both domains converges, yielding a distinct correlation map in the enzyme. In the isolated domain simulations-in which interdomain interactions cannot occur-the correlation of domain motions no longer converges and shows a very small correlation during the same simulation time. This result points to the importance of interdomain contacts in the overall dynamics of the protein. The secondary structure elements responsible for interdomain contacts are also discussed.
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Affiliation(s)
- Erika Balog
- Department of Biophysics and Radiation Biology and Research Group for Membrane Biology of the Hungarian Academy of Sciences, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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30
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Batey S, Clarke J. Apparent cooperativity in the folding of multidomain proteins depends on the relative rates of folding of the constituent domains. Proc Natl Acad Sci U S A 2006; 103:18113-8. [PMID: 17108086 PMCID: PMC1636339 DOI: 10.1073/pnas.0604580103] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Approximately 75% of eukaryotic proteins contain more than one so-called independently folding domain. However, there have been relatively few systematic studies to investigate the effect of interdomain interactions on protein stability and fewer still on folding kinetics. We present the folding of pairs of three-helix bundle spectrin domains as a paradigm to indicate how complex such an analysis can be. Equilibrium studies show an increase in denaturant concentration required to unfold the domains with only a single unfolding transition; however, in some cases, this is not accompanied by the increase in m value, which would be expected if the protein is a truly cooperative, all-or-none system. We analyze the complex kinetics of spectrin domain pairs, both wild-type and carefully selected mutants. By comparing these pairs, we are able to demonstrate that equilibrium data alone are insufficient to describe the folding of multidomain proteins and to quantify the effects that one domain can have on its neighbor.
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Affiliation(s)
- Sarah Batey
- Department of Chemistry, University of Cambridge, Medical Research Council Centre for Protein Engineering, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Medical Research Council Centre for Protein Engineering, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- To whom correspondence should be addressed. E-mail:
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31
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Osváth S, Herényi L, Závodszky P, Fidy J, Köhler G. Hierarchic finite level energy landscape model: to describe the refolding kinetics of phosphoglycerate kinase. J Biol Chem 2006; 281:24375-80. [PMID: 16807241 DOI: 10.1074/jbc.m601915200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One of the most intriguing predictions of energy landscape models is the existence of non-exponential protein folding kinetics caused by hierarchical structures in the landscapes. Here we provide the strongest evidence so far of such hierarchy and determine the time constants and weights of the kinetic components of the suggested hierarchic energy landscape. To our knowledge, the idea of hierarchical folding energy barriers has never been tested over such a broad timescale. Refolding of yeast phosphoglycerate kinase was initiated from the guanidine-unfolded state by stopped-flow or manual mixing and monitored by tryptophan fluorescence from 1 ms to 15 min. The strategy to build a model that describes folding of yeast phosphoglycerate kinase was to start from the simplest paradigm and modify it stepwise to the necessary minimal extent after repeated comparisons with the experiments. We made no a priori assumptions about the folding landscape. The result was a hierarchic finite level landscape model that quantitatively describes the refolding of yeast phosphoglycerate kinase from 1 ms to 15 min. The early steps of the folding process happen in the upper region of the landscape, where the surface has a hierarchic structure. This leads to stretched kinetics in the early phase of the folding. The lower region of the energy landscape is dominated by a trap that reflects the accumulation of molten globule intermediate state. From this intermediate, the protein can reach the global energy minimum corresponding to the native state through a cross-barrier folding step.
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Affiliation(s)
- Szabolcs Osváth
- Department of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, H-1088 Budapest, Hungary.
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