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Villavicencio B, Ligabue-Braun R, Verli H. Structural Characteristics of Glycocins: Unraveling the Role of S-Linked Carbohydrates and Other Structural Elements. J Chem Inf Model 2022; 62:927-935. [PMID: 35129982 DOI: 10.1021/acs.jcim.1c01001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycocins are antimicrobial peptides with glycosylations, often an S-linked monosaccharide. Their recent structure elucidation has brought forth questions about their mechanisms of action as well as the impact of S-glycosylation on their structural behavior. Here, we investigated structural characteristics of glycocins using a computational approach. Depending on the peptide's class (sublancin- or glycocin F-like), the sugar changes the peptide's flexibility. Also, the presence of glycosylation is necessary for the lack of structure of Asm1. The C-terminal tail in glycocin F-like peptides influenced their structured regions, acting like a regulator. These findings corroborate the versatility of these post-translational modifications, pointing toward their potential use in molecular engineering.
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Affiliation(s)
- Bianca Villavicencio
- Graduate Program in Cellular and Molecular Biology (PPGBCM-UFRGS), Center for Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, Brazil
| | - Rodrigo Ligabue-Braun
- Department of Pharmacosciences, Graduate Program in Biosciences (PPGBio-UFCSPA), Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre CEP 90050-170, Brazil
| | - Hugo Verli
- Department of Molecular Biology and Biotechnology, Graduate Program in Cellular and Molecular Biology (PPGBCM-UFRGS), Center for Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre CEP 91501-970, Brazil
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2
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Sakhrani VV, Ghosh RK, Hilario E, Weiss KL, Coates L, Mueller LJ. Toho-1 β-lactamase: backbone chemical shift assignments and changes in dynamics upon binding with avibactam. JOURNAL OF BIOMOLECULAR NMR 2021; 75:303-318. [PMID: 34218390 PMCID: PMC9122098 DOI: 10.1007/s10858-021-00375-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Backbone chemical shift assignments for the Toho-1 β-lactamase (263 amino acids, 28.9 kDa) are reported based on triple resonance solution-state NMR experiments performed on a uniformly 2H,13C,15N-labeled sample. These assignments allow for subsequent site-specific characterization at the chemical, structural, and dynamical levels. At the chemical level, titration with the non-β-lactam β-lactamase inhibitor avibactam is found to give chemical shift perturbations indicative of tight covalent binding that allow for mapping of the inhibitor binding site. At the structural level, protein secondary structure is predicted based on the backbone chemical shifts and protein residue sequence using TALOS-N and found to agree well with structural characterization from X-ray crystallography. At the dynamical level, model-free analysis of 15N relaxation data at a single field of 16.4 T reveals well-ordered structures for the ligand-free and avibactam-bound enzymes with generalized order parameters of ~ 0.85. Complementary relaxation dispersion experiments indicate that there is an escalation in motions on the millisecond timescale in the vicinity of the active site upon substrate binding. The combination of high rigidity on short timescales and active site flexibility on longer timescales is consistent with hypotheses for achieving both high catalytic efficiency and broad substrate specificity: the induced active site dynamics allows variously sized substrates to be accommodated and increases the probability that the optimal conformation for catalysis will be sampled.
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Affiliation(s)
- Varun V Sakhrani
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Rittik K Ghosh
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Eduardo Hilario
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Kevin L Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA
| | - Leighton Coates
- Second Target Station, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA.
| | - Leonard J Mueller
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA.
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3
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Bhakat S. Pepsin-like aspartic proteases (PAPs) as model systems for combining biomolecular simulation with biophysical experiments. RSC Adv 2021; 11:11026-11047. [PMID: 35423571 PMCID: PMC8695779 DOI: 10.1039/d0ra10359d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/21/2021] [Indexed: 01/26/2023] Open
Abstract
Pepsin-like aspartic proteases (PAPs) are a class of aspartic proteases which shares tremendous structural similarity with human pepsin. One of the key structural features of PAPs is the presence of a β-hairpin motif otherwise known as flap. The biological function of the PAPs is highly dependent on the conformational dynamics of the flap region. In apo PAPs, the conformational dynamics of the flap is dominated by the rotational degrees of freedom associated with χ1 and χ2 angles of conserved Tyr (or Phe in some cases). However it is plausible that dihedral order parameters associated with several other residues might play crucial roles in the conformational dynamics of apo PAPs. Due to their size, complexities associated with conformational dynamics and clinical significance (drug targets for malaria, Alzheimer's disease etc.), PAPs provide a challenging testing ground for computational and experimental methods focusing on understanding conformational dynamics and molecular recognition in biomolecules. The opening of the flap region is necessary to accommodate substrate/ligand in the active site of the PAPs. The BIG challenge is to gain atomistic details into how reversible ligand binding/unbinding (molecular recognition) affects the conformational dynamics. Recent reports of kinetics (K i, K d) and thermodynamic parameters (ΔH, TΔS, and ΔG) associated with macro-cyclic ligands bound to BACE1 (belongs to PAP family) provide a perfect challenge (how to deal with big ligands with multiple torsional angles and select optimum order parameters to study reversible ligand binding/unbinding) for computational methods to predict binding free energies and kinetics beyond typical test systems e.g. benzamide-trypsin. In this work, i reviewed several order parameters which were proposed to capture the conformational dynamics and molecular recognition in PAPs. I further highlighted how machine learning methods can be used as order parameters in the context of PAPs. I then proposed some open ideas and challenges in the context of molecular simulation and put forward my case on how biophysical experiments e.g. NMR, time-resolved FRET etc. can be used in conjunction with biomolecular simulation to gain complete atomistic insights into the conformational dynamics of PAPs.
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Affiliation(s)
- Soumendranath Bhakat
- Division of Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University P. O. Box 124 SE-22100 Lund Sweden +46-769608418
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Cárdenas R, Martínez-Seoane J, Amero C. Combining Experimental Data and Computational Methods for the Non-Computer Specialist. Molecules 2020; 25:E4783. [PMID: 33081072 PMCID: PMC7594097 DOI: 10.3390/molecules25204783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 01/01/2023] Open
Abstract
Experimental methods are indispensable for the study of the function of biological macromolecules, not just as static structures, but as dynamic systems that change conformation, bind partners, perform reactions, and respond to different stimulus. However, providing a detailed structural interpretation of the results is often a very challenging task. While experimental and computational methods are often considered as two different and separate approaches, the power and utility of combining both is undeniable. The integration of the experimental data with computational techniques can assist and enrich the interpretation, providing new detailed molecular understanding of the systems. Here, we briefly describe the basic principles of how experimental data can be combined with computational methods to obtain insights into the molecular mechanism and expand the interpretation through the generation of detailed models.
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Affiliation(s)
| | | | - Carlos Amero
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico; (R.C.); (J.M.-S.)
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5
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Sakhrani VV, Hilario E, Caulkins BG, Hatcher-Skeers ME, Fan L, Dunn MF, Mueller LJ. Backbone assignments and conformational dynamics in the S. typhimurium tryptophan synthase α-subunit from solution-state NMR. JOURNAL OF BIOMOLECULAR NMR 2020; 74:341-354. [PMID: 32415580 PMCID: PMC7451264 DOI: 10.1007/s10858-020-00320-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Backbone assignments for the isolated α-subunit of Salmonella typhimurium tryptophan synthase (TS) are reported based on triple resonance solution-state NMR experiments on a uniformly 2H,13C,15N-labeled sample. From the backbone chemical shifts, secondary structure and random coil index order parameters (RCI-S2) are predicted. Titration with the 3-indole-D-glycerol 3'-phosphate analog, N-(4'-trifluoromethoxybenzenesulfonyl)-2-aminoethyl phosphate (F9), leads to chemical shift perturbations indicative of conformational changes from which an estimate of the dissociation constant is obtained. Comparisons of the backbone chemical-shifts, RCI-S2 values, and site-specific relaxation times with and without F9 reveal allosteric changes including modulation in secondary structures and loop rigidity induced upon ligand binding. A comparison is made to the X-ray crystal structure of the α-subunit in the full TS αββα bi-enzyme complex and to two new X-ray crystal structures of the isolated TS α-subunit reported in this work.
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Affiliation(s)
- Varun V Sakhrani
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Eduardo Hilario
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Bethany G Caulkins
- Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Mary E Hatcher-Skeers
- Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Li Fan
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Michael F Dunn
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Leonard J Mueller
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA.
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Lozano-Aponte J, Scior T, Ambrosio FNM, González-Melchor M, Alexander C. Exploring electrostatic patterns of human, murine, equine and canine TLR4/MD-2 receptors. Innate Immun 2019; 26:364-380. [PMID: 31874581 PMCID: PMC7903528 DOI: 10.1177/1753425919894628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Electrostatic interactions between phosphate anions and Toll-like receptor 4 / Myeloid differentiation factor-2 (TLR4/MD-2) protein complexes of human, murine, equine and canine species were computed. Such knowledge can provide mechanistic information about recognising LPS-like ligands, since anionic phosphate groups belong to the structural features of LPS with their diphosphorylated diglucosamine backbone. Sequence composition analyses, electrostatic interaction potentials and docked energies as well as molecular dynamics studies evaluated the phosphate interactions within the triangular LPS binding site (wedge). According to electrostatic analyses, human, horse and dog wedges possess phosphate-binding sites with indistinct positive and negative charge distributions, but the murine wedge shows a unique strong negative net charge at the site where antagonists bind in other species (Pan). Docking of a phosphate mono-anion (probe) confirmed its repulsion at this Pan site, but the Pag site of the murine wedge attracted the probe. It is occupied by phosphate groups of agonists in other species (Pag). Molecular dynamics trajectories show a variable degree of random walk across the wedges, that is, not following electrostatic preferences (neither Pag nor Pan). In summary, two opposing electrostatic patterns exist -murine versus human, equine and canine species - all of which reflect the potential dual activity mode of under-acylated ligands such as lipid IVA.
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Affiliation(s)
- Jorge Lozano-Aponte
- Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Campus Puebla, Mexico
| | - Thomas Scior
- Departamento de Farmacia, Benemérita Universidad Autónoma de Puebla, Mexico
| | | | | | - Christian Alexander
- Division of Cellular Microbiology, Research Center Borstel- Leibniz Lung Center, Germany
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Maya-Martinez R, French-Pacheco L, Valdés-García G, Pastor N, Amero C. Different Dynamics in 6aJL2 Proteins Associated with AL Amyloidosis, a Conformational Disease. Int J Mol Sci 2019; 20:E4078. [PMID: 31438515 PMCID: PMC6747610 DOI: 10.3390/ijms20174078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/16/2019] [Accepted: 05/22/2019] [Indexed: 12/12/2022] Open
Abstract
Light-chain amyloidosis (AL) is the most common systemic amyloidosis and is caused by the deposition of mainly insoluble immunoglobulin light chain amyloid fibrils in multiple organs, causing organ failure and eventually death. The germ-line λ6a has been implicated in AL, where a single point mutant at amino acid 24 (6aJL2-R24G) has been observed in around 25% of patient samples. Structural analysis has shown only subtle differences between both proteins; nevertheless, 6aJL2-R24G is more prone to form amyloid fibrils. To improve our understanding of the role of protein flexibility in amyloid fibril formation, we have used a combination of solution nuclear magnetic resonance spectroscopy and molecular dynamics simulations to complement the structural insight with dynamic knowledge. Fast timescale dynamics (ps-ns) were equivalent for both proteins, but suggested exchange events for some residues. Even though most of the intermediate dynamics (μs-ms) occurred at a similar region for both proteins, the specific characteristics are very different. A minor population detected in the dispersion experiments could be associated with the formation of an off-pathway intermediate that protects from fiber formation more efficiently in the germ-line protein. Moreover, we found that the hydrogen bond patterns for both proteins are similar, but the lifetime for the mutant is significantly reduced; as a consequence, there is a decrease in the stability of the tertiary structure that extends throughout the protein and leads to an increase in the propensity to form amyloid fibers.
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Affiliation(s)
- Roberto Maya-Martinez
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Leidys French-Pacheco
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Gilberto Valdés-García
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Nina Pastor
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Carlos Amero
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico.
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Abstract
Eukaryotic protein kinases (PKs) are a large family of proteins critical for cellular response to external signals, acting as molecular switches. PKs propagate biochemical signals by catalyzing phosphorylation of other proteins, including other PKs, which can undergo conformational changes upon phosphorylation and catalyze further phosphorylations. Although PKs have been studied thoroughly across the domains of life, the structures of these proteins are sparsely understood in numerous groups of organisms, including plants. In addition to efforts towards determining crystal structures of PKs, research on human PKs has incorporated molecular dynamics (MD) simulations to study the conformational dynamics underlying the switching of PK function. This approach of experimental structural biology coupled with computational biophysics has led to improved understanding of how PKs become catalytically active and why mutations cause pathological PK behavior, at spatial and temporal resolutions inaccessible to current experimental methods alone. In this review, we argue for the value of applying MD simulation to plant PKs. We review the basics of MD simulation methodology, the successes achieved through MD simulation in animal PKs, and current work on plant PKs using MD simulation. We conclude with a discussion of the future of MD simulations and plant PKs, arguing for the importance of molecular simulation in the future of plant PK research.
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Narayanan C, Bafna K, Roux LD, Agarwal PK, Doucet N. Applications of NMR and computational methodologies to study protein dynamics. Arch Biochem Biophys 2017; 628:71-80. [PMID: 28483383 DOI: 10.1016/j.abb.2017.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 02/07/2023]
Abstract
Overwhelming evidence now illustrates the defining role of atomic-scale protein flexibility in biological events such as allostery, cell signaling, and enzyme catalysis. Over the years, spin relaxation nuclear magnetic resonance (NMR) has provided significant insights on the structural motions occurring on multiple time frames over the course of a protein life span. The present review article aims to illustrate to the broader community how this technique continues to shape many areas of protein science and engineering, in addition to being an indispensable tool for studying atomic-scale motions and functional characterization. Continuing developments in underlying NMR technology alongside software and hardware developments for complementary computational approaches now enable methodologies to routinely provide spatial directionality and structural representations traditionally harder to achieve solely using NMR spectroscopy. In addition to its well-established role in structural elucidation, we present recent examples that illustrate the combined power of selective isotope labeling, relaxation dispersion experiments, chemical shift analyses, and computational approaches for the characterization of conformational sub-states in proteins and enzymes.
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Affiliation(s)
- Chitra Narayanan
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada
| | - Khushboo Bafna
- Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Louise D Roux
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada
| | - Pratul K Agarwal
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA; Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37830, USA
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boul. des Prairies, Laval, QC H7V 1B7, Canada; PROTEO, The Quebec Network for Research on Protein Function, Structure, and Engineering, 1045 Avenue de la Médecine, Université Laval, Québec, QC G1V 0A6, Canada; GRASP, The Groupe de Recherche Axé sur la Structure des Protéines, 3649 Promenade Sir William Osler, McGill University, Montréal, QC H3G 0B1, Canada.
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Using Small Angle X-Ray Scattering (SAXS) to Characterize the Solution Conformation and Flexibility of Matrix Metalloproteinases (MMPs). Methods Mol Biol 2017. [PMID: 28299734 DOI: 10.1007/978-1-4939-6863-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Small angle X-ray scattering (SAXS) provides information about the conformation and flexibility of proteins in solution, and hence provides complementary structural information to that obtained from X-ray crystallography and nuclear magnetic resonance spectroscopy. In this chapter, we describe the methods for the preparation of matrix metalloproteinase (MMP) samples for SAXS analyses, and for the acquisition, processing and interpretation of the SAXS data.
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Abstract
It is now common knowledge that enzymes are mobile entities relying on complex atomic-scale dynamics and coordinated conformational events for proper ligand recognition and catalysis. However, the exact role of protein dynamics in enzyme function remains either poorly understood or difficult to interpret. This mini-review intends to reconcile biophysical observations and biological significance by first describing a number of common experimental and computational methodologies employed to characterize atomic-scale residue motions on various timescales in enzymes, and second by illustrating how the knowledge of these motions can be used to describe the functional behavior of enzymes and even act upon it. Two biologically relevant examples will be highlighted, namely the HIV-1 protease and DNA polymerase β enzyme systems.
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Abstract
Nuclear magnetic resonance (NMR) spectroscopy provides a unique toolbox of experimental probes for studying dynamic processes on a wide range of timescales, ranging from picoseconds to milliseconds and beyond. Along with NMR hardware developments, recent methodological advancements have enabled the characterization of allosteric proteins at unprecedented detail, revealing intriguing aspects of allosteric mechanisms and increasing the proportion of the conformational ensemble that can be observed by experiment. Here, we present an overview of NMR spectroscopic methods for characterizing equilibrium fluctuations in free and bound states of allosteric proteins that have been most influential in the field. By combining NMR experimental approaches with molecular simulations, atomistic-level descriptions of the mechanisms by which allosteric phenomena take place are now within reach.
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Affiliation(s)
- Sarina Grutsch
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Sven Brüschweiler
- Department of Computational & Structural Biology, Max F. Perutz Laboratories, Campus Vienna Biocenter 5, Vienna, Austria
| | - Martin Tollinger
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
- * E-mail:
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