1
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Singh A, Kundrotas PJ, Vakser IA. Diffusion of proteins in crowded solutions studied by docking-based modeling. J Chem Phys 2024; 161:095101. [PMID: 39225532 PMCID: PMC11374379 DOI: 10.1063/5.0220545] [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: 05/26/2024] [Accepted: 08/13/2024] [Indexed: 09/04/2024] Open
Abstract
The diffusion of proteins is significantly affected by macromolecular crowding. Molecular simulations accounting for protein interactions at atomic resolution are useful for characterizing the diffusion patterns in crowded environments. We present a comprehensive analysis of protein diffusion under different crowding conditions based on our recent docking-based approach simulating an intracellular crowded environment by sampling the intermolecular energy landscape using the Markov Chain Monte Carlo protocol. The procedure was extensively benchmarked, and the results are in very good agreement with the available experimental and theoretical data. The translational and rotational diffusion rates were determined for different types of proteins under crowding conditions in a broad range of concentrations. A protein system representing most abundant protein types in the E. coli cytoplasm was simulated, as well as large systems of other proteins of varying sizes in heterogeneous and self-crowding solutions. Dynamics of individual proteins was analyzed as a function of concentration and different diffusion rates in homogeneous and heterogeneous crowding. Smaller proteins diffused faster in heterogeneous crowding of larger molecules, compared to their diffusion in the self-crowded solution. Larger proteins displayed the opposite behavior, diffusing faster in the self-crowded solution. The results show the predictive power of our structure-based simulation approach for long timescales of cell-size systems at atomic resolution.
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Affiliation(s)
- Amar Singh
- Computational Biology Program, The University of Kansas, Lawrence, Kansas 66045, USA
| | - Petras J Kundrotas
- Computational Biology Program, The University of Kansas, Lawrence, Kansas 66045, USA
| | - Ilya A Vakser
- Computational Biology Program, The University of Kansas, Lawrence, Kansas 66045, USA
- Department of Molecular Biosciences, The University of Kansas, Lawrence, Kansas 66045, USA
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2
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Berner F, Kovermann M. Including the Ensemble of Unstructured Conformations in the Analysis of Protein's Native State by High-Pressure NMR Spectroscopy. Angew Chem Int Ed Engl 2024; 63:e202401343. [PMID: 38656763 DOI: 10.1002/anie.202401343] [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: 01/19/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024]
Abstract
The analysis of pressure induced changes in the chemical shift of proteins allows statements on structural fluctuations proteins exhibit at ambient pressure. The inherent issue of separating general pressure effects from structural related effects on the pressure dependence of chemical shifts has so far been addressed by considering the characteristics of random coil peptides on increasing pressure. In this work, chemically and pressure denatured states of the cold shock protein B from Bacillus subtilis (BsCspB) have been assigned in 2D 1H-15N HSQC NMR spectra and their dependence on increasing hydrostatic pressure has been evaluated. The pressure denatured polypeptide chain has been used to separate general from structural related effects on 1H and 15N chemical shifts of native BsCspB and the implications on the interpretation of pressure induced changes in the chemical shift regarding the structure of BsCspB are discussed. It has been found that the ensemble of unstructured conformations of BsCspB shows different responses to increasing pressure than random coil peptides do. Thus, the approach used for considering the general effects that arise when hydrostatic pressure increases changes the structural conclusions that are drawn from high pressure NMR spectroscopic experiments that rely on the analysis of chemical shifts.
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Affiliation(s)
- Frederic Berner
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78464, Konstanz, Germany
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78464, Konstanz, Germany
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3
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Grassmann G, Miotto M, Desantis F, Di Rienzo L, Tartaglia GG, Pastore A, Ruocco G, Monti M, Milanetti E. Computational Approaches to Predict Protein-Protein Interactions in Crowded Cellular Environments. Chem Rev 2024; 124:3932-3977. [PMID: 38535831 PMCID: PMC11009965 DOI: 10.1021/acs.chemrev.3c00550] [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: 07/31/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 04/11/2024]
Abstract
Investigating protein-protein interactions is crucial for understanding cellular biological processes because proteins often function within molecular complexes rather than in isolation. While experimental and computational methods have provided valuable insights into these interactions, they often overlook a critical factor: the crowded cellular environment. This environment significantly impacts protein behavior, including structural stability, diffusion, and ultimately the nature of binding. In this review, we discuss theoretical and computational approaches that allow the modeling of biological systems to guide and complement experiments and can thus significantly advance the investigation, and possibly the predictions, of protein-protein interactions in the crowded environment of cell cytoplasm. We explore topics such as statistical mechanics for lattice simulations, hydrodynamic interactions, diffusion processes in high-viscosity environments, and several methods based on molecular dynamics simulations. By synergistically leveraging methods from biophysics and computational biology, we review the state of the art of computational methods to study the impact of molecular crowding on protein-protein interactions and discuss its potential revolutionizing effects on the characterization of the human interactome.
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Affiliation(s)
- Greta Grassmann
- Department
of Biochemical Sciences “Alessandro Rossi Fanelli”, Sapienza University of Rome, Rome 00185, Italy
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Mattia Miotto
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Fausta Desantis
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- The
Open University Affiliated Research Centre at Istituto Italiano di
Tecnologia, Genoa 16163, Italy
| | - Lorenzo Di Rienzo
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Gian Gaetano Tartaglia
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
- Center
for Human Technologies, Genoa 16152, Italy
| | - Annalisa Pastore
- Experiment
Division, European Synchrotron Radiation
Facility, Grenoble 38043, France
| | - Giancarlo Ruocco
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
| | - Michele Monti
- RNA
System Biology Lab, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Edoardo Milanetti
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
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4
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Alfano C, Fichou Y, Huber K, Weiss M, Spruijt E, Ebbinghaus S, De Luca G, Morando MA, Vetri V, Temussi PA, Pastore A. Molecular Crowding: The History and Development of a Scientific Paradigm. Chem Rev 2024; 124:3186-3219. [PMID: 38466779 PMCID: PMC10979406 DOI: 10.1021/acs.chemrev.3c00615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/13/2024]
Abstract
It is now generally accepted that macromolecules do not act in isolation but "live" in a crowded environment, that is, an environment populated by numerous different molecules. The field of molecular crowding has its origins in the far 80s but became accepted only by the end of the 90s. In the present issue, we discuss various aspects that are influenced by crowding and need to consider its effects. This Review is meant as an introduction to the theme and an analysis of the evolution of the crowding concept through time from colloidal and polymer physics to a more biological perspective. We introduce themes that will be more thoroughly treated in other Reviews of the present issue. In our intentions, each Review may stand by itself, but the complete collection has the aspiration to provide different but complementary perspectives to propose a more holistic view of molecular crowding.
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Affiliation(s)
- Caterina Alfano
- Structural
Biology and Biophysics Unit, Fondazione
Ri.MED, 90100 Palermo, Italy
| | - Yann Fichou
- CNRS,
Bordeaux INP, CBMN UMR 5248, IECB, University
of Bordeaux, F-33600 Pessac, France
| | - Klaus Huber
- Department
of Chemistry, University of Paderborn, 33098 Paderborn, Germany
| | - Matthias Weiss
- Experimental
Physics I, Physics of Living Matter, University
of Bayreuth, 95440 Bayreuth, Germany
| | - Evan Spruijt
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Simon Ebbinghaus
- Lehrstuhl
für Biophysikalische Chemie and Research Center Chemical Sciences
and Sustainability, Research Alliance Ruhr, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Giuseppe De Luca
- Dipartimento
di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Valeria Vetri
- Dipartimento
di Fisica e Chimica − Emilio Segrè, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Annalisa Pastore
- King’s
College London, Denmark
Hill Campus, SE5 9RT London, United Kingdom
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5
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Kovermann M, Stefan A, Palazzetti C, Immler F, Dal Piaz F, Bernardi L, Cimone V, Bellone ML, Hochkoeppler A. The Mycobacterium tuberculosis protein tyrosine phosphatase MptpA features a pH dependent activity overlapping the bacterium sensitivity to acidic conditions. Biochimie 2023; 213:66-81. [PMID: 37201648 DOI: 10.1016/j.biochi.2023.04.014] [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: 02/09/2023] [Revised: 04/03/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023]
Abstract
The Mycobacterium tuberculosis low-molecular weight protein tyrosine phosphatase (MptpA) is responsible for the inhibition of phagosome-lysosome fusion and is essential for the bacterium pathogenicity. This inhibition implies that M. tuberculosis is not exposed to a strongly acidic environment in vivo, enabling successful propagation in host cells. Remarkably, MptpA has been previously structurally and functionally investigated, with special emphasis devoted to the enzyme properties at pH 8.0. Considering that the virulence of M. tuberculosis is strictly dependent on the avoidance of acidic conditions in vivo, we analysed the pH-dependence of the structural and catalytic properties of MptpA. Here we show that this enzyme undergoes pronounced conformational rearrangements when exposed to acidic pH conditions, inducing a severe decrease of the enzymatic catalytic efficiency at the expense of phosphotyrosine (pTyr). In particular, a mild decrease of pH from 6.5 to 6.0 triggers a significant increase of K0.5 of MptpA for phosphotyrosine, the phosphate group of which we determined to feature a pKa2 equal to 5.7. Surface plasmon resonance experiments confirmed that MptpA binds poorly to pTyr at pH values < 6.5. Notably, the effectiveness of the MptpA competitive inhibitor L335-M34 at pH 6 does largely outperform the inhibition exerted at neutral or alkaline pH values. Overall, our observations indicate a pronounced sensitivity of MptpA to acidic pH conditions, and suggest the search for competitive inhibitors bearing a negatively charged group featuring pKa values lower than that of the substrate phosphate group.
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Affiliation(s)
- Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätstraße 10, 78464, Konstanz, Germany
| | - Alessandra Stefan
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy; CSGI, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Firenze, Italy
| | - Chiara Palazzetti
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | - Fabian Immler
- Department of Chemistry, University of Konstanz, Universitätstraße 10, 78464, Konstanz, Germany
| | - Fabrizio Dal Piaz
- Department of Medicine, University of Salerno, Via Giovanni Paolo II 132, 84084, Fisciano, Italy
| | - Luca Bernardi
- Department of Industrial Chemistry "Toson Montanaro", University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | - Valentina Cimone
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy
| | - Maria Laura Bellone
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084, Fisciano, Italy
| | - Alejandro Hochkoeppler
- Department of Pharmacy and Biotechnology, University of Bologna, Viale Risorgimento 4, 40136, Bologna, Italy; CSGI, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Firenze, Italy.
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6
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Cho Y, Ryu H, Lim G, Nam S, Lee J. Improving Geometric Validation Metrics and Ensuring Consistency with Experimental Data through TrioSA: An NMR Refinement Protocol. Int J Mol Sci 2023; 24:13337. [PMID: 37686144 PMCID: PMC10487420 DOI: 10.3390/ijms241713337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/21/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
Protein model refinement a the crucial step in improving the quality of a predicted protein model. This study presents an NMR refinement protocol called TrioSA (torsion-angle and implicit-solvation-optimized simulated annealing) that improves the accuracy of backbone/side-chain conformations and the overall structural quality of proteins. TrioSA was applied to a subset of 3752 solution NMR protein structures accompanied by experimental NMR data: distance and dihedral angle restraints. We compared the initial NMR structures with the TrioSA-refined structures and found significant improvements in structural quality. In particular, we observed a reduction in both the maximum and number of NOE (nuclear Overhauser effect) violations, indicating better agreement with experimental NMR data. TrioSA improved geometric validation metrics of NMR protein structure, including backbone accuracy and the secondary structure ratio. We evaluated the contribution of each refinement element and found that the torsional angle potential played a significant role in improving the geometric validation metrics. In addition, we investigated protein-ligand docking to determine if TrioSA can improve biological outcomes. TrioSA structures exhibited better binding prediction compared to the initial NMR structures. This study suggests that further development and research in computational refinement methods could improve biomolecular NMR structural determination.
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Affiliation(s)
- Youngbeom Cho
- Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon 34141, Republic of Korea;
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea; (H.R.); (G.L.)
| | - Hyojung Ryu
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea; (H.R.); (G.L.)
| | - Gyutae Lim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea; (H.R.); (G.L.)
| | - Seungyoon Nam
- Department of Genome Medicine and Science, AI Convergence Center for Medical Science, Gachon Institute of Genome Medicine and Science, Gachon University Gil Medical Center, Gachon University College of Medicine, Incheon 21565, Republic of Korea
- Department of Health Sciences and Technology, Gachon Advanced Institute for Health Sciences and Technology, Gachon University, Incheon 21999, Republic of Korea
| | - Jinhyuk Lee
- Department of Bioinformatics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon 34141, Republic of Korea;
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea; (H.R.); (G.L.)
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7
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Irukuvajjula SS, Reddy JG, Vadrevu R. Crowding by Poly(ethylene glycol) Destabilizes Chemotaxis Protein Y (CheY). Biochemistry 2022; 61:1431-1443. [PMID: 35796609 DOI: 10.1021/acs.biochem.2c00030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The prevailing understanding of various aspects of biochemical processes, including folding, stability, intermolecular interactions, and the binding of metals, substrates, and inhibitors, is derived from studies carried out under dilute and homogeneous conditions devoid of a crowding-related environment. The effect of crowding-induced modulation on the structure and stability of native and magnesium-dependent Chemotaxis Y (CheY), a bacterial signaling protein, was probed in the presence and absence of poly(ethylene glycol) (PEG). A combined analysis from circular dichroism, intrinsic and extrinsic fluorescence, and tryptophan fluorescence lifetime changes indicates that PEG perturbs the structure but leaves the thermal stability largely unchanged. Intriguingly, while the stability of the protein is enhanced in the presence of magnesium under dilute buffer conditions, PEG-induced crowding leads to reduced thermal stability in the presence of magnesium. Nuclear magnetic resonance (NMR) chemical shift perturbations and resonance broadening for a subset of residues indicate that PEG interacts specifically with a subset of hydrophilic and hydrophobic residues found predominantly in α helices, β strands, and in the vicinity of the metal-binding region. Thus, PEG prompted conformational perturbation, presumably provides a different situation for magnesium interaction, thereby perturbing the magnesium-prompted stability. In summary, our results highlight the dominance of enthalpic contributions between PEG and CheY via both hydrophilic and hydrophobic interactions, which can subtly affect the conformation, modulating the metal-protein interaction and stability, implying that in the context of cellular situation, structure, stability, and magnesium binding thermodynamics of CheY may be different from those measured in dilute solution.
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Affiliation(s)
- Shivkumar Sharma Irukuvajjula
- Department of Biological Sciences, Birla Institute of Technology & Science─Pilani, Hyderabad Campus, Jawahar Nagar, Shamirpet, Hyderabad 500078, India
| | - Jithender G Reddy
- NMR Division, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Ministry of Science and Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Ramakrishna Vadrevu
- Department of Biological Sciences, Birla Institute of Technology & Science─Pilani, Hyderabad Campus, Jawahar Nagar, Shamirpet, Hyderabad 500078, India
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8
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Kistwal T, Mukhopadhyay A, Dasgupta S, Sharma KP, Datta A. Ultraslow Biological Water-Like Dynamics in Waterless Liquid Protein. J Phys Chem Lett 2022; 13:4389-4393. [PMID: 35548934 DOI: 10.1021/acs.jpclett.2c00702] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Fluorescence correlation spectroscopy and time-dependent fluorescence Stokes shift have been employed to elucidate dynamics in different time scales, ranging from picoseconds to nanoseconds, for human serum albumin, in its native and cationized forms as well as in the self-assembled complex of the cationized protein with the polymer surfactant (PS) glycolic acid ethoxylate lauryl ether. The effect of crowding in this complex, especially in the waterless condition, is of prime importance in this context. Excellent correlation of the dynamics with the structures, obtained by circular dichroism and Fourier transform infrared spectroscopy, has been observed. Slow solvation, associated classically with biological water, has been observed in these systems, even in the waterless condition. This apparently intriguing observation has been rationalized by the relaxation of segments of the protein and the PS in the microenvironment of the fluorescent probe.
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Affiliation(s)
- Tanuja Kistwal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Anasua Mukhopadhyay
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Souradip Dasgupta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Kamendra P Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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9
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Dreydoppel M, Balbach J, Weininger U. Monitoring protein unfolding transitions by NMR-spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2022; 76:3-15. [PMID: 34984658 PMCID: PMC9018662 DOI: 10.1007/s10858-021-00389-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/28/2021] [Indexed: 06/01/2023]
Abstract
NMR-spectroscopy has certain unique advantages for recording unfolding transitions of proteins compared e.g. to optical methods. It enables per-residue monitoring and separate detection of the folded and unfolded state as well as possible equilibrium intermediates. This allows a detailed view on the state and cooperativity of folding of the protein of interest and the correct interpretation of subsequent experiments. Here we summarize in detail practical and theoretical aspects of such experiments. Certain pitfalls can be avoided, and meaningful simplification can be made during the analysis. Especially a good understanding of the NMR exchange regime and relaxation properties of the system of interest is beneficial. We show by a global analysis of signals of the folded and unfolded state of GB1 how accurate values of unfolding can be extracted and what limits different NMR detection and unfolding methods. E.g. commonly used exchangeable amides can lead to a systematic under determination of the thermodynamic protein stability. We give several perspectives of how to deal with more complex proteins and how the knowledge about protein stability at residue resolution helps to understand protein properties under crowding conditions, during phase separation and under high pressure.
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Affiliation(s)
- Matthias Dreydoppel
- Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Jochen Balbach
- Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Ulrich Weininger
- Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, 06120, Halle (Saale), Germany.
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10
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Welte H, Sinn P, Kovermann M. Fluorine NMR Spectroscopy Enables to Quantify the Affinity Between DNA and Proteins in Cell Lysate. Chembiochem 2021; 22:2973-2980. [PMID: 34390111 PMCID: PMC8596521 DOI: 10.1002/cbic.202100304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/30/2021] [Indexed: 11/12/2022]
Abstract
The determination of the binding affinity quantifying the interaction between proteins and nucleic acids is of crucial interest in biological and chemical research. Here, we have made use of site-specific fluorine labeling of the cold shock protein from Bacillus subtilis, BsCspB, enabling to directly monitor the interaction with single stranded DNA molecules in cell lysate. High-resolution 19 F NMR spectroscopy has been applied to exclusively report on resonance signals arising from the protein under study. We have found that this experimental approach advances the reliable determination of the binding affinity between single stranded DNA molecules and its target protein in this complex biological environment by intertwining analyses based on NMR chemical shifts, signal heights, line shapes and simulations. We propose that the developed experimental platform offers a potent approach for the identification of binding affinities characterizing intermolecular interactions in native surroundings covering the nano-to-micromolar range that can be even expanded to in cell applications in future studies.
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Affiliation(s)
- Hannah Welte
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078467KonstanzGermany
| | - Pia Sinn
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078467KonstanzGermany
| | - Michael Kovermann
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078467KonstanzGermany
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11
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Köhn B, Schwarz P, Wittung-Stafshede P, Kovermann M. Impact of crowded environments on binding between protein and single-stranded DNA. Sci Rep 2021; 11:17682. [PMID: 34480058 PMCID: PMC8417293 DOI: 10.1038/s41598-021-97219-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/20/2021] [Indexed: 11/09/2022] Open
Abstract
The concept of Molecular Crowding depicts the high density of diverse molecules present in the cellular interior. Here, we determine the impact of low molecular weight and larger molecules on binding capacity of single-stranded DNA (ssDNA) to the cold shock protein B (CspB). Whereas structural features of ssDNA-bound CspB are fully conserved in crowded environments as probed by high-resolution NMR spectroscopy, intrinsic fluorescence quenching experiments reveal subtle changes in equilibrium affinity. Kinetic stopped-flow data showed that DNA-to-protein association is significantly retarded independent of choice of the molecule that is added to the solution, but dissociation depends in a nontrivial way on its size and chemical characteristics. Thus, for this DNA-protein interaction, excluded volume effect does not play the dominant role but instead observed effects are dictated by the chemical properties of the crowder. We propose that surrounding molecules are capable of specific modification of the protein's hydration shell via soft interactions that, in turn, tune protein-ligand binding dynamics and affinity.
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Affiliation(s)
- Birgit Köhn
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology KoRS-CB, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Patricia Schwarz
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Pernilla Wittung-Stafshede
- Department of Biology and Biological Engineering, Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - Michael Kovermann
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany. .,Konstanz Research School Chemical Biology KoRS-CB, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
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12
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Zhao X, Meng X, Ragauskas AJ, Lai C, Ling Z, Huang C, Yong Q. Unlocking the secret of lignin-enzyme interactions: Recent advances in developing state-of-the-art analytical techniques. Biotechnol Adv 2021; 54:107830. [PMID: 34480987 DOI: 10.1016/j.biotechadv.2021.107830] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/07/2021] [Accepted: 08/29/2021] [Indexed: 02/08/2023]
Abstract
Bioconversion of renewable lignocellulosics to produce liquid fuels and chemicals is one of the most effective ways to solve the problem of fossil resource shortage, energy security, and environmental challenges. Among the many biorefinery pathways, hydrolysis of lignocellulosics to fermentable monosaccharides by cellulase is arguably the most critical step of lignocellulose bioconversion. In the process of enzymatic hydrolysis, the direct physical contact between enzymes and cellulose is an essential prerequisite for the hydrolysis to occur. However, lignin is considered one of the most recalcitrant factors hindering the accessibility of cellulose by binding to cellulase unproductively, which reduces the saccharification rate and yield of sugars. This results in high costs for the saccharification of carbohydrates. The various interactions between enzymes and lignin have been explored from different perspectives in literature, and a basic lignin inhibition mechanism has been proposed. However, the exact interaction between lignin and enzyme as well as the recently reported promotion of some types of lignin on enzymatic hydrolysis is still unclear at the molecular level. Multiple analytical techniques have been developed, and fully unlocking the secret of lignin-enzyme interactions would require a continuous improvement of the currently available analytical techniques. This review summarizes the current commonly used advanced research analytical techniques for investigating the interaction between lignin and enzyme, including quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy (FLS), and molecular dynamics (MD) simulations. Interdisciplinary integration of these analytical methods is pursued to provide new insight into the interactions between lignin and enzymes. This review will serve as a resource for future research seeking to develop new methodologies for a better understanding of the basic mechanism of lignin-enzyme binding during the critical hydrolysis process.
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Affiliation(s)
- Xiaoxue Zhao
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Center for Renewable Carbon, Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996, USA; Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chenhuan Lai
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Zhe Ling
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Caoxing Huang
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Qiang Yong
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
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