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Wehrhan L, Keller BG. Fluorinated Protein-Ligand Complexes: A Computational Perspective. J Phys Chem B 2024. [PMID: 38886167 DOI: 10.1021/acs.jpcb.4c01493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Fluorine is an element renowned for its unique properties. Its powerful capability to modulate molecular properties makes it an attractive substituent for protein binding ligands; however, the rational design of fluorination can be challenging with effects on interactions and binding energies being difficult to predict. In this Perspective, we highlight how computational methods help us to understand the role of fluorine in protein-ligand binding with a focus on molecular simulation. We underline the importance of an accurate force field, present fluoride channels as a showcase for biomolecular interactions with fluorine, and discuss fluorine specific interactions like the ability to form hydrogen bonds and interactions with aryl groups. We put special emphasis on the disruption of water networks and entropic effects.
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Affiliation(s)
- Leon Wehrhan
- Department of Chemistry, Biology and Pharmacy, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Bettina G Keller
- Department of Chemistry, Biology and Pharmacy, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
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2
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Mukherjee S, Ramos S, Pezzotti S, Kalarikkal A, Prass TM, Galazzo L, Gendreizig D, Barbosa N, Bordignon E, Havenith M, Schäfer LV. Entropy Tug-of-War Determines Solvent Effects in the Liquid-Liquid Phase Separation of a Globular Protein. J Phys Chem Lett 2024; 15:4047-4055. [PMID: 38580324 PMCID: PMC11033941 DOI: 10.1021/acs.jpclett.3c03421] [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] [Received: 12/06/2023] [Revised: 02/15/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
Liquid-liquid phase separation (LLPS) plays a key role in the compartmentalization of cells via the formation of biomolecular condensates. Here, we combined atomistic molecular dynamics (MD) simulations and terahertz (THz) spectroscopy to determine the solvent entropy contribution to the formation of condensates of the human eye lens protein γD-Crystallin. The MD simulations reveal an entropy tug-of-war between water molecules that are released from the protein droplets and those that are retained within the condensates, two categories of water molecules that were also assigned spectroscopically. A recently developed THz-calorimetry method enables quantitative comparison of the experimental and computational entropy changes of the released water molecules. The strong correlation mutually validates the two approaches and opens the way to a detailed atomic-level understanding of the different driving forces underlying the LLPS.
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Affiliation(s)
- Saumyak Mukherjee
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Sashary Ramos
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Simone Pezzotti
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Abhishek Kalarikkal
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Tobias M. Prass
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Laura Galazzo
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Dominik Gendreizig
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Natercia Barbosa
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Enrica Bordignon
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Martina Havenith
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Lars V. Schäfer
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
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3
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Kalathingal M, Rhee YM. Thermodynamic consequences of stapling side-chains on a peptide ligand using a lactam-bridge: A theoretical study on anti-angiogenic peptides targeting VEGF. Proteins 2024. [PMID: 38602129 DOI: 10.1002/prot.26692] [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: 01/19/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
Peptides are promising therapeutic agents for various biological targets due to their high efficacy and low toxicity, and the design of peptide ligands with high binding affinity to the target of interest is of utmost importance in peptide-based drug design. Introducing a conformational constraint to a flexible peptide ligand using a side-chain lactam-bridge is a convenient and efficient method to improve its binding affinity to the target. However, in general, such a small structural modification to a flexible ligand made with the intent of lowering the configurational entropic penalty for binding may have unintended consequences in different components of the binding enthalpy and entropy, including the configurational entropy component, which are still not clearly understood. Toward probing this, we examine different components of the binding enthalpy and entropy as well as the underlying structure and dynamics, for a side-chain lactam-bridged peptide inhibitor and its flexible analog forming complexes with vascular endothelial growth factor (VEGF), using all-atom molecular dynamics simulations. It is found that introducing a side-chain lactam-bridge constraint into the flexible peptide analog led to a gain in configurational entropy change but losses in solvation entropy, solute internal energy, and solvation energy changes upon binding, pinpointing the opportunities and challenges in drug design. The present study features an interplay between configurational and solvation entropy changes, as well as the one between binding enthalpy and entropy, in ligand-target binding upon imposing a conformational constraint into a flexible ligand.
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Affiliation(s)
- Mahroof Kalathingal
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
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4
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Gilson MK, Kurtzman T. Free Energy Density of a Fluid and Its Role in Solvation and Binding. J Chem Theory Comput 2024; 20:2871-2887. [PMID: 38536144 DOI: 10.1021/acs.jctc.3c01173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The concept that a fluid has a position-dependent free energy density appears in the literature but has not been fully developed or accepted. We set this concept on an unambiguous theoretical footing via the following strategy. First, we set forth four desiderata that should be satisfied by any definition of the position-dependent free energy density, f(R), in a system comprising only a fluid and a rigid solute: its volume integral, plus the fixed internal energy of the solute, should be the system free energy; it deviates from its bulk value, fbulk, near a solute but should asymptotically approach fbulk with increasing distance from the solute; it should go to zero where the solvent density goes to zero; and it should be well-defined in the most general case of a fluid made up of flexible molecules with an arbitrary interaction potential. Second, we use statistical thermodynamics to formulate a definition of the free energy density that satisfies these desiderata. Third, we show how any free energy density satisfying the desiderata may be used to analyze molecular processes in solution. In particular, because the spatial integral of f(R) equals the free energy of the system, it can be used to compute free energy changes that result from the rearrangement of solutes as well as the forces exerted on the solutes by the solvent. This enables the use of a thermodynamic analysis of water in protein binding sites to inform ligand design. Finally, we discuss related literature and address published concerns regarding the thermodynamic plausibility of a position-dependent free energy density. The theory presented here has applications in theoretical and computational chemistry and may be further generalizable beyond fluids, such as to solids and macromolecules.
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Affiliation(s)
- Michael K Gilson
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Department of Chemistry and Biochemistry, UC San Diego, La Jolla, California 92093, United States
| | - Tom Kurtzman
- PhD Programs in Chemistry, Biochemistry, and Biology, The Graduate Center of the City University of New York, New York, New York 10016, United States
- Department of Chemistry, Lehman College, The City University of New York, Bronx, New York 10468, United States
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5
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Mukherjee S, Schäfer LV. Thermodynamic forces from protein and water govern condensate formation of an intrinsically disordered protein domain. Nat Commun 2023; 14:5892. [PMID: 37735186 PMCID: PMC10514047 DOI: 10.1038/s41467-023-41586-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) can drive a multitude of cellular processes by compartmentalizing biological cells via the formation of dense liquid biomolecular condensates, which can function as membraneless organelles. Despite its importance, the molecular-level understanding of the underlying thermodynamics of this process remains incomplete. In this study, we use atomistic molecular dynamics simulations of the low complexity domain (LCD) of human fused in sarcoma (FUS) protein to investigate the contributions of water and protein molecules to the free energy changes that govern LLPS. Both protein and water components are found to have comparably sizeable thermodynamic contributions to the formation of FUS condensates. Moreover, we quantify the counteracting effects of water molecules that are released into the bulk upon condensate formation and the waters retained within the protein droplets. Among the various factors considered, solvation entropy and protein interaction enthalpy are identified as the most important contributions, while solvation enthalpy and protein entropy changes are smaller. These results provide detailed molecular insights on the intricate thermodynamic interplay between protein- and solvation-related forces underlying the formation of biomolecular condensates.
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Affiliation(s)
- Saumyak Mukherjee
- Center for Theoretical Chemistry, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Lars V Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, D-44780, Bochum, Germany.
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6
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Barros EP, Ries B, Champion C, Rieder SR, Riniker S. Accounting for Solvation Correlation Effects on the Thermodynamics of Water Networks in Protein Cavities. J Chem Inf Model 2023; 63:1794-1805. [PMID: 36917685 PMCID: PMC10052353 DOI: 10.1021/acs.jcim.2c01610] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
Macromolecular recognition and ligand binding are at the core of biological function and drug discovery efforts. Water molecules play a significant role in mediating the protein-ligand interaction, acting as more than just the surrounding medium by affecting the thermodynamics and thus the outcome of the binding process. As individual water contributions are impossible to measure experimentally, a range of computational methods have emerged to identify hydration sites in protein pockets and characterize their energetic contributions for drug discovery applications. Even though several methods model solvation effects explicitly, they focus on determining the stability of specific water sites independently and neglect solvation correlation effects upon replacement of clusters of water molecules, which typically happens in hit-to-lead optimization. In this work, we rigorously determine the conjoint effects of replacing all combinations of water molecules in protein binding pockets through the use of the RE-EDS multistate free-energy method, which combines Hamiltonian replica exchange (RE) and enveloping distribution sampling (EDS). Applications on the small bovine pancreatic trypsin inhibitor and four proteins of the bromodomain family illustrate the extent of solvation correlation effects on water thermodynamics, with the favorability of replacement of the water sites by pharmacophore probes highly dependent on the composition of the water network and the pocket environment. Given the ubiquity of water networks in biologically relevant protein targets, we believe our approach can be helpful for computer-aided drug discovery by providing a pocket-specific and a priori systematic consideration of solvation effects on ligand binding and selectivity.
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Affiliation(s)
- Emilia P Barros
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Benjamin Ries
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Candide Champion
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Salomé R Rieder
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Sereina Riniker
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
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7
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Kalayan J, Chakravorty A, Warwicker J, Henchman RH. Total free energy analysis of fully hydrated proteins. Proteins 2023; 91:74-90. [PMID: 35964252 PMCID: PMC10087023 DOI: 10.1002/prot.26411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 12/15/2022]
Abstract
The total free energy of a hydrated biomolecule and its corresponding decomposition of energy and entropy provides detailed information about regions of thermodynamic stability or instability. The free energies of four hydrated globular proteins with different net charges are calculated from a molecular dynamics simulation, with the energy coming from the system Hamiltonian and entropy using multiscale cell correlation. Water is found to be most stable around anionic residues, intermediate around cationic and polar residues, and least stable near hydrophobic residues, especially when more buried, with stability displaying moderate entropy-enthalpy compensation. Conversely, anionic residues in the proteins are energetically destabilized relative to singly solvated amino acids, while trends for other residues are less clear-cut. Almost all residues lose intraresidue entropy when in the protein, enthalpy changes are negative on average but may be positive or negative, and the resulting overall stability is moderate for some proteins and negligible for others. The free energy of water around single amino acids is found to closely match existing hydrophobicity scales. Regarding the effect of secondary structure, water is slightly more stable around loops, of intermediate stability around β strands and turns, and least stable around helices. An interesting asymmetry observed is that cationic residues stabilize a residue when bonded to its N-terminal side but destabilize it when on the C-terminal side, with a weaker reversed trend for anionic residues.
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Affiliation(s)
- Jas Kalayan
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Arghya Chakravorty
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | - Jim Warwicker
- Manchester Institute of Biotechnology and School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Richard H Henchman
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
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Arora H, Dhiman D, Kumar K, Venkatesu P. Fortification of thermal and structural stability of hemoglobin using choline chloride-based deep eutectic solvents. Phys Chem Chem Phys 2022; 24:29683-29692. [PMID: 36453254 DOI: 10.1039/d2cp03407g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Of late, DESs have occupied the centre stage due to their eco-friendly and resource-efficient nature and their low toxicity. In this work, we have investigated the structural and thermal stability of hemoglobin (Hb) in two choline chloride ([Ch]Cl)-based DESs namely urea [Ch]Cl-urea (DES1) and [Ch]Cl-glycerol (Gly); (DES 2). Different biophysical techniques reveal that the presence of DESs facilitates the stability of Hb in a concentration-dependent manner and the extent of stability is more pronounced in [Ch]Cl-Gly as compared to [Ch]Cl-urea. Additionally, for a better understanding of the role of DESs in modulating the thermal and structural stability of Hb, studies have been performed on Hb in the presence of individual constituents of DESs, i.e., [Ch]Cl, urea, and Gly. Altogether, it was observed that the effect on the stability of Hb was by the presence of the DESs rather than their individual constituents. For instance, urea itself is a destabilizing co-solvent for biomolecules. However, the harmful effects of urea were surpassed when a DES is formed in the presence of [Ch]Cl. Therefore, overall, it can be concluded that both DESs can be described as potential non-harmful, green, and promising solvents for enhancing the structural and thermal stability of Hb.
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Affiliation(s)
- Harshita Arora
- Department of Chemistry, University of Delhi, Delhi, 110 007, India.
| | - Diksha Dhiman
- Department of Chemistry, University of Delhi, Delhi, 110 007, India.
| | - Krishan Kumar
- Department of Chemistry, University of Delhi, Delhi, 110 007, India. .,Department of Biological Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Pannuru Venkatesu
- Department of Chemistry, University of Delhi, Delhi, 110 007, India.
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9
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From structure and dynamics to biomolecular functions: The ubiquitous role of solvent in biology. Curr Opin Struct Biol 2022; 77:102462. [PMID: 36150344 DOI: 10.1016/j.sbi.2022.102462] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 08/22/2022] [Indexed: 12/14/2022]
Abstract
Biological activity requires a solvent that can provide a suitable environment, which satisfies the twin need for stability and the ability to change. Among all the solvents water plays the most important role. We review, analyze, and comment on recent works on the structure and dynamics of water around biomolecules and their role in specific biological functions. While studies in the past have focused on understanding the biomolecule-water interactions through a hydration layer; recently the attention has shifted towards understanding functions at a molecular level. Such a microscopic understanding clearly requires elucidation of detailed dynamical processes where solvent molecules play an important role. Finally, we comment on the advances made in understanding the role of water inside a biological cell.
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10
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Kruchinin SE, Kislinskaya EE, Chuev GN, Fedotova MV. Protein 3D Hydration: A Case of Bovine Pancreatic Trypsin Inhibitor. Int J Mol Sci 2022; 23:ijms232314785. [PMID: 36499117 PMCID: PMC9737982 DOI: 10.3390/ijms232314785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/20/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Characterization of the hydrated state of a protein is crucial for understanding its structural stability and function. In the present study, we have investigated the 3D hydration structure of the protein BPTI (bovine pancreatic trypsin inhibitor) by molecular dynamics (MD) and the integral equation method in the three-dimensional reference interaction site model (3D-RISM) approach. Both methods have found a well-defined hydration layer around the protein and revealed the localization of BPTI buried water molecules corresponding to the X-ray crystallography data. Moreover, under 3D-RISM calculations, the obtained positions of waters bound firmly to the BPTI sites are in reasonable agreement with the experimental results mentioned above for the BPTI crystal form. The analysis of the 3D hydration structure (thickness of hydration shell and hydration numbers) was performed for the entire protein and its polar and non-polar parts using various cut-off distances taken from the literature as well as by a straightforward procedure proposed here for determining the thickness of the hydration layer. Using the thickness of the hydration shell from this procedure allows for calculating the total hydration number of biomolecules properly under both methods. Following this approach, we have obtained the thickness of the BPTI hydration layer of 3.6 Å with 369 water molecules in the case of MD simulation and 3.9 Å with 333 water molecules in the case of the 3D-RISM approach. The above procedure was also applied for a more detailed description of the BPTI hydration structure near the polar charged and uncharged radicals as well as non-polar radicals. The results presented for the BPTI as an example bring new knowledge to the understanding of protein hydration.
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Affiliation(s)
- Sergey E. Kruchinin
- G.A. Krestov Institute of Solution Chemistry, The Russian Academy of Sciences, Akademicheskaya St., 1, 153045 Ivanovo, Russia
| | - Ekaterina E. Kislinskaya
- Department of Fundamental and Applied Chemistry, Institute of Mathematics, Information Technology and Science, Ivanovo State University, Ermak St., 39, 153025 Ivanovo, Russia
| | - Gennady N. Chuev
- Institute of Theoretical and Experimental Biophysics, The Russian Academy of Sciences, Institutskaya St., Pushchino, 142290 Moscow, Russia
- Correspondence: (G.N.C.); (M.V.F.)
| | - Marina V. Fedotova
- G.A. Krestov Institute of Solution Chemistry, The Russian Academy of Sciences, Akademicheskaya St., 1, 153045 Ivanovo, Russia
- Correspondence: (G.N.C.); (M.V.F.)
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Conformational Stability and Denaturation Processes of Proteins Investigated by Electrophoresis under Extreme Conditions. Molecules 2022; 27:molecules27206861. [PMID: 36296453 PMCID: PMC9610776 DOI: 10.3390/molecules27206861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/10/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
The functional structure of proteins results from marginally stable folded conformations. Reversible unfolding, irreversible denaturation, and deterioration can be caused by chemical and physical agents due to changes in the physicochemical conditions of pH, ionic strength, temperature, pressure, and electric field or due to the presence of a cosolvent that perturbs the delicate balance between stabilizing and destabilizing interactions and eventually induces chemical modifications. For most proteins, denaturation is a complex process involving transient intermediates in several reversible and eventually irreversible steps. Knowledge of protein stability and denaturation processes is mandatory for the development of enzymes as industrial catalysts, biopharmaceuticals, analytical and medical bioreagents, and safe industrial food. Electrophoresis techniques operating under extreme conditions are convenient tools for analyzing unfolding transitions, trapping transient intermediates, and gaining insight into the mechanisms of denaturation processes. Moreover, quantitative analysis of electrophoretic mobility transition curves allows the estimation of the conformational stability of proteins. These approaches include polyacrylamide gel electrophoresis and capillary zone electrophoresis under cold, heat, and hydrostatic pressure and in the presence of non-ionic denaturing agents or stabilizers such as polyols and heavy water. Lastly, after exposure to extremes of physical conditions, electrophoresis under standard conditions provides information on irreversible processes, slow conformational drifts, and slow renaturation processes. The impressive developments of enzyme technology with multiple applications in fine chemistry, biopharmaceutics, and nanomedicine prompted us to revisit the potentialities of these electrophoretic approaches. This feature review is illustrated with published and unpublished results obtained by the authors on cholinesterases and paraoxonase, two physiologically and toxicologically important enzymes.
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