1
|
Oney-Hawthorne SD, Barondeau DP. Fe-S cluster biosynthesis and maturation: Mass spectrometry-based methods advancing the field. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119784. [PMID: 38908802 DOI: 10.1016/j.bbamcr.2024.119784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/25/2024] [Accepted: 06/10/2024] [Indexed: 06/24/2024]
Abstract
Iron‑sulfur (FeS) clusters are inorganic protein cofactors that perform essential functions in many physiological processes. Spectroscopic techniques have historically been used to elucidate details of FeS cluster type, their assembly and transfer, and changes in redox and ligand binding properties. Structural probes of protein topology, complex formation, and conformational dynamics are also necessary to fully understand these FeS protein systems. Recent developments in mass spectrometry (MS) instrumentation and methods provide new tools to investigate FeS cluster and structural properties. With the unique advantage of sampling all species in a mixture, MS-based methods can be utilized as a powerful complementary approach to probe native dynamic heterogeneity, interrogate protein folding and unfolding equilibria, and provide extensive insight into protein binding partners within an entire proteome. Here, we highlight key advances in FeS protein studies made possible by MS methodology and contribute an outlook for its role in the field.
Collapse
Affiliation(s)
| | - David P Barondeau
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA.
| |
Collapse
|
2
|
Dornbusch D, Hanke M, Tomm E, Kielar C, Grundmeier G, Keller A, Fahmy K. Cold denaturation of DNA origami nanostructures. Chem Commun (Camb) 2024; 60:5590-5593. [PMID: 38666465 DOI: 10.1039/d3cc05985e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2024]
Abstract
The coupling of structural transitions to heat capacity changes leads to destabilization of macromolecules at both elevated and lowered temperatures. DNA origami not only exhibit this property but also provide a nanoscopic observable of cold denaturation processes by directing intramolecular strain to the most sensitive elements within their hierarchical architecture.
Collapse
Affiliation(s)
- Daniel Dornbusch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, Dresden 01328, Germany.
- Technische Universität Dresden, BIOTEC, Cluster of Excellence Physics of Life, Dresden 01062, Germany
| | - Marcel Hanke
- Paderborn University, Technical and Macromolecular Chemistry, Warburger Str. 100, Paderborn 33098, Germany.
| | - Emilia Tomm
- Paderborn University, Technical and Macromolecular Chemistry, Warburger Str. 100, Paderborn 33098, Germany.
| | - Charlotte Kielar
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, Dresden 01328, Germany.
- Helmholtz-Zentrum Dresden-Rossendorf, Institute for Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, Dresden 01328, Germany
| | - Guido Grundmeier
- Paderborn University, Technical and Macromolecular Chemistry, Warburger Str. 100, Paderborn 33098, Germany.
| | - Adrian Keller
- Paderborn University, Technical and Macromolecular Chemistry, Warburger Str. 100, Paderborn 33098, Germany.
| | - Karim Fahmy
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, Dresden 01328, Germany.
- Technische Universität Dresden, BIOTEC, Cluster of Excellence Physics of Life, Dresden 01062, Germany
| |
Collapse
|
3
|
Borzova VA, Eronina TB, Mikhaylova VV, Roman SG, Chernikov AM, Chebotareva NA. Effect of Chemical Chaperones on the Stability of Proteins during Heat- or Freeze-Thaw Stress. Int J Mol Sci 2023; 24:10298. [PMID: 37373447 DOI: 10.3390/ijms241210298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
The importance of studying the structural stability of proteins is determined by the structure-function relationship. Protein stability is influenced by many factors among which are freeze-thaw and thermal stresses. The effect of trehalose, betaine, sorbitol and 2-hydroxypropyl-β-cyclodextrin (HPCD) on the stability and aggregation of bovine liver glutamate dehydrogenase (GDH) upon heating at 50 °C or freeze-thawing was studied by dynamic light scattering, differential scanning calorimetry, analytical ultracentrifugation and circular dichroism spectroscopy. A freeze-thaw cycle resulted in the complete loss of the secondary and tertiary structure, and aggregation of GDH. All the cosolutes suppressed freeze-thaw- and heat-induced aggregation of GDH and increased the protein thermal stability. The effective concentrations of the cosolutes during freeze-thawing were lower than during heating. Sorbitol exhibited the highest anti-aggregation activity under freeze-thaw stress, whereas the most effective agents stabilizing the tertiary structure of GDH were HPCD and betaine. HPCD and trehalose were the most effective agents suppressing GDH thermal aggregation. All the chemical chaperones stabilized various soluble oligomeric forms of GDH against both types of stress. The data on GDH were compared with the effects of the same cosolutes on glycogen phosphorylase b during thermal and freeze-thaw-induced aggregation. This research can find further application in biotechnology and pharmaceutics.
Collapse
Affiliation(s)
- Vera A Borzova
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| | - Tatiana B Eronina
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| | - Valeriya V Mikhaylova
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| | - Svetlana G Roman
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| | - Andrey M Chernikov
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| | - Natalia A Chebotareva
- Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia
| |
Collapse
|
4
|
Tomalty HE, Graham LA, Walker VK, Davies PL. Chilling injury in human kidney tubule cells after subzero storage is not mitigated by antifreeze protein addition. Cryobiology 2023:S0011-2240(23)00034-2. [PMID: 37164251 DOI: 10.1016/j.cryobiol.2023.05.002] [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: 12/02/2022] [Revised: 03/26/2023] [Accepted: 05/06/2023] [Indexed: 05/12/2023]
Abstract
By preventing freezing, antifreeze proteins (AFPs) can permit cells and organs to be stored at subzero temperatures. As metabolic rates decrease with decreasing temperature, subzero static cold storage (SZ-SCS) could provide more time for tissue matching and potentially lead to fewer discarded organs. Human kidneys are generally stored for under 24 h and the tubule epithelium is known to be particularly sensitive to static cold storage (SCS). Here, telomerase-immortalized proximal-tubule epithelial cells from humans, which closely resemble their progenitors, were used as a proxy to assess the potential benefit of SZ-SCS for kidneys. The effects of hyperactive AFPs from a beetle and Cryostasis Storage Solution were compared to University of Wisconsin Solution at standard SCS temperatures (4 °C) and at -6 °C for up to six days. Although the AFPs helped guard against freezing, lower storage temperatures under these conditions were not beneficial. Compared to cells at 4 °C, those stored at -6 °C showed decreased viability as well as increased lactate dehydrogenase release and apoptosis. This suggests that this kidney cell type might be prone to chilling injury and that the addition of AFPs to enable SZ-SCS may not be effective for increasing storage times.
Collapse
Affiliation(s)
- Heather E Tomalty
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
| | - Laurie A Graham
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
| | - Virginia K Walker
- Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
| |
Collapse
|
5
|
Ó'Fágáin C, Colliton K. Storage and Lyophilization of Pure Proteins. Methods Mol Biol 2023; 2699:421-475. [PMID: 37647008 DOI: 10.1007/978-1-0716-3362-5_19] [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] [Indexed: 09/01/2023]
Abstract
This chapter outlines empirical procedures for the storage of pure proteins with preservation of high levels of biological activity. It describes simple and workable means of preventing microbial contamination and proteolytic degradation and the use of various types of stabilizing additives. It sets out the principles of lyophilization (a complex process comprising freezing, primary drying, and secondary drying stages, otherwise known as freeze-drying). There follows a general procedure for the use of lyophilizer apparatus with emphasis on best practice and on pitfalls to avoid. The use of modulated differential scanning calorimetry to measure the glass transition temperature, a key parameter in the design and successful operation of lyophilization processes, is described. This chapter concludes with brief summaries of interesting recent work in the field.
Collapse
Affiliation(s)
- Ciarán Ó'Fágáin
- School of Biotechnology, Dublin City University, Dublin, Ireland.
| | - Keith Colliton
- Pfizer Ireland Pharmaceuticals, Grange Castle Business Park, Dublin, Ireland
| |
Collapse
|
6
|
Lin CW, Oney-Hawthorne SD, Kuo ST, Barondeau DP, Russell DH. Mechanistic Insights into IscU Conformation Regulation for Fe-S Cluster Biogenesis Revealed by Variable Temperature Electrospray Ionization Native Ion Mobility Mass Spectrometry. Biochemistry 2022; 61:2733-2741. [PMID: 36351081 PMCID: PMC10009881 DOI: 10.1021/acs.biochem.2c00429] [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: 11/10/2022]
Abstract
Iron-sulfur (Fe-S) cluster (ISC) cofactors are required for the function of many critical cellular processes. In the ISC Fe-S cluster biosynthetic pathway, IscU assembles Fe-S cluster intermediates from iron, electrons, and inorganic sulfur, which is provided by the cysteine desulfurase enzyme IscS. IscU also binds to Zn, which mimics and competes for binding with the Fe-S cluster. Crystallographic and nuclear magnetic resonance spectroscopic studies reveal that IscU is a metamorphic protein that exists in multiple conformational states, which include at least a structured form and a disordered form. The structured form of IscU is favored by metal binding and is stable in a narrow temperature range, undergoing both cold and hot denaturation. Interestingly, the form of IscU that binds IscS and functions in Fe-S cluster assembly remains controversial. Here, results from variable temperature electrospray ionization (vT-ESI) native ion mobility mass spectrometry (nIM-MS) establish that IscU exists in structured, intermediate, and disordered forms that rearrange to more extended conformations at higher temperatures. A comparison of Zn-IscU and apo-IscU reveals that Zn(II) binding attenuates the cold/heat denaturation of IscU, promotes refolding of IscU, favors the structured and intermediate conformations, and inhibits the disordered high charge states. Overall, these findings provide a structural rationalization for the role of Zn(II) in stabilizing IscU conformations and IscS in altering the IscU active site to prepare for Zn(II) release and cluster synthesis. This work highlights how vT-ESI-nIM-MS can be applied as a powerful tool in mechanistic enzymology by providing details of relationships among temperature, protein conformations, and ligand/protein binding.
Collapse
Affiliation(s)
- Cheng-Wei Lin
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - Shelby D Oney-Hawthorne
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - Syuan-Ting Kuo
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - David P Barondeau
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A & M University, College Station, Texas 77843, United States
| |
Collapse
|
7
|
Norgate EL, Upton R, Hansen K, Bellina B, Brookes C, Politis A, Barran PE. Cold Denaturation of Proteins in the Absence of Solvent: Implications for Protein Storage. Angew Chem Int Ed Engl 2022; 61:e202115047. [PMID: 35313047 PMCID: PMC9325448 DOI: 10.1002/anie.202115047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Indexed: 12/12/2022]
Abstract
The effect of temperature on the stability of proteins is well explored above 298 K, but harder to track experimentally below 273 K. Variable-temperature ion mobility mass spectrometry (VT IM-MS) allows us to measure the structure of molecules at sub-ambient temperatures. Here we monitor conformational changes that occur to two isotypes of monoclonal antibodies (mAbs) on cooling by measuring their collision cross sections (CCS) at discrete drift gas temperatures from 295 to 160 K. The CCS at 250 K is larger than predicted from collisional theory and experimental data at 295 K. This restructure is attributed to change in the strength of stabilizing intermolecular interactions. Below 250 K the CCS of the mAbs increases in line with prediction implying no rearrangement. Comparing data from isotypes suggest disulfide bridging influences thermal structural rearrangement. These findings indicate that in vacuo deep-freezing minimizes denaturation and maintains the native fold and VT IM-MS measurements at sub ambient temperatures provide new insights to the phenomenon of cold denaturation.
Collapse
Affiliation(s)
- Emma L Norgate
- Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - Rosie Upton
- Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - Kjetil Hansen
- Department of Chemistry, King's College London, 7 Trinity Street, London, SE1 1DB, UK
| | - Bruno Bellina
- Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| | - C Brookes
- Bristol-Myers Squibb, Moreton, Wirral, CH46 1QW, UK
| | - Argyris Politis
- Department of Chemistry, King's College London, 7 Trinity Street, London, SE1 1DB, UK
| | - Perdita E Barran
- Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester, M1 7DN, UK
| |
Collapse
|
8
|
Norgate EL, Upton R, Hansen K, Bellina B, Brookes C, Politis A, Barran PE. Cold Denaturation of Proteins in the Absence of Solvent: Implications for Protein Storage. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 134:e202115047. [PMID: 38505418 PMCID: PMC10947158 DOI: 10.1002/ange.202115047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Indexed: 11/07/2022]
Abstract
The effect of temperature on the stability of proteins is well explored above 298 K, but harder to track experimentally below 273 K. Variable-temperature ion mobility mass spectrometry (VT IM-MS) allows us to measure the structure of molecules at sub-ambient temperatures. Here we monitor conformational changes that occur to two isotypes of monoclonal antibodies (mAbs) on cooling by measuring their collision cross sections (CCS) at discrete drift gas temperatures from 295 to 160 K. The CCS at 250 K is larger than predicted from collisional theory and experimental data at 295 K. This restructure is attributed to change in the strength of stabilizing intermolecular interactions. Below 250 K the CCS of the mAbs increases in line with prediction implying no rearrangement. Comparing data from isotypes suggest disulfide bridging influences thermal structural rearrangement. These findings indicate that in vacuo deep-freezing minimizes denaturation and maintains the native fold and VT IM-MS measurements at sub ambient temperatures provide new insights to the phenomenon of cold denaturation.
Collapse
Affiliation(s)
- Emma L. Norgate
- Manchester Institute of BiotechnologyUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - Rosie Upton
- Manchester Institute of BiotechnologyUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - Kjetil Hansen
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Bruno Bellina
- Manchester Institute of BiotechnologyUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - C. Brookes
- Bristol-Myers SquibbMoretonWirralCH46 1QWUK
| | - Argyris Politis
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Perdita E. Barran
- Manchester Institute of BiotechnologyUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| |
Collapse
|
9
|
Tejaswi Naidu K, Prakash Prabhu N. An able-cryoprotectant and a moderate denaturant: distinctive character of ethylene glycol on protein stability. J Biomol Struct Dyn 2022; 40:820-832. [DOI: 10.1080/07391102.2020.1819422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- K. Tejaswi Naidu
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - N. Prakash Prabhu
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| |
Collapse
|
10
|
Parui S, Jana B. Cold denaturation induced helix-to-helix transition and its implication to activity of helical antifreeze protein. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
11
|
Zhou T, Yao Y, Zhang Q, Mezzenga R. Cryogenic activity and stability of benzaldehyde lyase enzyme in lipidic mesophases-nanoconfined water. Chem Commun (Camb) 2021; 57:5650-5653. [PMID: 33972973 DOI: 10.1039/d1cc01315g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Phytantriol-based lipidic mesophases (LMs) are introduced as a platform for cryoenzymology, which relies on the presence of liquid water in LMs at subzero temperatures. After incorporation into LMs, the model enzyme Benzaldehyde lyase (BAL) shows high cryogenic stability and activity. In contrast, BAL in bulk solution undergoes significant secondary structural transitions caused by low temperatures (cold denaturation), demonstrating the potential of this approach to enable in meso cryoenzymology.
Collapse
Affiliation(s)
- Tao Zhou
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zurich, Switzerland.
| | - Yang Yao
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zurich, Switzerland.
| | - Qin Zhang
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zurich, Switzerland. and Institut des Sciences et Ingénierie Chimiques, EPFL, 1015 Lausanne, Switzerland
| | - Raffaele Mezzenga
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zurich, Switzerland. and Department of Materials, ETH Zurich, 8093 Zürich, Switzerland
| |
Collapse
|
12
|
Hung CL, Kuo YH, Lee SW, Chiang YW. Protein Stability Depends Critically on the Surface Hydrogen-Bonding Network: A Case Study of Bid Protein. J Phys Chem B 2021; 125:8373-8382. [PMID: 34314184 DOI: 10.1021/acs.jpcb.1c03245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding how proteins retain structural stability is not only of fundamental importance in biophysics but also critical to industrial production of antibodies and vaccines. Protein stability is known to depend mainly on two effects: internal hydrophobicity and H-bonding between the protein surface and solvent. A challenging task is to identify their individual contributions to a protein. Here, we investigate the structural stability of the apoptotic Bid protein in solutions containing various concentrations of guanidinium hydrochloride and urea using a combination of recently developed methods including the QTY (glutamine, threonine, and tyrosine) code and electron spin resonance-based peak-height analysis. We show that when the internal hydrophobicity of Bid is broken down using the QTY code, the surface H-bonding alone is sufficient to retain the structural stability intact. When the surface H-bonding is disrupted, Bid becomes sensitive to the temperature-dependent internal hydrophobicity such that it exhibits a reversible cold unfolding above water's freezing point. Using the combined approach, we show that the free-energy contributions of the two effects can be more reliably obtained. The surface H bonds are more important than the other effect in determining the structural stability of Bid protein.
Collapse
Affiliation(s)
- Chien-Lun Hung
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Hsuan Kuo
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Su Wei Lee
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| |
Collapse
|
13
|
Arsiccio A, McCarty J, Pisano R, Shea JE. Heightened Cold-Denaturation of Proteins at the Ice–Water Interface. J Am Chem Soc 2020; 142:5722-5730. [DOI: 10.1021/jacs.9b13454] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Andrea Arsiccio
- Department of Applied Science and Technology, Politecnico di Torino, 24 corso Duca degli Abruzzi, Torino 10129, Italy
| | - James McCarty
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225, United States
| | - Roberto Pisano
- Department of Applied Science and Technology, Politecnico di Torino, 24 corso Duca degli Abruzzi, Torino 10129, Italy
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Department of Physics, University of California, Santa Barbara, California 93106, United States
| |
Collapse
|
14
|
Pastore A, Martin SR, Temussi PA. Generalized View of Protein Folding: In Medio Stat Virtus. J Am Chem Soc 2019; 141:2194-2200. [PMID: 30566837 DOI: 10.1021/jacs.8b10779] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Proteins are often described in textbooks as being only "marginally stable" but many proteins, specifically those with a high free energy of unfolding are, in fact, so stable that they exist only in the fully folded state except under harsh denaturing conditions. Proteins that are truly only marginally stable, those with a low free energy of unfolding, exist as an equilibrium mixture of folded and unfolded forms under "normal" conditions. To some extent such proteins have some features in common with "intrinsically disordered" proteins. We analyzed the relationship between these marginally stable proteins and intrinsically disordered proteins in order to fully understand the twilight zone that distinguishes the two ensembles in the hope of clarifying the fuzzy borders of the current classification that divides the protein world into folded and intrinsically disordered ones. Our analysis suggests that the division may be too drastic and misleading, because it puts within the same category proteins with very different behaviors. We propose a restricted, albeit operational, definition of "marginally stable proteins", referring by this term only to proteins whose free energy difference between the folded and unfolded states falls in the interval 0-3 kcal/mol. These proteins have special features because they normally exist as equilibrium mixtures of folded and unfolded species or as molten globule states. This coexistence makes marginally stable proteins ideal tools to study even small environmental changes to which they may behave as natural sensors.
Collapse
Affiliation(s)
- Annalisa Pastore
- The Wohl Institute, King's College London , 5 Cutcombe Road , London SE59RT , United Kingdom.,Department of Molecular Medicine , University of Pavia , Pavia 27100 , Italy
| | - Stephen R Martin
- Structural Biology Science Technology Platform, The Francis Crick Institute , 1 Midland Road , London NW1 1AT , United Kingdom
| | - Piero Andrea Temussi
- The Wohl Institute, King's College London , 5 Cutcombe Road , London SE59RT , United Kingdom.,Dipartimento di Scienze Chimiche , Universita' di Napoli Federico II , Napoli 80126 , Italy
| |
Collapse
|