1
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Unke OT, Stöhr M, Ganscha S, Unterthiner T, Maennel H, Kashubin S, Ahlin D, Gastegger M, Medrano Sandonas L, Berryman JT, Tkatchenko A, Müller KR. Biomolecular dynamics with machine-learned quantum-mechanical force fields trained on diverse chemical fragments. SCIENCE ADVANCES 2024; 10:eadn4397. [PMID: 38579003 DOI: 10.1126/sciadv.adn4397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 02/29/2024] [Indexed: 04/07/2024]
Abstract
The GEMS method enables molecular dynamics simulations of large heterogeneous systems at ab initio quality.
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Affiliation(s)
- Oliver T Unke
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
- Machine Learning Group, Technische Universität Berlin, 10587 Berlin, Germany
- DFG Cluster of Excellence "Unifying Systems in Catalysis" (UniSysCat), Technische Universität Berlin, 10623 Berlin, Germany
| | - Martin Stöhr
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg City, Luxembourg
| | - Stefan Ganscha
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
| | - Thomas Unterthiner
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
| | - Hartmut Maennel
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
| | - Sergii Kashubin
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
| | - Daniel Ahlin
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
| | - Michael Gastegger
- Machine Learning Group, Technische Universität Berlin, 10587 Berlin, Germany
- DFG Cluster of Excellence "Unifying Systems in Catalysis" (UniSysCat), Technische Universität Berlin, 10623 Berlin, Germany
- BASLEARN - TU Berlin/BASF Joint Lab for Machine Learning, Technische Universität Berlin, 10587 Berlin, Germany
| | - Leonardo Medrano Sandonas
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg City, Luxembourg
| | - Joshua T Berryman
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg City, Luxembourg
| | - Alexandre Tkatchenko
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg City, Luxembourg
| | - Klaus-Robert Müller
- Google DeepMind, Tucholskystraße 2, 10117 Berlin, Germany and Brandschenkestrasse 110, 8002 Zürich, Switzerland
- Machine Learning Group, Technische Universität Berlin, 10587 Berlin, Germany
- Department of Artificial Intelligence, Korea University, Anam-dong, Seongbuk-gu, Seoul 02841, Korea
- Max Planck Institute for Informatics, Stuhlsatzenhausweg, 66123 Saarbrücken, Germany
- BIFOLD - Berlin Institute for the Foundations of Learning and Data, Berlin, Germany
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2
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Greenspan NS. Epitopes, paratopes, and other topes 30 years on: Understanding what we are talking about. Hum Immunol 2023; 84:429-438. [PMID: 37407356 DOI: 10.1016/j.humimm.2023.06.006] [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: 05/02/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023]
Abstract
The question of which protein antigens, such as HLA class I or class II molecules, will bind, and how well, to a given antibody is often assumed to depend exclusively on the details of protein surface structure. These structures are usually based on static models resulting from X-ray crystallography. While these notions are useful, the ultimate causal factors determining how well a given antigen binds a given antibody are based in thermodynamics and can include atomic mobility and the time-varying conformations of proteins. In this article, fundamental biophysical principles of antibody-antigen interaction are discussed, concepts critical for a deeper understanding of the pertinent molecular phenomena are highlighted, and common misunderstandings are identified and debunked.
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Affiliation(s)
- Neil S Greenspan
- Department of Pathology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, United States.
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3
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Abstract
Multivalent proteins and nucleic acids, collectively referred to as multivalent associative biomacromolecules, provide the driving forces for the formation and compositional regulation of biomolecular condensates. Here, we review the key concepts of phase transitions of aqueous solutions of associative biomacromolecules, specifically proteins that include folded domains and intrinsically disordered regions. The phase transitions of these systems come under the rubric of coupled associative and segregative transitions. The concepts underlying these processes are presented, and their relevance to biomolecular condensates is discussed.
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Affiliation(s)
- Rohit V Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Samuel R Cohen
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Furqan Dar
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
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4
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Zhao G, Zhu H. Cation-π Interactions in Graphene-Containing Systems for Water Treatment and Beyond. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905756. [PMID: 32253804 DOI: 10.1002/adma.201905756] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/30/2020] [Indexed: 06/11/2023]
Abstract
Cation-π interactions are common in nature, especially in organisms. Their profound influences in chemistry, physics, and biology have been continuously investigated since they were discovered in 1981. However, the importance of cation-π interactions in materials science, regarding carbonaceous nanomaterials, has just been realized. The interplay between cations and delocalized polarizable π electrons of graphene would bring about significant changes to the intrinsic characteristics of graphene and greatly affect the device performance based on graphene and its derivatives. Here, the cation-π interactions in graphene containing systems for water treatment applications (e.g., separation membranes, adsorbents) are highlighted. The cross-linking effects caused by cation-π interactions contribute to membrane stability and selectivity and enhanced adsorption. Their roles in dominating the performance of graphene-based structures for other specific applications are also discussed. Relevant theoretical modeling and calculations are summarized to offer an in-depth understanding of the underlying mechanisms which can help in designing more functional materials and structures. Perspectives on the potential directions that deserve effort are also presented.
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Affiliation(s)
- Guoke Zhao
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Hongwei Zhu
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
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5
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Jiang LT, Bai PK, Ren FD, Wang JH, Liu B, Li YX. Theoretical evaluation to improve the performance of composite wax powder: cooperativity effects involving the strong Na+···π/σ and weak hydrogen-bonding interactions in the complex of graphene oxide with Na+ and CH4. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1612106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Le-tao Jiang
- School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China
- College of Gem and Material Technology, Hebei Geo University, Shijiazhuang, People’s Republic of China
| | - Pei-kang Bai
- School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China
| | - Fu-de Ren
- School of Chemical Engineering and Technology, North University of China, Taiyuan, People’s Republic of China
| | - Jian-hong Wang
- School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China
| | - Bin Liu
- School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China
| | - Yu-xin Li
- School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China
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Shi WJ, Ren FD. Cooperativity effect of the ππ interaction between drug and DNA on intercalative binding induced by H-bonds: a QM/QTAIM investigation of the curcuminadenineH 2O model system. Phys Chem Chem Phys 2019; 21:11871-11882. [PMID: 31119251 DOI: 10.1039/c9cp01667h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In order to reveal the nature of intercalative binding of drug to DNA, the cooperativity effect of the ππ interaction was investigated in the curcuminadenineH2O model system by applying a combined QM and QTAIM computational approach. The H-bonds between the electron-donating group of curcumin and adenine induce the formation of the ππ stacking. The introduction of H2O weakens the H-bonding and ππ interactions, leading to an anti-cooperativity effect, as is confirmed by the AIM (atoms in molecules) and RDG (reduced density gradient) analysis. Thus, it can be inferred that the anti-cooperative effect is the main driving force for the intercalative binding of drug to DNA bases, which is in agreement with many experimental phenomena. Therefore, the designed DNA-targeted intercalating drugs should possess not only hydrophobic moieties, but also strong electron-donating groups bound to the DNA bases with H-bonds, which can slow the variation rates of the strengths of the H-bonding and ππ interactions between drug and DNA bases in the anti-cooperative process, leading to the intercalation formation. The enthalpy change is the major factor driving the positive thermodynamic cooperativity.
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Affiliation(s)
- Wen-Jing Shi
- The Second Hospital of Shanxi Medical University, Taiyuan 030053, China.
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7
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Frankel EA, Bevilacqua PC. Complexity in pH-Dependent Ribozyme Kinetics: Dark pK a Shifts and Wavy Rate-pH Profiles. Biochemistry 2017; 57:483-488. [PMID: 29271644 DOI: 10.1021/acs.biochem.7b00784] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Charged bases occur in RNA enzymes, or ribozymes, where they play key roles in catalysis. Cationic bases donate protons and perform electrostatic catalysis, while anionic bases accept protons. We previously published simulations of rate-pH profiles for ribozymes in terms of species plots for the general acid and general base that have been useful for understanding how ribozymes respond to pH. In that study, we did not consider interaction between the general acid and general base or interaction with other species on the RNA. Since that report, diverse small ribozyme classes have been discovered, many of which have charged nucleobases or metal ions in the active site that can either directly interact and participate in catalysis or indirectly interact as "influencers". Herein, we simulate experimental rate-pH profiles in terms of species plots in which reverse protonated charged nucleobases interact. These analyses uncover two surprising features of pH-dependent enzyme kinetics. (1) Cooperativity between the general acid and general base enhances population of the functional forms of a ribozyme and manifests itself as hidden or "dark" pKa shifts, real pKa shifts that accelerate the reaction but are not readily observed by standard experimental approaches, and (2) influencers favorably shift the pKas of proton-transferring nucleobases and manifest themselves as "wavy" rate-pH profiles. We identify parallels with the protein enzyme literature, including reverse protonation and wavelike behavior, while pointing out that RNA is more prone to reverse protonation. The complexities uncovered, which arise from simple pairwise interactions, should aid deconvolution of complex rate-pH profiles for RNA and protein enzymes and suggest veiled catalytic devices for promoting catalysis that can be tested by experiment and calculation.
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Affiliation(s)
- Erica A Frankel
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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8
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Peacock J, Jaynes JB. Using competition assays to quantitatively model cooperative binding by transcription factors and other ligands. Biochim Biophys Acta Gen Subj 2017; 1861:2789-2801. [PMID: 28774855 PMCID: PMC5623634 DOI: 10.1016/j.bbagen.2017.07.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/27/2017] [Accepted: 07/29/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND The affinities of DNA binding proteins for target sites can be used to model the regulation of gene expression. These proteins can bind to DNA cooperatively, strongly impacting their affinity and specificity. However, current methods for measuring cooperativity do not provide the means to accurately predict binding behavior over a wide range of concentrations. METHODS We use standard computational and mathematical methods, and develop novel methods as described in Results. RESULTS We explore some complexities of cooperative binding, and develop an improved method for relating in vitro measurements to in vivo function, based on ternary complex formation. We derive expressions for the equilibria among the various complexes, and explore the limitations of binding experiments that model the system using a single parameter. We describe how to use single-ligand binding and ternary complex formation in tandem to determine parameters that have thermodynamic relevance. We develop an improved method for finding both single-ligand dissociation constants and concentrations simultaneously. We show how the cooperativity factor can be found when only one of the single-ligand dissociation constants can be measured. CONCLUSIONS The methods that we develop constitute an optimized approach to accurately model cooperative binding. GENERAL SIGNIFICANCE The expressions and methods we develop for modeling and analyzing DNA binding and cooperativity are applicable to most cases where multiple ligands bind to distinct sites on a common substrate. The parameters determined using these methods can be fed into models of higher-order cooperativity to increase their predictive power.
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Affiliation(s)
- Jacob Peacock
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - James B Jaynes
- Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States.
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9
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Solimannejad M, Hosseini SM, Zabardasti A. A computational study of interplay between hydride bonding and cation–π interactions: H-Mg-H···X···Y triads (X = Li +, Na +, Y = C 2H 2, C 2H 4, C 6H 6) as model systems. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1288933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Seyyedeh Marziyeh Hosseini
- Department of Chemistry, Faculty of Science, Arak University, Arak, Iran
- Department of Chemistry, Faculty of Science, Lorestan University, Khorramabad, Iran
| | - Abedien Zabardasti
- Department of Chemistry, Faculty of Science, Lorestan University, Khorramabad, Iran
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10
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Balcells D, Clot E, Eisenstein O, Nova A, Perrin L. Deciphering Selectivity in Organic Reactions: A Multifaceted Problem. Acc Chem Res 2016; 49:1070-8. [PMID: 27152927 DOI: 10.1021/acs.accounts.6b00099] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Computational chemistry has made a sustained contribution to the understanding of chemical reactions. In earlier times, half a century ago, the goal was to distinguish allowed from forbidden reactions (e.g., Woodward-Hoffmann rules), that is, reactions with low or high to very high activation barriers. A great achievement of computational chemistry was also to contribute to the determination of structures with the bonus of proposing a rationalization (e.g., anomeric effect, isolobal analogy, Gillespie valence shell pair electron repulsion rules and counter examples, Wade-Mingos rules for molecular clusters). With the development of new methods and the constant increase in computing power, computational chemists move to more challenging problems, close to the daily concerns of the experimental chemists, in determining the factors that make a reaction both efficient and selective: a key issue in organic synthesis. For this purpose, experimental chemists use advanced synthetic and analytical techniques to which computational chemists added other ways of determining reaction pathways. The transition states and intermediates contributing to the transformation of reactants into the desired and undesired products can now be determined, including their geometries, energies, charges, spin densities, spectroscopy properties, etc. Such studies remain challenging due to the large number of chemical species commonly present in the reactive media whose role may have to be determined. Calculating chemical systems as they are in the experiment is not always possible, bringing its own share of complexity through the large number of atoms and the associated large number of conformers to consider. Modeling the chemical species with smaller systems is an alternative that historically led to artifacts. Another important topic is the choice of the computational method. While DFT is widely used, the vast diversity of functionals available is both an opportunity and a challenge. Though chemical knowledge helps, the relevant computational method is best chosen in conjunction with the nature of the experimental systems and many studies have been concerned with this topic. We will not address this aspect but give references in the text. Usually, a computational study starts with the validation of the method by means of benchmark calculations vs accurate experimental data or state-of-the-art calculations. Finally, computational chemists can bring more than the sole determination of the reaction pathways through the analysis of the electronic structure. In our case, we have privileged the NBO analysis, which has the advantage of describing interactions on the basis of terms and concepts that are shared within the chemical community. In this Account, we have chosen to select representative reactions from our own work to highlight the diversity of situations than can be addressed nowadays. These include selective activation of C(sp(3))-H bonds, selective reactions with low energy barriers, involving closed shell or radical species, the role of noncovalent interactions, and the importance of considering side reactions.
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Affiliation(s)
- David Balcells
- Centre
for Theoretical and Computational Chemistry (CTCC) and The Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Eric Clot
- Institut
Charles Gerhardt, UMR 5253 CNRS-UM-ENSCM, Université de Montpellier, Place Eugène Bataillon, 34095
Cedex 5 Montpellier, France
| | - Odile Eisenstein
- Centre
for Theoretical and Computational Chemistry (CTCC) and The Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
- Institut
Charles Gerhardt, UMR 5253 CNRS-UM-ENSCM, Université de Montpellier, Place Eugène Bataillon, 34095
Cedex 5 Montpellier, France
| | - Ainara Nova
- Centre
for Theoretical and Computational Chemistry (CTCC) and The Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Lionel Perrin
- Univ Lyon, Université Lyon1, CNRS, INSA,
CPE-Lyon, ICBMS, UMR 5246, 43, Bd du 11 Novembre 1918, 69622 Cedex Villeurbanne, France
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11
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Abstract
On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host-guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π-π-stacking, dispersive forces, cation-π and anion-π interactions, and contributions from the hydrophobic effect. Cooperativity in host-guest complexes as well as in self-assembly, and entropy factors are briefly highlighted. Tables with typical values for single noncovalent free energies and polarity parameters are in the Supporting Information.
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Affiliation(s)
- Frank Biedermann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Hans-Jörg Schneider
- FR Organische Chemie der Universität des Saarlandes , D-66041 Saarbrücken, Germany
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12
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Affiliation(s)
- A. Subha Mahadevi
- Centre for Molecular Modelling, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India 500607
| | - G. Narahari Sastry
- Centre for Molecular Modelling, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India 500607
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13
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Kumbhar S, Jana S, Anoop A, Waller MP. Cooperativity in bimetallic glutathione complexes. J Mol Graph Model 2015; 62:1-10. [DOI: 10.1016/j.jmgm.2015.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/30/2015] [Accepted: 05/05/2015] [Indexed: 01/03/2023]
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14
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Affiliation(s)
- Mathias A.S. Hass
- Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Frans A.A. Mulder
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark;
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15
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Said AM, Hangauer DG. Binding cooperativity between a ligand carbonyl group and a hydrophobic side chain can be enhanced by additional H-bonds in a distance dependent manner: A case study with thrombin inhibitors. Eur J Med Chem 2015; 96:405-24. [DOI: 10.1016/j.ejmech.2015.03.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 03/21/2015] [Accepted: 03/25/2015] [Indexed: 01/07/2023]
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16
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Additivity or cooperativity: Which model can predict the influence of simultaneous incorporation of two or more functionalities in a ligand molecule? Eur J Med Chem 2015; 90:897-915. [DOI: 10.1016/j.ejmech.2014.11.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 10/10/2014] [Accepted: 11/27/2014] [Indexed: 11/19/2022]
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17
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Chowdhury S, Haehnel BM, Chanda B. A self-consistent approach for determining pairwise interactions that underlie channel activation. ACTA ACUST UNITED AC 2014; 144:441-55. [PMID: 25311637 PMCID: PMC4210424 DOI: 10.1085/jgp.201411184] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Net free-energy measurements can be combined with mutant cycle analysis to determine interaction energies between specific amino acid pairs during channel activation. Signaling proteins such as ion channels largely exist in two functional forms, corresponding to the active and resting states, connected by multiple intermediates. Multiparametric kinetic models based on sophisticated electrophysiological experiments have been devised to identify molecular interactions of these conformational transitions. However, this approach is arduous and is not suitable for large-scale perturbation analysis of interaction pathways. Recently, we described a model-free method to obtain the net free energy of activation in voltage- and ligand-activated ion channels. Here we extend this approach to estimate pairwise interaction energies of side chains that contribute to gating transitions. Our approach, which we call generalized interaction-energy analysis (GIA), combines median voltage estimates obtained from charge-voltage curves with mutant cycle analysis to ascertain the strengths of pairwise interactions. We show that, for a system with an arbitrary gating scheme, the nonadditive contributions of amino acid pairs to the net free energy of activation can be computed in a self-consistent manner. Numerical analyses of sequential and allosteric models of channel activation also show that this approach can measure energetic nonadditivities even when perturbations affect multiple transitions. To demonstrate the experimental application of this method, we reevaluated the interaction energies of six previously described long-range interactors in the Shaker potassium channel. Our approach offers the ability to generate detailed interaction energy maps in voltage- and ligand-activated ion channels and can be extended to any force-driven system as long as associated “displacement” can be measured.
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Affiliation(s)
- Sandipan Chowdhury
- Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705 Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705
| | - Benjamin M Haehnel
- Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705 Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705
| | - Baron Chanda
- Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705 Graduate Program in Biophysics and Department of Neuroscience, University of Wisconsin, Madison, WI 53705
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A B3LYP and MP2(full) theoretical investigation into cooperativity effects, aromaticity and thermodynamic properties in the Na(+)⋯benzonitrile⋯H2O ternary complex. J Mol Model 2014; 20:2341. [PMID: 25005001 DOI: 10.1007/s00894-014-2341-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 06/08/2014] [Indexed: 10/25/2022]
Abstract
The cooperativity effects between H-bonding and Na(+)⋯π or Na(+)⋯σ interactions in Na(+)⋯benzonitrile⋯H2O complexes were investigated using the B3LYP and MP2(full) methods with 6-311++G(2d,p) and aug-cc-pVTZ basis sets. The thermodynamic cooperativity and the influence of this cooperativity on aromaticity was evaluated by nucleus-independent chemical shifts (NICS). The results showed that the influence of the Na(+)⋯σ or Na(+)⋯π interaction on the hydrogen bond is more pronounced than that of the latter on the former. The cooperativity effect appeared in the Na(+)⋯σ interaction complex while the anti-cooperativity effect tended to be in the Na(+)⋯π system. The change in enthalpy is the major factor driving cooperativity. Thermodynamic cooperativity is not in accordance with the cooperativity effect evaluated by the change of interaction energy. The ring aromaticity of is weakened while the bond dissociation energy (BDE) of the C-CN bond increases upon ternary complex formation. The cooperativity effect (E coop) correlates with R c (NICS(1)ternary/NICS(1)binary) and ΔΔδ (Δδ ternary - Δδ binary) involving the ring and C ≡ N bond, as well as R BDE(C-CN) [BDE(C-CN)ternary/BDE(C-CN)binary], respectively. AIM (atoms in molecules) analysis confirms the existence of cooperativity.
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19
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A theoretical investigation into the cooperativity effect involving anionic hydrogen bond, thermodynamic property and aromaticity in Cl−⋯benzonitrile⋯H2O ternary complex. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.02.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Schaeffer G, Fuhr O, Fenske D, Lehn JM. Self-Assembly of a Highly Organized, Hexameric Supramolecular Architecture: Formation, Structure and Properties. Chemistry 2013; 20:179-86. [DOI: 10.1002/chem.201303186] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 11/12/2022]
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Izaguirre G, Qi L, Lima M, Olson ST. Identification of serpin determinants of specificity and selectivity for furin inhibition through studies of α1PDX (α1-protease inhibitor Portland)-serpin B8 and furin active-site loop chimeras. J Biol Chem 2013; 288:21802-14. [PMID: 23744066 DOI: 10.1074/jbc.m113.462804] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
α1-Protease inhibitor Portland (α1PDX) is an engineered serpin family inhibitor of the proprotein convertase (PC), furin, that exhibits high specificity but limited selectivity for inhibiting furin over other PC family proteases. Here, we characterize serpin B8, a natural inhibitor of furin, together with α1PDX-serpin B8 and furin-PC chimeras to identify determinants of serpin specificity and selectivity for furin inhibition. Replacing reactive center loop (RCL) sequences of α1PDX with those of serpin B8 demonstrated that both the P4-P1 RXXR recognition sequence as well as the P1'-P5' sequence are critical determinants of serpin specificity for furin. Alignments of PC catalytic domains revealed four variable active-site loops whose role in furin reactivity with serpin B8 was tested by engineering furin-PC loop chimeras. The furin(298-300) loop but not the other loops differentially affected furin reactivity with serpin B8 and α1PDX in a manner that depended on the serpin RCL-primed sequence. Modeling of the serpin B8-furin Michaelis complex identified serpin exosites in strand 3C close to the 298-300 loop whose substitution in α1PDX differentially affected furin reactivity depending on the furin loop and serpin RCL-primed sequences. These studies demonstrate that RCL-primed residues, strand 3C exosites, and the furin(298-300) loop are critical determinants of serpin reactivity with furin, which may be exploited in the design of specific and selective α1PDX inhibitors of PCs.
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Affiliation(s)
- Gonzalo Izaguirre
- Center for Molecular Biology of Oral Diseases and the Department of Periodontics, University of Illinois, Chicago, Illinois 60612, USA.
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22
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23
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Lehn JM. Perspectives in Chemistry-Steps towards Complex Matter. Angew Chem Int Ed Engl 2013; 52:2836-50. [DOI: 10.1002/anie.201208397] [Citation(s) in RCA: 474] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Indexed: 12/16/2022]
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24
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Krepl M, Otyepka M, Banáš P, Šponer J. Effect of Guanine to Inosine Substitution on Stability of Canonical DNA and RNA Duplexes: Molecular Dynamics Thermodynamics Integration Study. J Phys Chem B 2013; 117:1872-9. [DOI: 10.1021/jp311180u] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Miroslav Krepl
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, tr. 17
listopadu 12, 771 46 Olomouc, Czech Republic
| | - Pavel Banáš
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, tr. 17
listopadu 12, 771 46 Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
- CEITEC—Central European Institute of Technology, Campus Bohunice, Kamenice
5, 625 00 Brno, Czech Republic
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25
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Mahadevi AS, Sastry GN. Cation-π interaction: its role and relevance in chemistry, biology, and material science. Chem Rev 2012; 113:2100-38. [PMID: 23145968 DOI: 10.1021/cr300222d] [Citation(s) in RCA: 728] [Impact Index Per Article: 60.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- A Subha Mahadevi
- Molecular Modeling Group, CSIR-Indian Institute of Chemical Technology Tarnaka, Hyderabad 500 607, Andhra Pradesh, India
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26
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Nasief NN, Tan H, Kong J, Hangauer D. Water mediated ligand functional group cooperativity: the contribution of a methyl group to binding affinity is enhanced by a COO(-) group through changes in the structure and thermodynamics of the hydration waters of ligand-thermolysin complexes. J Med Chem 2012; 55:8283-302. [PMID: 22894131 DOI: 10.1021/jm300472k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ligand functional groups can modulate the contributions of one another to the ligand-protein binding thermodynamics, producing either positive or negative cooperativity. Data presented for four thermolysin phosphonamidate inhibitors demonstrate that the differential binding free energy and enthalpy caused by replacement of a H with a Me group, which binds in the well-hydrated S2' pocket, are more favorable in presence of a ligand carboxylate. The differential entropy is however less favorable. Dissection of these differential thermodynamic parameters, X-ray crystallography, and density-functional theory calculations suggest that these cooperativities are caused by variations in the thermodynamics of the complex hydration shell changes accompanying the H→Me replacement. Specifically, the COO(-) reduces both the enthalpic penalty and the entropic advantage of displacing water molecules from the S2' pocket and causes a subsequent acquisition of a more enthalpically, less entropically, favorable water network. This study contributes to understanding the important role water plays in ligand-protein binding.
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Affiliation(s)
- Nader N Nasief
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA.
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27
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Denisov IG, Sligar SG. A novel type of allosteric regulation: functional cooperativity in monomeric proteins. Arch Biochem Biophys 2012; 519:91-102. [PMID: 22245335 PMCID: PMC3329180 DOI: 10.1016/j.abb.2011.12.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 12/19/2011] [Accepted: 12/20/2011] [Indexed: 10/14/2022]
Abstract
Cooperative functional properties and allosteric regulation in cytochromes P450 play an important role in xenobiotic metabolism and define one of the main mechanisms of drug-drug interactions. Recent experimental results suggest that ability to bind simultaneously two or more small organic molecules can be the essential feature of cytochrome P450 fold, and often results in rich and complex pattern of allosteric behavior. Manifestations of non-Michaelis kinetics include homotropic and heterotropic activation and inhibition effects depending on the stoichiometric ratios of substrate and effector, changes in the regio- and stereospecificity of catalytic transformations, and often give rise to the clinically important drug-drug interactions. In addition, functional response of P450 systems is modulated by the presence of specific and non-specific effector molecules, metal ions, membrane incorporation, formation of homo- and hetero-oligomers, and interactions with the protein redox partners. In this article we briefly overview the main factors contributing to the allosteric effects in cytochromes P450 with the main focus on the sources of cooperative behavior in xenobiotic metabolizing monomeric heme enzymes with their conformational flexibility and extremely broad substrate specificity. The novel mechanism of functional cooperativity in P450 enzymes does not require substantial binding cooperativity, rather it implies the presence of one or more binding sites with higher affinity than the single catalytically active site in the vicinity of the heme iron.
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Affiliation(s)
- Ilia G. Denisov
- Department of Biochemistry, University of Illinois, Urbana, IL, 61801
| | - Stephen G. Sligar
- Department of Biochemistry, University of Illinois, Urbana, IL, 61801
- Beckman Institute, University of Illinois, Urbana, IL, 61801
- School of Molecular and Cellular Biology, University of Illinois, Urbana, IL, 61801
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28
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Gebhardt M, Hoffgaard F, Hamacher K, Kast SM, Moroni A, Thiel G. Membrane anchoring and interaction between transmembrane domains are crucial for K+ channel function. J Biol Chem 2011; 286:11299-306. [PMID: 21310959 PMCID: PMC3064186 DOI: 10.1074/jbc.m110.211672] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Revised: 01/27/2011] [Indexed: 11/06/2022] Open
Abstract
The small viral channel Kcv is a Kir-like K(+) channel of only 94 amino acids. With this simple structure, the tetramer of Kcv represents the pore module of all complex K(+) channels. To examine the structural contribution of the transmembrane domains (TMDs) to channel function, we performed Ala scanning mutagenesis of the two domains and tested the functionality of the mutants in a yeast complementation assay. The data reveal, in combination with computational models, that the upper halves of both TMDs, which face toward the external medium, are rather rigid, whereas the inner parts are more flexible. The rigidity of the outer TMD is conferred by a number of essential aromatic amino acids that face the membrane and probably anchor this domain in the bilayer. The inner TMD is intimately connected with the rigid part of the outer TMD via π···π interactions between a pair of aromatic amino acids. This structural principle is conserved within the viral K(+) channels and also present in Kir2.2, implying a general importance of this architecture for K(+) channel function.
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Affiliation(s)
| | - Franziska Hoffgaard
- the Computational Biology Group, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Kay Hamacher
- the Computational Biology Group, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Stefan M. Kast
- the Physikalische Chemie III, Technische Universität Dortmund, 44227 Dortmund, Germany, and
| | - Anna Moroni
- the Department of Biology and Consiglio Nazionale delle Ricerche Istituto di Biofisica-Milano, Università degli Studi di Milano, 20122 Milan, Italy
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29
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Zonta C, De Lucchi O, Motterle R, Serafini S. Cooperativity in benzotriazole-amine complexes: allosteric tuning of molecular recognition interfaces. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Deconstructing thermodynamic parameters of a coupled system from site-specific observables. Proc Natl Acad Sci U S A 2010; 107:18856-61. [PMID: 20944067 DOI: 10.1073/pnas.1003609107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cooperative interactions mediate information transfer between structural domains of a protein molecule and are major determinants of protein function and modulation. The prevalent theories to understand the thermodynamic origins of cooperativity have been developed to reproduce the complex behavior of a global thermodynamic observable such as ligand binding or enzyme activity. However, in most cases the measurement of a single global observable cannot uniquely define all the terms that fully describe the energetics of the system. Here we establish a theoretical groundwork for analyzing protein thermodynamics using site-specific information. Our treatment involves extracting a site-specific parameter (defined as χ value) associated with a structural unit. We demonstrate that, under limiting conditions, the χ value is related to the direct interaction terms associated with the structural unit under observation and its intrinsic activation energy. We also introduce a site-specific interaction energy term (χ(diff)) that is a function of the direct interaction energy of that site with every other site in the system. When combined with site-directed mutagenesis and other molecular level perturbations, analyses of χ values of site-specific observables may provide valuable insights into protein thermodynamics and structure.
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31
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Siegfried NA, Kierzek R, Bevilacqua PC. Role of unsatisfied hydrogen bond acceptors in RNA energetics and specificity. J Am Chem Soc 2010; 132:5342-4. [PMID: 20345162 DOI: 10.1021/ja9107726] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RNA plays essential roles in much of biology. These functions are dictated by structures mediated by hydrogen bonding, stacking, electrostatics, and steric interactions. Roles of unsatisfied hydrogen bond functionalities in these structures are less well understood. Herein, we evaluated the energetic contributions of unsatisfied hydrogen bonding groups by placing chemically modified substituents in select internal positions in RNA helices and conducting thermodynamic studies. We find that unsatisfied carbonyl groups make exceptional contributions to structure formation (approximately 3 kcal/mol in free energy), most likely due to a combination of strain and dehydration effects. Thus, unsatisfied hydrogen bonding groups are likely key determinants in the folding energetics and specificity of many RNA and DNA molecules and may be especially important in tertiary structure interactions.
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Affiliation(s)
- Nathan A Siegfried
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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32
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Gibson HW, Ge Z, Jones JW, Harich K, Pederson A, Dorn HC. Supramacromolecular chemistry: Self‐assembly of polystyrene‐based multi‐armed pseudorotaxane star polymers from multi‐topic C
60
derivatives. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/pola.23688] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Harry W. Gibson
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
| | - Zhongxin Ge
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
| | - Jason W. Jones
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
| | - Kim Harich
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
| | - Adam Pederson
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
| | - Harry C. Dorn
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061‐0212
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33
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Denisov IG, Frank DJ, Sligar SG. Cooperative properties of cytochromes P450. Pharmacol Ther 2009; 124:151-67. [PMID: 19555717 DOI: 10.1016/j.pharmthera.2009.05.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 05/28/2009] [Indexed: 02/07/2023]
Abstract
Cytochromes P450 form a large and important class of heme monooxygenases with a broad spectrum of substrates and corresponding functions, from steroid hormone biosynthesis to the metabolism of xenobiotics. Despite decades of study, the molecular mechanisms responsible for the complex non-Michaelis behavior observed with many members of this superfamily during metabolism, often termed 'cooperativity', remain to be fully elucidated. Although there is evidence that oligomerization may play an important role in defining the observed cooperativity, some monomeric cytochromes P450, particularly those involved in xenobiotic metabolism, also display this behavior due to their ability to simultaneously bind several substrate molecules. As a result, formation of distinct enzyme-substrate complexes with different stoichiometry and functional properties can give rise to homotropic and heterotropic cooperative behavior. This review aims to summarize the current understanding of cooperativity in cytochromes P450, with a focus on the nature of cooperative effects in monomeric enzymes.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, United States of America
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34
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Siegfried NA, Bevilacqua PC. Thinking inside the box: designing, implementing, and interpreting thermodynamic cycles to dissect cooperativity in RNA and DNA folding. Methods Enzymol 2009; 455:365-93. [PMID: 19289213 DOI: 10.1016/s0076-6879(08)04213-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Double and triple mutant thermodynamic cycles provide a means to dissect the cooperativity of RNA and DNA folding at both the secondary and tertiary structural levels through use of the thermodynamic box or cube. In this article, we describe three steps for applying thermodynamic cycles to nucleic acid folding, with considerations of both conceptual and experimental features. The first step is design of an appropriate system and development of hypotheses regarding which residues might interact. Next is implementing this design in terms of a tractable experimental strategy, with an emphasis on UV melting. The final step, and the one we emphasize the most, is interpreting mutant cycles in terms of coupling between specific residues in the RNA or DNA. Coupling free energy in the absence and presence of changes elsewhere in the molecule is discussed in terms of specific folding models, including stepwise folding and concerted changes. Last, we provide a practical section on the use of commercially available software (KaleidaGraph) to fit melting data, along with a consideration of error propagation. Along the way, specific examples are chosen from the literature to illustrate the methods. This article is intended to be accessible to the biochemist or biologist without extensive thermodynamics background.
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Affiliation(s)
- Nathan A Siegfried
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, USA
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35
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Thermodynamic characterization of pyrazole and azaindole derivatives binding to p38 mitogen-activated protein kinase using Biacore T100 technology and van’t Hoff analysis. Anal Biochem 2008; 383:255-64. [DOI: 10.1016/j.ab.2008.08.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/12/2008] [Accepted: 08/14/2008] [Indexed: 12/11/2022]
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36
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Bevilacqua PC, Blose JM. Structures, kinetics, thermodynamics, and biological functions of RNA hairpins. Annu Rev Phys Chem 2008; 59:79-103. [PMID: 17937599 DOI: 10.1146/annurev.physchem.59.032607.093743] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most RNA comprises one strand and therefore can fold back on itself to form complex structures. At the heart of these structures is the hairpin, which is composed of a stem having Watson-Crick base pairing and a loop wherein the backbone changes directionality. First, we review the structure of hairpins including diversity in the stem, loop, and closing base pair. The function of RNA hairpins in biology is discussed next, including roles for isolated hairpins, as well as hairpins in the context of complex tertiary structures. We describe the kinetics and thermodynamics of hairpin folding including models for hairpin folding, folding transition states, and the cooperativity of folding. Lastly, we discuss some ways in which hairpins can influence the folding and function of tertiary structures, both directly and indirectly. RNA hairpins provide a simple means of controlling gene expression that can be understood in the language of physical chemistry.
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Affiliation(s)
- Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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37
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Behringer H, Degenhard A, Schmid F. Coarse-grained lattice model for investigating the role of cooperativity in molecular recognition. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:031914. [PMID: 17930278 DOI: 10.1103/physreve.76.031914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Indexed: 05/25/2023]
Abstract
Equilibrium aspects of the molecular recognition of rigid biomolecules are investigated using coarse-grained lattice models. The analysis is carried out in two stages. First, an ensemble of probe molecules is designed with respect to the target biomolecule. The recognition ability of the probe ensemble is then investigated by calculating the free energy of association. The influence of cooperative and anticooperative effects accompanying the association of the target and probe molecules is studied. Numerical findings are presented and compared to analytical results which can be obtained in the limit of dominating cooperativity and in the mean-field formulation of the models.
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Affiliation(s)
- Hans Behringer
- Fakultät für Physik, Universität Bielefeld, D-33615 Bielefeld, Germany
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38
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Saro D, Li T, Rupasinghe C, Paredes A, Caspers N, Spaller MR. A thermodynamic ligand binding study of the third PDZ domain (PDZ3) from the mammalian neuronal protein PSD-95. Biochemistry 2007; 46:6340-52. [PMID: 17474715 PMCID: PMC2527733 DOI: 10.1021/bi062088k] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The thermodynamic parameters associated with the binding of several series of linear peptides to the third PDZ domain (PDZ3) of the postsynaptic density 95 protein (PSD-95) have been measured using isothermal titration calorimetry (ITC). Two strategies were pursued in developing these binding ligands: (1) systematic N-terminal truncation of sequences derived from the C-terminal regions of identified PDZ3-binding proteins (CRIPT, neuroligin-1, and citron) and (2) selective mutation of specific positions within a consensus hexapeptide (KKETEV) known to bind PDZ3. Each synthetically prepared peptide was used to titrate PDZ3, which yielded the changes in Gibbs free energy (DeltaG), enthalpy (DeltaH), and entropy (TDeltaS) for the binding event. Selected peptides were subjected to additional analysis, which entailed (1) measuring the change in heat capacity (DeltaCp) upon association, to assess the character of the binding interface, and (2) constructing thermodynamic double mutant cycles, to determine the presence of cooperative effects. From the first series, the CRIPT protein proved to be the better source for higher affinity sequences. From the second series, enhanced binding was associated with peptides that closely adhered to the established motif for class I PDZ domain C-termini, X-(T/S)-X-(V/I/L), and more specifically to a narrower motif of X-T-X-V. Further, in both series a length of six residues was necessary and sufficient to capture maximal affinity. In addition, there were significant influences upon binding by modifying the abutting "X" positions. The cumulative results provide greater detail into the specific nature of ligand binding to PDZ3 and will assist in the development of selective molecular probes for the study of this and structurally homologous PDZ domains.
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39
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Siegfried NA, Metzger SL, Bevilacqua PC. Folding cooperativity in RNA and DNA is dependent on position in the helix. Biochemistry 2007; 46:172-81. [PMID: 17198387 DOI: 10.1021/bi061375l] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Secondary structural motifs play essential roles in the folding and function of RNA and DNA molecules. Previous work from our lab compared the folding of small DNA and RNA hairpin loops containing a sheared GA pair [Moody, E. M., Feerar, J. C., and Bevilacqua, P. C. (2004) Biochemistry 43, 7992-7998]. We found that the small DNA hairpins fold in a highly cooperative manner with indirect coupling, while their RNA counterparts fold in a much less cooperative fashion and display direct coupling. Herein, we extend this study to the double-stranded helix. We carried out double mutant cycles on base pairs having identical nearest-neighbor contexts but located in either external or internal helical registers. In the external register, both RNA and DNA exhibit extensive folding cooperativity between the penultimate and terminal base pair, which is independent of mismatch identity. In contrast, DNA exhibits virtually no folding cooperativity in the center of the helix, while RNA maintains substantial coupling, which is dependent on mismatch identity. Two models account for these non-nearest-neighbor effects: one involves the unfavorable entropy of helix initiation common to DNA and RNA, and the other involves steric and electrostatic strain peculiar to RNA. These data show that RNA can display cooperativity less than, greater than, or equal to that of DNA depending on context and position.
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Affiliation(s)
- Nathan A Siegfried
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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40
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Cockroft SL, Hunter CA. Chemical double-mutant cycles: dissecting non-covalent interactions. Chem Soc Rev 2006; 36:172-88. [PMID: 17264921 DOI: 10.1039/b603842p] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thermodynamic double-mutant cycles and triple-mutant boxes are widely employed for the experimental quantification of non-covalent interactions and cooperative effects in proteins. This review describes the application of these powerful methodologies to the study of non-covalent interactions in synthetic systems.
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Affiliation(s)
- Scott L Cockroft
- Centre for Chemical Biology, Department of Chemistry, Krebs Institute for Biomolecular Science, University of Sheffield, S3 7HF, UK
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41
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Kormos BL, Baranger AM, Beveridge DL. A study of collective atomic fluctuations and cooperativity in the U1A-RNA complex based on molecular dynamics simulations. J Struct Biol 2006; 157:500-13. [PMID: 17194603 PMCID: PMC1994251 DOI: 10.1016/j.jsb.2006.10.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 10/02/2006] [Accepted: 10/04/2006] [Indexed: 11/21/2022]
Abstract
Cooperative interactions play an important role in recognition and binding in macromolecular systems. In this study, we find that cross-correlated atomic fluctuations can be used to identify cooperative networks in a protein-RNA system. The dynamics of the RRM-containing protein U1A-stem loop 2 RNA complex have been calculated theoretically from a 10 ns molecular dynamics (MD) simulation. The simulation was analyzed by calculating the covariance matrix of all atomic fluctuations. These matrix elements are then presented in the form of a two-dimensional grid, which displays fluctuations on a per residue basis. The results indicate the presence of strong, selective cross-correlated fluctuations throughout the RRM in U1A-RNA. The atomic fluctuations correspond well with previous biophysical studies in which a multiplicity of cooperative networks have been reported and indicate that the various networks identified in separate individual experiments are fluctuationally correlated into a hyper-network encompassing most of the RRM. The calculated results also correspond well with independent results from a statistical covariance analysis of 330 aligned RRM sequences. This method has significant implications as a predictive tool regarding cooperativity in the protein-nucleic acid recognition process.
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Affiliation(s)
- Bethany L Kormos
- Chemistry Department and Molecular Biophysics Program, Wesleyan University, 237 Church St., Middletown, CT 06459, USA.
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42
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Behringer H, Degenhard A, Schmid F. Coarse-grained lattice model for molecular recognition. PHYSICAL REVIEW LETTERS 2006; 97:128101. [PMID: 17026000 DOI: 10.1103/physrevlett.97.128101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Indexed: 05/12/2023]
Abstract
We present a simple model which allows us to investigate the equilibrium aspects of molecular recognition between rigid biomolecules on a generic level. Using a two-stage approach, which consists of a design and a testing step, the role of cooperativity and of varying bond strength in molecular recognition is investigated. Cooperativity is found to enhance selectivity. In complexes which require a high binding flexibility, a small number of strong bonds seems to be favored compared to a situation with many but weak bonds.
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Affiliation(s)
- Hans Behringer
- Fakultät für Physik, Universität Bielefeld, D-33615 Bielefeld, Germany
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43
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Przezdziak J, Tremmel S, Kretzschmar I, Beyermann M, Bienert M, Volkmer-Engert R. Probing the Ligand-Binding Specificity and Analyzing the Folding State of SPOT-Synthesized FBP28 WW Domain Variants. Chembiochem 2006; 7:780-8. [PMID: 16575938 DOI: 10.1002/cbic.200500408] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The WW domains are known as the smallest naturally occurring, monomeric, triple-stranded, antiparallel beta-sheet domains. Hence, we chose the FBP28 WW domain as a model to investigate the stability of the beta-sheet structure at the amino acid level in the context of its function (ligand binding). The structure-function relationship was investigated through a complete substitution analysis of the FBP28 WW domain, with variants synthesized as a cellulose-bound peptide array. The functionality of the FBP28 WW domain variants was examined by probing the peptide array for ligand binding. In addition, selected FBP28 WW domain variants were investigated by CD measurements to determine the stability of the antiparallel beta-sheet structure. We discuss the correlation between structure stability and functionality for the FBP28 WW domain, as well as the effect of ligand-induced structure stabilization.
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Affiliation(s)
- Jana Przezdziak
- Institut für Medizinische Immunologie, Charité-Universitätsmedizin Berlin, Hessische Strasse 3-4, 10115 Berlin, Germany
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Hobson D, Uhlenbeck OC. Alanine scanning of MS2 coat protein reveals protein-phosphate contacts involved in thermodynamic hot spots. J Mol Biol 2005; 356:613-24. [PMID: 16380130 DOI: 10.1016/j.jmb.2005.11.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/10/2005] [Accepted: 11/14/2005] [Indexed: 10/25/2022]
Abstract
The co-crystal structure of the MS2 coat protein dimer with its RNA operator reveals eight amino acid side-chains contacting seven of the RNA phosphates. These eight amino acids and five nearby control positions were individually changed to an alanine residue and the binding affinities of the mutant proteins to the RNA were determined. In general, the data agreed well with the crystal structure and previous RNA modification data. Interestingly, amino acid residues that are energetically most important for complex formation cluster in the middle of the RNA binding interface, forming thermodynamic hot spots, and are surrounded by energetically less relevant amino acids. In order to evaluate whether or not a given alanine mutation causes a global change in the RNA-protein interface, the affinities of the mutant proteins to RNAs containing one of 14 backbone modifications spanning the entire interface were determined. In three of six protein mutations tested, thermodynamic coupling between the site of the mutation and RNA groups that can be even more than 16 A away was detected. This suggests that, in some cases, the mutation may subtly alter the entire protein-RNA interface.
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Affiliation(s)
- Dagmar Hobson
- Department of Biochemistry, Molecular Biology, Cell Biology, Northwestern University 2205 Tech Drive, Hogan 2-100, Evanston, IL 60208, USA
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Costa T, Cotecchia S. Historical review: Negative efficacy and the constitutive activity of G-protein-coupled receptors. Trends Pharmacol Sci 2005; 26:618-24. [PMID: 16260046 DOI: 10.1016/j.tips.2005.10.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Revised: 08/15/2005] [Accepted: 10/10/2005] [Indexed: 01/16/2023]
Abstract
The idea that a receptor can produce signalling without agonist intervention and that several antagonists can be 'active' in repressing such spontaneous activity is contained in the concept of ligand-induced conformational changes. Yet, this idea was neglected by pharmacologists for many years. In this article, we review the events that brought inverse agonism and constitutive activity to general attention and made this phenomenon a topic of current research. We also suggest a classification of antagonists based on the cooperativity that links their primary site of interaction with other functional domains of the receptor.
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Affiliation(s)
- Tommaso Costa
- Department of Pharmacology, Istituto Superiore di Sanità, Italy.
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Chadim M, Díaz P, García-España E, Hodacová J, Latorre J, Liu-González M, Luis SV, Llinares JM, Závada J. Role of Anions on the Crystal Structures of Copper(II) and Zinc(II) Complexes of a Tunable Butterfly Cyclophane Macrocycle. Inorg Chem 2005; 44:7503-10. [PMID: 16212376 DOI: 10.1021/ic051099j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three crystal structures of a ditopic cyclophane ligand (L) in which two 1,5,8,12-tetraamine molecules have been attached through methylene spacers to the ortho positions of a benzene ring are reported. The first one (1) corresponds to the tetraprotonated free macrocycle (H4L4+) having two tetrachlorozincate(II) counteranions (C24H54O2N8Cl8Zn2, a = 9.1890(2) A, b = 14.0120(3) A, c = 15.3180(3) A, alpha = 89.2320(7) degrees , beta = 82.0740(6) degrees , gamma = 83.017(1) degrees , Z = 2.00, triclinic, P); the second one (2) is of a binuclear Cu2+ complex having coordinated chloride anions and perchlorate counteranions (C24H58O14N8Cl4Cu2 a = 9.9380(2) A, b = 30.2470(6) A, c = 53.143(1) A, orthorhombic, F2dd, Z = 18), and the third one (3) corresponds to an analogous Zn2+ complex that has been crystallized using triflate as counteranion (C26H(51.2)O(6.6)N8Cl2F6S2Zn2 a = 8.472(5) A, b = 9.310(5), c = 13.745(5) A, alpha = 84.262(5) degrees , beta = 77.490(5) degrees , gamma = 73.557(5) degrees , triclinic, P, Z = 2). The analysis of the crystallographic data clearly shows that the conformation of the macrocycle and, in consequence, the overall architecture of the crystals are controlled by the anions present in the moiety, pi-pi-stacking associations, and hydrogen bonding interactions. The protonation and stability constants for the formation of the Cu2+ and Zn2+ complexes in aqueous solution have been determined potentiometrically in 0.15 mol dm(-3) NaClO4 at 298.1 K. Intramolecular hydrogen bonding defines the protonation behavior of the compound. Positive cooperativity is observed in the formation of the Cu2+ complexes.
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Affiliation(s)
- Martin Chadim
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 166 10 Prague 6, Czech Republic
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Carçabal P, Jockusch RA, Hünig I, Snoek LC, Kroemer RT, Davis BG, Gamblin DP, Compagnon I, Oomens J, Simons JP. Hydrogen Bonding and Cooperativity in Isolated and Hydrated Sugars: Mannose, Galactose, Glucose, and Lactose. J Am Chem Soc 2005; 127:11414-25. [PMID: 16089470 DOI: 10.1021/ja0518575] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conformation of phenyl-substituted monosaccharides (mannose, galactose, and glucose) and their singly hydrated complexes has been investigated in the gas phase by means of a combination of mass selected, conformer specific ultraviolet and infrared double resonance hole burning spectroscopy experiments, and ab initio quantum chemistry calculations. In each case, the water molecule inserts into the carbohydrate at a position where it can replace a weak intramolecular interaction by two stronger intermolecular hydrogen bonds. The insertion can produce significant changes in the conformational preferences of the carbohydrates, and there is a clear preference for structures where cooperative effects enhance the stability of the monosaccharide conformers to which the water molecule chooses to bind. The conclusions drawn from the study of monosaccharide-water complexes are extended to the disaccharide lactose and discussed in the light of the underlying mechanisms that may be involved in the binding of carbohydrate assemblies to proteins and the involvement, or not, of key structural water molecules.
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Affiliation(s)
- Pierre Carçabal
- Chemistry Department, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ United Kingdom
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Ilies MA, Supuran CT, Scozzafava A. Therapeutic applications of serine protease inhibitors. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.12.8.1181] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Moody EM, Bevilacqua PC. Structural and energetic consequences of expanding a highly cooperative stable DNA hairpin loop. J Am Chem Soc 2004; 126:9570-7. [PMID: 15291560 DOI: 10.1021/ja048368+] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many hairpin loops are expanded versions of smaller, stable ones. Herein we investigate the extent to which the energetics and structure of d(cGNAg) hairpin loops will tolerate sequence variation. Changing the closing base pair from CG to GC was found to completely eliminate loop-loop interactions; in contrast, expanding the loop at the 3'-end resulted in similar energetics and nonadditivity parameters as the parent loop, suggesting that loop-loop interactions remain intact and highly coupled upon expansion. Together, these data suggest that the CG closing base pair forms an essential platform upon which a stable d(GNA) hairpin loop can fold and that this loop can undergo 3'-expansion with little effect to its structure or energetics.
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Affiliation(s)
- Ellen M Moody
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Chanda B, Asamoah OK, Bezanilla F. Coupling interactions between voltage sensors of the sodium channel as revealed by site-specific measurements. ACTA ACUST UNITED AC 2004; 123:217-30. [PMID: 14981134 PMCID: PMC2217449 DOI: 10.1085/jgp.200308971] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The voltage-sensing S4 segments in the sodium channel undergo conformational rearrangements in response to changes in the electric field. However, it remains unclear whether these structures move independently or in a coordinated manner. Previously, site-directed fluorescence measurements were shown to track S4 transitions in each of the four domains (Chanda, B., and F. Bezanilla. 2002. J. Gen. Physiol. 120:629–645). Here, using a similar technique, we provide direct evidence of coupling interactions between voltage sensors in the sodium channel. Pairwise interactions between S4s were evaluated by comparing site-specific conformational changes in the presence and absence of a gating perturbation in a distal domain. Reciprocity of effect, a fundamental property of thermodynamically coupled systems, was measured by generating converse mutants. The magnitude of a local gating perturbation induced by a remote S4 mutation depends on the coupling strength and the relative equilibrium positions of the two voltage sensors. In general, our data indicates that the movement of all four voltage sensors in the sodium channel are coupled to a varying extent. Moreover, a gating perturbation in S4-DI has the largest effect on the activation of S4-DIV and vice versa, demonstrating an energetic linkage between S4-DI and S4-DIV. This result suggests a physical mechanism by which the activation and inactivation process may be coupled in voltage-gated sodium channels. In addition, we propose that cooperative interactions between voltage sensors may be the mechanistic basis for the fast activation kinetics of the sodium channel.
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Affiliation(s)
- Baron Chanda
- Department of Physiology and Anesthesiology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Dr. South, Los Angeles, CA 90025, USA
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