1
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Hofmann H. All over or overall - Do we understand allostery? Curr Opin Struct Biol 2023; 83:102724. [PMID: 37898005 DOI: 10.1016/j.sbi.2023.102724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/30/2023]
Abstract
Allostery is probably the most important concept in the regulation of cellular processes. Models to explain allostery are plenty. Each sheds light on different aspects but their entirety conveys an ambiguous feeling of comprehension and disappointment. Here, I discuss the most popular allostery models, their roots, similarities, and limitations. All of them are thermodynamic models. Naturally this bears a certain degree of redundancy, which forms the center of this review. After sixty years, many questions remain unanswered, mainly because our human longing for causality as base for understanding is not satisfied by thermodynamics alone. A description of allostery in terms of pathways, i.e., as a temporal chain of events, has been-, and still is-, a missing piece of the puzzle.
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Affiliation(s)
- Hagen Hofmann
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel.
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2
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Madhurima K, Nandi B, Munshi S, Naganathan AN, Sekhar A. Functional regulation of an intrinsically disordered protein via a conformationally excited state. SCIENCE ADVANCES 2023; 9:eadh4591. [PMID: 37379390 PMCID: PMC10306299 DOI: 10.1126/sciadv.adh4591] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/23/2023] [Indexed: 06/30/2023]
Abstract
A longstanding goal in the field of intrinsically disordered proteins (IDPs) is to characterize their structural heterogeneity and pinpoint the role of this heterogeneity in IDP function. Here, we use multinuclear chemical exchange saturation (CEST) nuclear magnetic resonance to determine the structure of a thermally accessible globally folded excited state in equilibrium with the intrinsically disordered native ensemble of a bacterial transcriptional regulator CytR. We further provide evidence from double resonance CEST experiments that the excited state, which structurally resembles the DNA-bound form of cytidine repressor (CytR), recognizes DNA by means of a "folding-before-binding" conformational selection pathway. The disorder-to-order regulatory switch in DNA recognition by natively disordered CytR therefore operates through a dynamical variant of the lock-and-key mechanism where the structurally complementary conformation is transiently accessed via thermal fluctuations.
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Affiliation(s)
- Kulkarni Madhurima
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
| | - Bodhisatwa Nandi
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
| | - Sneha Munshi
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Athi N. Naganathan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
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3
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Evolutionary fine-tuning of residual helix structure in disordered proteins manifests in complex structure and lifetime. Commun Biol 2023; 6:63. [PMID: 36653471 PMCID: PMC9849366 DOI: 10.1038/s42003-023-04445-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
Transcription depends on complex networks, where folded hub proteins interact with intrinsically disordered transcription factors undergoing coupled folding and binding. For this, local residual structure, a prototypical feature of intrinsic disorder, is key. Here, we dissect the unexplored functional potential of residual structure by comparing structure, kinetics, and thermodynamics within the model system constituted of the DREB2A transcription factor interacting with the αα-hub RCD1-RST. To maintain biological relevance, we developed an orthogonal evolutionary approach for the design of variants with varying amounts of structure. Biophysical analysis revealed a correlation between the amount of residual helical structure and binding affinity, manifested in altered complex lifetime due to changed dissociation rate constants. It also showed a correlation between helical structure in free and bound DREB2A variants. Overall, this study demonstrated how evolution can balance and fine-tune residual structure to regulate complexes in coupled folding and binding, potentially affecting transcription factor competition.
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4
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Mitra S, Oikawa H, Rajendran D, Kowada T, Mizukami S, Naganathan AN, Takahashi S. Flexible Target Recognition of the Intrinsically Disordered DNA-Binding Domain of CytR Monitored by Single-Molecule Fluorescence Spectroscopy. J Phys Chem B 2022; 126:6136-6147. [PMID: 35969476 PMCID: PMC9422980 DOI: 10.1021/acs.jpcb.2c02791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/03/2022] [Indexed: 11/29/2022]
Abstract
The intrinsically disordered DNA-binding domain of cytidine repressor (CytR-DBD) folds in the presence of target DNA and regulates the expression of multiple genes in E. coli. To explore the conformational rearrangements in the unbound state and the target recognition mechanisms of CytR-DBD, we carried out single-molecule Förster resonance energy transfer (smFRET) measurements. The smFRET data of CytR-DBD in the absence of DNA show one major and one minor population assignable to an expanded unfolded state and a compact folded state, respectively. The population of the folded state increases and decreases upon titration with salt and denaturant, respectively, in an apparent two-state manner. The peak FRET efficiencies of both the unfolded and folded states change continuously with denaturant concentration, demonstrating the intrinsic flexibility of the DNA-binding domain and the deviation from a strict two-state transition. Remarkably, the CytR-DBD exhibits a compact structure when bound to both the specific and nonspecific DNA; however, the peak FRET efficiencies of the two structures are slightly but consistently different. The observed conformational heterogeneity highlights the potential structural changes required for CytR to bind variably spaced operator sequences.
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Affiliation(s)
- Shrutarshi Mitra
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Hiroyuki Oikawa
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Divya Rajendran
- Department
of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Toshiyuki Kowada
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Shin Mizukami
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Athi N. Naganathan
- Department
of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Satoshi Takahashi
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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5
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Camacho-Zarco AR, Schnapka V, Guseva S, Abyzov A, Adamski W, Milles S, Jensen MR, Zidek L, Salvi N, Blackledge M. NMR Provides Unique Insight into the Functional Dynamics and Interactions of Intrinsically Disordered Proteins. Chem Rev 2022; 122:9331-9356. [PMID: 35446534 PMCID: PMC9136928 DOI: 10.1021/acs.chemrev.1c01023] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Intrinsically disordered
proteins are ubiquitous throughout all
known proteomes, playing essential roles in all aspects of cellular
and extracellular biochemistry. To understand their function, it is
necessary to determine their structural and dynamic behavior and to
describe the physical chemistry of their interaction trajectories.
Nuclear magnetic resonance is perfectly adapted to this task, providing
ensemble averaged structural and dynamic parameters that report on
each assigned resonance in the molecule, unveiling otherwise inaccessible
insight into the reaction kinetics and thermodynamics that are essential
for function. In this review, we describe recent applications of NMR-based
approaches to understanding the conformational energy landscape, the
nature and time scales of local and long-range dynamics and how they
depend on the environment, even in the cell. Finally, we illustrate
the ability of NMR to uncover the mechanistic basis of functional
disordered molecular assemblies that are important for human health.
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Affiliation(s)
| | - Vincent Schnapka
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Serafima Guseva
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Anton Abyzov
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Wiktor Adamski
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Sigrid Milles
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | | | - Lukas Zidek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 82500 Brno, Czech Republic.,Central European Institute of Technology, Masaryk University, Kamenice 5, 82500 Brno, Czech Republic
| | - Nicola Salvi
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
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6
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Kulkarni P, Leite VBP, Roy S, Bhattacharyya S, Mohanty A, Achuthan S, Singh D, Appadurai R, Rangarajan G, Weninger K, Orban J, Srivastava A, Jolly MK, Onuchic JN, Uversky VN, Salgia R. Intrinsically disordered proteins: Ensembles at the limits of Anfinsen's dogma. BIOPHYSICS REVIEWS 2022; 3:011306. [PMID: 38505224 PMCID: PMC10903413 DOI: 10.1063/5.0080512] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/17/2022] [Indexed: 03/21/2024]
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack rigid 3D structure. Hence, they are often misconceived to present a challenge to Anfinsen's dogma. However, IDPs exist as ensembles that sample a quasi-continuum of rapidly interconverting conformations and, as such, may represent proteins at the extreme limit of the Anfinsen postulate. IDPs play important biological roles and are key components of the cellular protein interaction network (PIN). Many IDPs can interconvert between disordered and ordered states as they bind to appropriate partners. Conformational dynamics of IDPs contribute to conformational noise in the cell. Thus, the dysregulation of IDPs contributes to increased noise and "promiscuous" interactions. This leads to PIN rewiring to output an appropriate response underscoring the critical role of IDPs in cellular decision making. Nonetheless, IDPs are not easily tractable experimentally. Furthermore, in the absence of a reference conformation, discerning the energy landscape representation of the weakly funneled IDPs in terms of reaction coordinates is challenging. To understand conformational dynamics in real time and decipher how IDPs recognize multiple binding partners with high specificity, several sophisticated knowledge-based and physics-based in silico sampling techniques have been developed. Here, using specific examples, we highlight recent advances in energy landscape visualization and molecular dynamics simulations to discern conformational dynamics and discuss how the conformational preferences of IDPs modulate their function, especially in phenotypic switching. Finally, we discuss recent progress in identifying small molecules targeting IDPs underscoring the potential therapeutic value of IDPs. Understanding structure and function of IDPs can not only provide new insight on cellular decision making but may also help to refine and extend Anfinsen's structure/function paradigm.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Vitor B. P. Leite
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo 15054-000, Brazil
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Supriyo Bhattacharyya
- Translational Bioinformatics, Center for Informatics, Department of Computational and Quantitative Medicine, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Srisairam Achuthan
- Center for Informatics, Division of Research Informatics, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Divyoj Singh
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Rajeswari Appadurai
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | | | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Jose N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005-1892, USA
| | | | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
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7
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Golla H, Kannan A, Gopi S, Murugan S, Perumalsamy LR, Naganathan AN. Structural-Energetic Basis for Coupling between Equilibrium Fluctuations and Phosphorylation in a Protein Native Ensemble. ACS CENTRAL SCIENCE 2022; 8:282-293. [PMID: 35233459 PMCID: PMC8880421 DOI: 10.1021/acscentsci.1c01548] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Indexed: 06/14/2023]
Abstract
The functioning of proteins is intimately tied to their fluctuations in the native ensemble. The structural-energetic features that determine fluctuation amplitudes and hence the shape of the underlying landscape, which in turn determine the magnitude of the functional output, are often confounded by multiple variables. Here, we employ the FF1 domain from human p190A RhoGAP protein as a model system to uncover the molecular basis for phosphorylation of a buried tyrosine, which is crucial to the transcriptional activity associated with transcription factor TFII-I. Combining spectroscopy, calorimetry, statistical-mechanical modeling, molecular simulations, and in vitro phosphorylation assays, we show that the FF1 domain samples a diverse array of conformations in its native ensemble, some of which are phosphorylation-competent. Upon eliminating unfavorable charge-charge interactions through a single charge-reversal (K53E) or charge-neutralizing (K53Q) mutation, we observe proportionately lower phosphorylation extents due to the altered structural coupling, damped equilibrium fluctuations, and a more compact native ensemble. We thus establish a conformational selection mechanism for phosphorylation in the FF1 domain with K53 acting as a "gatekeeper", modulating the solvent exposure of the buried tyrosine. Our work demonstrates the role of unfavorable charge-charge interactions in governing functional events through the modulation of native ensemble characteristics, a feature that could be prevalent in ordered protein domains.
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Affiliation(s)
- Hemashree Golla
- Department
of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Adithi Kannan
- Department
of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Soundhararajan Gopi
- Department
of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sowmiya Murugan
- Department
of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Lakshmi R Perumalsamy
- Department
of Biomedical Sciences, Sri Ramachandra
Institute of Higher Education and Research, Chennai 600116, India
| | - Athi N. Naganathan
- Department
of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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8
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Molecular Simulations of Intrinsically Disordered Proteins and Their Binding Mechanisms. Methods Mol Biol 2022; 2376:343-362. [PMID: 34845619 DOI: 10.1007/978-1-0716-1716-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intrinsically disordered proteins (IDPs) lack well-defined secondary or tertiary structures in solution but are found to be involved in a wide range of critical cellular processes that highlight their functional importance. IDPs usually undergo folding upon binding to their targets. Such binding coupled to folding behavior has widened our perspective on the protein structure-dynamics-function paradigm in molecular biology. However, characterizing the folding upon binding mechanism of IDPs experimentally remains quite challenging. Molecular simulations emerge as a potentially powerful tool that offers information complementary to experiments. Here we present a general computational framework for the molecular simulations of IDP folding upon binding processes that combines all-atom molecular dynamics (MD) and coarse-grained simulations. The classical all-atom molecular dynamics approach using GPU acceleration allows the researcher to explore the properties of the IDP conformational ensemble, whereas coarse-grained structure-based models implemented with parameters carefully calibrated to available experimental measurements can be used to simulate the entire folding upon binding process. We also discuss a set of tools for the analysis of MD trajectories and describe the details of the computational protocol to follow so that it can be adapted by the user to study any IDP in isolation and in complex with partners.
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9
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Grau I, Nowé A, Vranken W. Interpreting a black box predictor to gain insights into early folding mechanisms. Comput Struct Biotechnol J 2021; 19:4919-4930. [PMID: 34527196 PMCID: PMC8433119 DOI: 10.1016/j.csbj.2021.08.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/21/2022] Open
Abstract
Protein folding and function are closely connected, but the exact mechanisms by which proteins fold remain elusive. Early folding residues (EFRs) are amino acids within a particular protein that induce the very first stages of the folding process. High-resolution EFR data are only available for few proteins, which has previously enabled the training of a protein sequence-based machine learning 'black box' predictor (EFoldMine). Such a black box approach does not allow a direct extraction of the 'early folding rules' embedded in the protein sequence, whilst such interpretation is essential to improve our understanding of how the folding process works. We here apply and investigate a novel 'grey box' approach to the prediction of EFRs from protein sequence to gain mechanistic residue-level insights into the sequence determinants of EFRs in proteins. We interpret the rule set for three datasets, a default set comprised of natural proteins, a scrambled set comprised of the scrambled default set sequences, and a set of de novo designed proteins. Finally, we relate these data to the secondary structure adopted in the folded protein and provide all information online via http://xefoldmine.bio2byte.be/, as a resource to help understand and steer early protein folding.
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Affiliation(s)
- Isel Grau
- Artificial Intelligence Laboratory, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Ann Nowé
- Artificial Intelligence Laboratory, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, ULB/VUB, Triomflaan, 1050 Brussels, Belgium
| | - Wim Vranken
- Artificial Intelligence Laboratory, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, ULB/VUB, Triomflaan, 1050 Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels 1050, Belgium.,VIB Structural Biology Research Centre, Brussels 1050, Belgium
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10
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Freitas FC, Ferreira PHB, Favaro DC, Oliveira RJD. Shedding Light on the Inhibitory Mechanisms of SARS-CoV-1/CoV-2 Spike Proteins by ACE2-Designed Peptides. J Chem Inf Model 2021; 61:1226-1243. [PMID: 33619962 PMCID: PMC7931628 DOI: 10.1021/acs.jcim.0c01320] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 01/07/2023]
Abstract
Angiotensin-converting enzyme 2 (ACE2) is the host cellular receptor that locks onto the surface spike protein of the 2002 SARS coronavirus (SARS-CoV-1) and of the novel, highly transmissible and deadly 2019 SARS-CoV-2, responsible for the COVID-19 pandemic. One strategy to avoid the virus infection is to design peptides by extracting the human ACE2 peptidase domain α1-helix, which would bind to the coronavirus surface protein, preventing the virus entry into the host cells. The natural α1-helix peptide has a stronger affinity to SARS-CoV-2 than to SARS-CoV-1. Another peptide was designed by joining α1 with the second portion of ACE2 that is far in the peptidase sequence yet grafted in the spike protein interface with ACE2. Previous studies have shown that, among several α1-based peptides, the hybrid peptidic scaffold is the one with the highest/strongest affinity for SARS-CoV-1, which is comparable to the full-length ACE2 affinity. In this work, binding and folding dynamics of the natural and designed ACE2-based peptides were simulated by the well-known coarse-grained structure-based model, with the computed thermodynamic quantities correlating with the experimental binding affinity data. Furthermore, theoretical kinetic analysis of native contact formation revealed the distinction between these processes in the presence of the different binding partners SARS-CoV-1 and SARS-CoV-2 spike domains. Additionally, our results indicate the existence of a two-state folding mechanism for the designed peptide en route to bind to the spike proteins, in contrast to a downhill mechanism for the natural α1-helix peptides. The presented low-cost simulation protocol demonstrated its efficiency in evaluating binding affinities and identifying the mechanisms involved in the neutralization of spike-ACE2 interaction by designed peptides. Finally, the protocol can be used as a computer-based screening of more potent designed peptides by experimentalists searching for new therapeutics against COVID-19.
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Affiliation(s)
- Frederico Campos Freitas
- Laboratório de Biofísica Teórica,
Departamento de Física, Instituto de Ciências Exatas, Naturais
e Educação, Universidade Federal do Triângulo
Mineiro, Uberaba, MG 38064-200, Brazil
| | - Paulo Henrique Borges Ferreira
- Laboratório de Biofísica Teórica,
Departamento de Física, Instituto de Ciências Exatas, Naturais
e Educação, Universidade Federal do Triângulo
Mineiro, Uberaba, MG 38064-200, Brazil
| | - Denize Cristina Favaro
- Departamento de Química Orgânica,
Instituto de Química, Universidade Estadual de
Campinas, São Paulo, SP 13083-970, Brazil
| | - Ronaldo Junio de Oliveira
- Laboratório de Biofísica Teórica,
Departamento de Física, Instituto de Ciências Exatas, Naturais
e Educação, Universidade Federal do Triângulo
Mineiro, Uberaba, MG 38064-200, Brazil
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11
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Jensen KS. Measuring and Analyzing Binding Kinetics of Coupled Folding and Binding Reactions Under Pseudo-First-Order Conditions. Methods Mol Biol 2021; 2141:629-650. [PMID: 32696381 DOI: 10.1007/978-1-0716-0524-0_32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Many intrinsically disordered proteins (IDPs) adopt a well-defined structure upon binding to their interaction partners. Kinetic characterization is a requirement for the investigation of the dynamics and mechanisms of these folding-upon-binding reactions. Here a protocol is described for the investigation of binding kinetics of bimolecular binding and folding reactions of IDPs to their ligand partner under pseudo-first-order conditions using stopped-flow mixing and fluorescence detection.
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Affiliation(s)
- Kristine Steen Jensen
- Department for Biophysical Chemistry, Center for Molecular Protein Science, LTH, Lund University, Lund, Sweden.
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12
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Allert MJ, Hellinga HW. Harnessing Environmental Ca 2+ for Extracellular Protein Thermostabilization. Biochemistry 2020; 59:3725-3740. [PMID: 32915552 DOI: 10.1021/acs.biochem.0c00449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ca2+ is the third-most prevalent metal ion in the environment. EF hands are common Ca2+-binding motifs found in both extracellular and intracellular proteins of eukaryotes and prokaryotes. Cytoplasmic EF hand proteins often mediate allosteric control of signal transduction pathway components in response to intracellular Ca2+ concentration fluctuations by coupling Ca2+ binding to changes in protein structure. We show that an extracellular structural Ca2+-binding site mediates protein thermostabilization by such conformational coupling as well. Binding Ca2+ to the EF hand of the extracellular (periplasmic) Escherichia coli glucose-galactose binding protein thermostabilizes this protein by ∼17 K relative to its Ca2+-free form. Using statistical thermodynamic analysis of a fluorescent conjugate of ecGGBP that reports simultaneously on ligand binding and multiple conformational states, we found that its Ca2+-mediated stabilization is determined by conformational coupling mechanisms in two independent conformational exchange reactions. Binding to folded and unfolded states determines the maximum Ca2+-mediated stability. A disorder → order transition accompanies the formation of the Ca2+ complex in the folded state and dictates the minimum Ca2+ concentration at which the Ca2+-bound state becomes dominant. Similar transitions also encode the structural changes necessary for Ca2+-mediated control elements in signal transduction pathways. Ca2+-mediated thermostabilization and allosteric control, therefore, share a fundamental conformational coupling mechanism, which may have implications for the evolution of EF hands.
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Affiliation(s)
- Malin J Allert
- Department of Biochemistry, Duke University Medical Center, P.O. Box 3711, Durham, North Carolina 27710, United States
| | - Homme W Hellinga
- Department of Biochemistry, Duke University Medical Center, P.O. Box 3711, Durham, North Carolina 27710, United States
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13
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Gerlach GJ, Carrock R, Stix R, Stollar EJ, Ball KA. A disordered encounter complex is central to the yeast Abp1p SH3 domain binding pathway. PLoS Comput Biol 2020; 16:e1007815. [PMID: 32925900 PMCID: PMC7514057 DOI: 10.1371/journal.pcbi.1007815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/24/2020] [Accepted: 08/15/2020] [Indexed: 12/20/2022] Open
Abstract
Protein-protein interactions are involved in a wide range of cellular processes. These interactions often involve intrinsically disordered proteins (IDPs) and protein binding domains. However, the details of IDP binding pathways are hard to characterize using experimental approaches, which can rarely capture intermediate states present at low populations. SH3 domains are common protein interaction domains that typically bind proline-rich disordered segments and are involved in cell signaling, regulation, and assembly. We hypothesized, given the flexibility of SH3 binding peptides, that their binding pathways include multiple steps important for function. Molecular dynamics simulations were used to characterize the steps of binding between the yeast Abp1p SH3 domain (AbpSH3) and a proline-rich IDP, ArkA. Before binding, the N-terminal segment 1 of ArkA is pre-structured and adopts a polyproline II helix, while segment 2 of ArkA (C-terminal) adopts a 310 helix, but is far less structured than segment 1. As segment 2 interacts with AbpSH3, it becomes more structured, but retains flexibility even in the fully engaged state. Binding simulations reveal that ArkA enters a flexible encounter complex before forming the fully engaged bound complex. In the encounter complex, transient nonspecific hydrophobic and long-range electrostatic contacts form between ArkA and the binding surface of SH3. The encounter complex ensemble includes conformations with segment 1 in both the forward and reverse orientation, suggesting that segment 2 may play a role in stabilizing the correct binding orientation. While the encounter complex forms quickly, the slow step of binding is the transition from the disordered encounter ensemble to the fully engaged state. In this transition, ArkA makes specific contacts with AbpSH3 and buries more hydrophobic surface. Simulating the binding between ApbSH3 and ArkA provides insight into the role of encounter complex intermediates and nonnative hydrophobic interactions for other SH3 domains and IDPs in general.
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Affiliation(s)
- Gabriella J. Gerlach
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Rachel Carrock
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Robyn Stix
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Elliott J. Stollar
- School of Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - K. Aurelia Ball
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
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14
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Monti A, Sturlese M, Caporale A, Roger JDA, Mascanzoni F, Ruvo M, Doti N. Design, synthesis, structural analysis and biochemical studies of stapled AIF(370-394) analogues as ligand of CypA. Biochim Biophys Acta Gen Subj 2020; 1864:129717. [PMID: 32861757 DOI: 10.1016/j.bbagen.2020.129717] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/28/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND The neuronal apoptotic process requires the nuclear translocation of Apoptosis Inducing Factor (AIF) in complex with Cyclophilin A (CypA) with consequent chromatin condensation and DNA degradation events. Targeting CypA by delivering an AIF-blocking peptide (AIF(370-394)) provides a significant neuroprotection, demonstrating the biological relevance of the AIF/CypA complex. To date pharmaceutical compounds targeting this complex are missing. METHODS We designed and synthesized a set of mono and bicyclic AIF(370-394) analogs containing both disulfide and 1,2,3-triazole bridges, in the attempt to both stabilize the peptide conformation and improve its binding affinity to CypA. Peptide structures in solution and in complex with CypA have been studied by circular dichroism (CD), Nuclear Magnetic Resonance (NMR) and molecular modeling. The ability of stapled peptides to interact with CypA was evaluated by using Epic Corning label free technique and Isothermal Titration Calorimetry experiments. RESULTS We identified a stapled peptide analogue of AIF(370-394) with a ten-fold improved affinity for CypA. Molecular modeling studies reveal that the new peptide acquires β-turn/β-fold structures and shares with the parent molecule the same binding region on CypA. CONCLUSIONS Data obtained provide invaluable assistance in designing new ligand of CypA for therapeutic approaches in neurodegenerative diseases. GENERAL SIGNIFICANCE Due to the crucial role of AIF/CypA complex formation in neurodegeneration, identification of selective inhibitors is of high importance for targeted therapies. We describe new bicyclic peptide inhibitors with improved affinity for CypA, investigating the kinetic, thermodynamic and structural effects of conformational constraints on the protein-ligand interaction, and their utility for drug design.
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Affiliation(s)
- Alessandra Monti
- Istituto di Biostrutture e Bioimmagini-CNR; Via Mezzocannone, 16, 80134 Napoli, Italy; DISTABIF, Università degli Studi della Campania Luigi Vanvitelli, Via Vivaldi 43, 81100 Caserta, CE, Italy
| | - Mattia Sturlese
- Molecular Modeling Section, Dipartimento di Scienze del Farmaco, Università di Padova, via F. Marzolo 5, 35131 Padova, Italy
| | - Andrea Caporale
- Istituto di Biostrutture e Bioimmagini-CNR; Via Mezzocannone, 16, 80134 Napoli, Italy
| | - Jessica De Almeida Roger
- Molecular Modeling Section, Dipartimento di Scienze del Farmaco, Università di Padova, via F. Marzolo 5, 35131 Padova, Italy
| | - Fabiola Mascanzoni
- Istituto di Biostrutture e Bioimmagini-CNR; Via Mezzocannone, 16, 80134 Napoli, Italy
| | - Menotti Ruvo
- Istituto di Biostrutture e Bioimmagini-CNR; Via Mezzocannone, 16, 80134 Napoli, Italy
| | - Nunzianna Doti
- Istituto di Biostrutture e Bioimmagini-CNR; Via Mezzocannone, 16, 80134 Napoli, Italy.
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15
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Gianni S, Jemth P. Affinity versus specificity in coupled binding and folding reactions. Protein Eng Des Sel 2020; 32:355-357. [PMID: 31397874 DOI: 10.1093/protein/gzz020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 06/17/2019] [Accepted: 07/04/2019] [Indexed: 01/08/2023] Open
Abstract
Intrinsically disordered protein regions may fold upon binding to an interaction partner. It is often argued that such coupled binding and folding enables the combination of high specificity with low affinity. The basic tenet is that an unfavorable folding equilibrium will make the overall binding weaker while maintaining the interaction interface. While theoretically solid, we argue that this concept may be misleading for intrinsically disordered proteins. In fact, experimental evidence suggests that interactions of disordered regions usually involve extended conformations. In such cases, the disordered region is exceptionally unlikely to fold into a bound conformation in the absence of its binding partner. Instead, these disordered regions can bind to their partners in multiple different conformations and then fold into the native bound complex, thus, if anything, increasing the affinity through folding. We concede that (de)stabilization of native structural elements such as helices will modulate affinity, but this could work both ways, decreasing or increasing the stability of the complex. Moreover, experimental data show that intrinsically disordered binding regions display a range of affinities and specificities dictated by the particular side chains and length of the disordered region and not necessarily by the fact that they are disordered. We find it more likely that intrinsically disordered regions are common in protein-protein interactions because they increase the repertoire of binding partners, providing an accessible route to evolve interactions rather than providing a stability-affinity trade-off.
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Affiliation(s)
- Stefano Gianni
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur-Fondazione Cenci Bolognetti and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome 00185, Italy
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, SE-75123 Uppsala, Sweden
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16
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Zhang XX, Tokmakoff A. Revealing the Dynamical Role of Co-solvents in the Coupled Folding and Dimerization of Insulin. J Phys Chem Lett 2020; 11:4353-4358. [PMID: 32401513 PMCID: PMC7850624 DOI: 10.1021/acs.jpclett.0c00982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solvent-protein interactions are important for protein biological functions, especially for a coupled folding and binding system such as insulin. By monitoring the change in the conformation of insulin dimers during dissociation with temperature-jump infrared spectroscopy, we show that co-solvents can significantly destabilize the dimers by perturbing their hydrophobic center. The transition from the native to intermediate dimer state is observed as the buried residues are exposed to solvents in the presence of 10% dimethyl sulfoxide and with α-helices unfolding when ethanol is present, which reduces the dissociation time dramatically to 50% and 20% of the value in a D2O solution, respectively. We propose a self-consistent analysis using complementary methods to resolve this coupled folding and binding process and obtain a much higher rate of monomer association than of intermediate folding. Our results demonstrate that the conformational changes are critical in dimer formation and strongly affected by co-solvents.
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Affiliation(s)
- Xin-Xing Zhang
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Andrei Tokmakoff
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
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17
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Investigation into Early Steps of Actin Recognition by the Intrinsically Disordered N-WASP Domain V. Int J Mol Sci 2019; 20:ijms20184493. [PMID: 31514372 PMCID: PMC6770570 DOI: 10.3390/ijms20184493] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 09/08/2019] [Indexed: 12/21/2022] Open
Abstract
Cellular regulation or signaling processes are mediated by many proteins which often have one or several intrinsically disordered regions (IDRs). These IDRs generally serve as binders to different proteins with high specificity. In many cases, IDRs undergo a disorder-to-order transition upon binding, following a mechanism between two possible pathways, the induced fit or the conformational selection. Since these mechanisms contribute differently to the kinetics of IDR associations, it is important to investigate them in order to gain insight into the physical factors that determine the biomolecular recognition process. The verprolin homology domain (V) of the Neural Wiskott-Aldrich Syndrome Protein (N-WASP), involved in the regulation of actin polymerization, is a typical example of IDR. It is composed of two WH2 motifs, each being able to bind one actin molecule. In this study, we investigated the early steps of the recognition process of actin by the WH2 motifs of N-WASP domain V. Using docking calculations and molecular dynamics simulations, our study shows that actin is first recognized by the N-WASP domain V regions which have the highest propensity to form transient α -helices. The WH2 motif consensus sequences "LKKV" subsequently bind to actin through large conformational changes of the disordered domain V.
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18
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Toto A, Troilo F, Visconti L, Malagrinò F, Bignon C, Longhi S, Gianni S. Binding induced folding: Lessons from the kinetics of interaction between N TAIL and XD. Arch Biochem Biophys 2019; 671:255-261. [PMID: 31326517 DOI: 10.1016/j.abb.2019.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/28/2019] [Accepted: 07/14/2019] [Indexed: 10/26/2022]
Abstract
Intrinsically Disordered Proteins (IDPs) are a class of protein that exert their function despite lacking a well-defined three-dimensional structure, which is sometimes achieved only upon binding to their natural ligands. This feature implies the folding of IDPs to be generally coupled with a binding event, representing an interesting challenge for kinetic studies. In this review, we recapitulate some of the most important findings of IDPs binding-induced folding mechanisms obtained by analyzing their binding kinetics. Furthermore, by focusing on the interaction between the Measles virus NTAIL protein, a prototypical IDP, and its physiological partner, the X domain, we recapitulate the major theoretical and experimental approaches that were used to describe binding induced folding.
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Affiliation(s)
- Angelo Toto
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Francesca Troilo
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Lorenzo Visconti
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Francesca Malagrinò
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Christophe Bignon
- Aix-Marseille University, CNRS, Architecture et Fonction des Macromolećules Biologiques (AFMB), UMR7257, Marseille, France
| | - Sonia Longhi
- Aix-Marseille University, CNRS, Architecture et Fonction des Macromolećules Biologiques (AFMB), UMR7257, Marseille, France.
| | - Stefano Gianni
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy.
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19
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Neira JL, Palomino-Schätzlein M, Ricci C, Ortore MG, Rizzuti B, Iovanna JL. Dynamics of the intrinsically disordered protein NUPR1 in isolation and in its fuzzy complexes with DNA and prothymosin α. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:140252. [PMID: 31325636 DOI: 10.1016/j.bbapap.2019.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022]
Abstract
Intrinsically disordered proteins (IDPs) explore diverse conformations in their free states and, a few of them, also in their molecular complexes. This functional plasticity is essential for the function of IDPs, although their dynamics in both free and bound states is poorly understood. NUPR1 is a protumoral multifunctional IDP, activated during the acute phases of pancreatitis. It interacts with DNA and other IDPs, such as prothymosin α (ProTα), with dissociation constants of ~0.5 μM, and a 1:1 stoichiometry. We studied the structure and picosecond-to-nanosecond (ps-ns) dynamics by using both NMR and SAXS in: (i) isolated NUPR1; (ii) the NUPR1/ProTα complex; and (iii) the NUPR1/double stranded (ds) GGGCGCGCCC complex. Our SAXS findings show that NUPR1 remained disordered when bound to either partner, adopting a worm-like conformation; the fuzziness of bound NUPR1 was also pinpointed by NMR. Residues with the largest values of the relaxation rates (R1, R1ρ, R2 and ηxy), in the free and bound species, were mainly clustered around the 30s region of the sequence, which agree with one of the protein hot-spots already identified by site-directed mutagenesis. Not only residues in this region had larger relaxation rates, but they also moved slower than the rest of the molecule, as indicated by the reduced spectral density approach (RSDA). Upon binding, the energy landscape of NUPR1 was not funneled down to a specific, well-folded conformation, but rather its backbone flexibility was kept, with distinct motions occurring at the hot-spot region.
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Affiliation(s)
- José L Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante), Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain.
| | | | - Caterina Ricci
- Department of Life and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy
| | - Maria Grazia Ortore
- Department of Life and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, Cubo 31 C, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Juan L Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13288 Marseille, France
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20
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Munshi S, Gopi S, Asampille G, Subramanian S, Campos LA, Atreya HS, Naganathan AN. Tunable order-disorder continuum in protein-DNA interactions. Nucleic Acids Res 2019; 46:8700-8709. [PMID: 30107436 PMCID: PMC6158747 DOI: 10.1093/nar/gky732] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/31/2018] [Indexed: 11/23/2022] Open
Abstract
DNA-binding protein domains (DBDs) sample diverse conformations in equilibrium facilitating the search and recognition of specific sites on DNA over millions of energetically degenerate competing sites. We hypothesize that DBDs have co-evolved to sense and exploit the strong electric potential from the array of negatively charged phosphate groups on DNA. We test our hypothesis by employing the intrinsically disordered DBD of cytidine repressor (CytR) as a model system. CytR displays a graded increase in structure, stability and folding rate on increasing the osmolarity of the solution that mimics the non-specific screening by DNA phosphates. Electrostatic calculations and an Ising-like statistical mechanical model predict that CytR exhibits features of an electric potential sensor modulating its dimensions and landscape in a unique distance-dependent manner, while DNA plays the role of a non-specific macromolecular chaperone. Accordingly, CytR binds its natural half-site faster than the diffusion-controlled limit and even random DNA conforming to an electrostatic-steering binding mechanism. Our work unravels for the first time the synergistic features of a natural electrostatic potential sensor, a novel binding mechanism driven by electrostatic frustration and disorder, and the role of DNA in promoting distance-dependent protein structural transitions critical for switching between specific and non-specific DNA-binding modes.
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Affiliation(s)
- Sneha Munshi
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Soundhararajan Gopi
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | | | - Sandhyaa Subramanian
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Luis A Campos
- National Biotechnology Center, Consejo Superior de Investigaciones Científicas, Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Hanudatta S Atreya
- NMR Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Athi N Naganathan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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21
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Arya S, Singh AK, Bhasne K, Dogra P, Datta A, Das P, Mukhopadhyay S. Femtosecond Hydration Map of Intrinsically Disordered α-Synuclein. Biophys J 2019; 114:2540-2551. [PMID: 29874605 DOI: 10.1016/j.bpj.2018.04.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 10/14/2022] Open
Abstract
Protein hydration water plays a fundamentally important role in protein folding, binding, assembly, and function. Little is known about the hydration water in intrinsically disordered proteins that challenge the conventional sequence-structure-function paradigm. Here, by combining experiments and simulations, we show the existence of dynamical heterogeneity of hydration water in an intrinsically disordered presynaptic protein, namely α-synuclein, implicated in Parkinson's disease. We took advantage of nonoccurrence of cysteine in the sequence and incorporated a number of cysteine residues at the N-terminal segment, the central amyloidogenic nonamyloid-β component (NAC) domain, and the C-terminal end of α-synuclein. We then labeled these cysteine variants using environment-sensitive thiol-active fluorophore and monitored the solvation dynamics using femtosecond time-resolved fluorescence. The site-specific femtosecond time-resolved experiments allowed us to construct the hydration map of α-synuclein. Our results show the presence of three dynamically distinct types of water: bulk, hydration, and confined water. The amyloidogenic NAC domain contains dynamically restrained water molecules that are strikingly different from the water molecules present in the other two domains. Atomistic molecular dynamics simulations revealed longer residence times for water molecules near the NAC domain and supported our experimental observations. Additionally, our simulations allowed us to decipher the molecular origin of the dynamical heterogeneity of water in α-synuclein. These simulations captured the quasi-bound water molecules within the NAC domain originating from a complex interplay between the local chain compaction and the sequence composition. Our findings from this synergistic experimental simulation approach suggest longer trapping of interfacial water molecules near the amyloidogenic hotspot that triggers the pathological conversion into amyloids via chain sequestration, chain desolvation, and entropic liberation of ordered water molecules.
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Affiliation(s)
- Shruti Arya
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Avinash K Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Karishma Bhasne
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Priyanka Dogra
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India.
| | - Payel Das
- Data Science Department, IBM Thomas J. Watson Research Center, Yorktown Heights, New York.
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India; Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, Punjab, India.
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22
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How Robust Is the Mechanism of Folding-Upon-Binding for an Intrinsically Disordered Protein? Biophys J 2019; 114:1889-1894. [PMID: 29694866 DOI: 10.1016/j.bpj.2018.03.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/15/2018] [Accepted: 03/20/2018] [Indexed: 12/18/2022] Open
Abstract
The mechanism of interaction of an intrinsically disordered protein (IDP) with its physiological partner is characterized by a disorder-to-order transition in which a recognition and a binding step take place. Even if the mechanism is quite complex, IDPs tend to bind their partner in a cooperative manner such that it is generally possible to detect experimentally only the disordered unbound state and the structured complex. The interaction between the disordered C-terminal domain of the measles virus nucleoprotein (NTAIL) and the X domain (XD) of the viral phosphoprotein allows us to detect and quantify the two distinct steps of the overall reaction. Here, we analyze the robustness of the folding of NTAIL upon binding to XD by measuring the effect on both the folding and binding steps of NTAIL when the structure of XD is modified. Because it has been shown that wild-type XD is structurally heterogeneous, populating an on-pathway intermediate under native conditions, we investigated the binding to 11 different site-directed variants of NTAIL of one particular variant of XD (I504A XD) that populates only the native state. Data reveal that the recognition and the folding steps are both affected by the structure of XD, indicating a highly malleable pathway. The experimental results are briefly discussed in the light of previous experiments on other IDPs.
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23
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Mesrouze Y, Bokhovchuk F, Izaac A, Meyerhofer M, Zimmermann C, Fontana P, Schmelzle T, Erdmann D, Furet P, Kallen J, Chène P. Adaptation of the bound intrinsically disordered protein YAP to mutations at the YAP:TEAD interface. Protein Sci 2019; 27:1810-1820. [PMID: 30058229 DOI: 10.1002/pro.3493] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 01/06/2023]
Abstract
Many interactions between proteins are mediated by intrinsically disordered regions (IDRs). Intrinsically disordered proteins (IDPs) do not adopt a stable three-dimensional structure in their unbound form, but they become more structured upon binding to their partners. In this communication, we study how a bound IDR adapts to mutations, preventing the formation of hydrogen bonds at the binding interface that needs a precise positioning of the interacting residues to be formed. We use as a model the YAP:TEAD interface, where one YAP (IDP) and two TEAD residues form hydrogen bonds via their side chain. Our study shows that the conformational flexibility of bound YAP and the reorganization of water molecules at the interface help to reduce the energetic constraints created by the loss of H-bonds at the interface. The residual flexibility/dynamic of bound IDRs and water might, therefore, be a key for the adaptation of IDPs to different interface landscapes and to mutations occurring at binding interfaces.
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Affiliation(s)
- Yannick Mesrouze
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Fedir Bokhovchuk
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Aude Izaac
- Chemical Biology & Therapeutics, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Marco Meyerhofer
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Catherine Zimmermann
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Patrizia Fontana
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Tobias Schmelzle
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Dirk Erdmann
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Pascal Furet
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Joerg Kallen
- Chemical Biology & Therapeutics, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Patrick Chène
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland
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Chan-Yao-Chong M, Deville C, Pinet L, van Heijenoort C, Durand D, Ha-Duong T. Structural Characterization of N-WASP Domain V Using MD Simulations with NMR and SAXS Data. Biophys J 2019; 116:1216-1227. [PMID: 30878202 DOI: 10.1016/j.bpj.2019.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 11/19/2022] Open
Abstract
Because of their large conformational heterogeneity, structural characterization of intrinsically disordered proteins (IDPs) is very challenging using classical experimental methods alone. In this study, we use NMR and small-angle x-ray scattering (SAXS) data with multiple molecular dynamics (MD) simulations to describe the conformational ensemble of the fully disordered verprolin homology domain of the neural Aldrich syndrome protein involved in the regulation of actin polymerization. First, we studied several back-calculation software of SAXS scattering intensity and optimized the adjustable parameters to accurately calculate the SAXS intensity from an atomic structure. We also identified the most appropriate force fields for MD simulations of this IDP. Then, we analyzed four conformational ensembles of neural Aldrich syndrome protein verprolin homology domain, two generated with the program flexible-meccano with or without NMR-derived information as input and two others generated by MD simulations with two different force fields. These four conformational ensembles were compared to available NMR and SAXS data for validation. We found that MD simulations with the AMBER-03w force field and the TIP4P/2005s water model are able to correctly describe the conformational ensemble of this 67-residue IDP at both local and global level.
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Affiliation(s)
- Maud Chan-Yao-Chong
- BioCIS, University Paris-Sud, CNRS UMR 8076, University Paris-Saclay, Châtenay-Malabry, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Célia Deville
- IGBMC, University of Strasbourg, CNRS UMR 7104, Illkirch, France
| | - Louise Pinet
- ICSN, CNRS UPR 2301, University Paris-Saclay, Gif-sur-Yvette, France
| | | | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
| | - Tâp Ha-Duong
- BioCIS, University Paris-Sud, CNRS UMR 8076, University Paris-Saclay, Châtenay-Malabry, France.
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25
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Kinetic and thermodynamic effects of phosphorylation on p53 binding to MDM2. Sci Rep 2019; 9:693. [PMID: 30679555 PMCID: PMC6345774 DOI: 10.1038/s41598-018-36589-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/15/2018] [Indexed: 02/03/2023] Open
Abstract
p53 is frequently mutated in human cancers. Its levels are tightly regulated by the E3 ubiquitin ligase MDM2. The complex between MDM2 and p53 is largely formed by the interaction between the N-terminal domain of MDM2 and the N-terminal transactivation (TA) domain of p53 (residues 15–29). We investigated the kinetic and thermodynamic basis of the MDM2/p53 interaction by using wild-type and mutant variants of the TA domain. We focus on the effects of phosphorylation at positions Thr18 and Ser20 including their substitution with phosphomimetics. Conformational propensities of the isolated peptides were investigated using in silico methods and experimentally by circular dichroism and 1H-NMR in aqueous solution. Both experimental and computational analyses indicate that the p53 peptides are mainly disordered in aqueous solution, with evidence of nascent helix around the Ser20-Leu25 region. Both phosphorylation and the phosphomimetics at Thr18 result in a decrease in the binding affinity by ten- to twenty-fold when compared to the wild-type. Phosphorylation and phosphomimetics at Ser20 result in a smaller decrease in the affinity. Mutation of Lys24 and Leu25 also disrupts the interaction. Our results may be useful for further development of peptide-based drugs targeting the MDM2/p53 interaction.
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26
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Crabtree MD, Shammas SL. Stopped-Flow Kinetic Techniques for Studying Binding Reactions of Intrinsically Disordered Proteins. Methods Enzymol 2018; 611:423-457. [PMID: 30471695 DOI: 10.1016/bs.mie.2018.09.026] [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] [Indexed: 12/25/2022]
Abstract
Intrinsically disordered proteins are abundant in signaling processes such as transcription. Suitable binding and unbinding rates of proteins with their partners are critical for allowing them to perform their biological roles. Understanding how these are achieved, and indeed designing strategies for intervening or modulating related biological processes, therefore requires kinetic studies. In this chapter, we describe stopped-flow-based methods for determining association and dissociation rate constants for pairs of macromolecular binding partners. We describe how to select the simplest appropriate model to describe the interaction, and highlight cases where it is possible to distinguish between induced fit and conformational selection binding mechanisms. Finally, we go on to describe methods for examining the role of electrostatic forces in binding processes, and for describing the transition state for binding processes that have folding associated with them.
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Affiliation(s)
- Michael D Crabtree
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Sarah L Shammas
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
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27
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Olson MA. Conformational Selection of a Polyproline Peptide by Ebola Virus VP30. Proteomics 2018; 18:e1800081. [PMID: 30302912 DOI: 10.1002/pmic.201800081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 09/18/2018] [Indexed: 11/09/2022]
Abstract
An adaptive temperature-based replica-exchange simulation of a peptide extracted from the Ebola virus nucleoprotein containing a polyproline sequence motif is reported. The simulation results of applying the CHARMM36m force field with a generalized Born solvent model is presented. Conformational heterogeneity is described by potentials of mean force (PMFs) for a set of reaction coordinates that define the topological fold space. Starting from an extended backbone conformation of the peptide observed in an X-ray crystallographic assembly with the Ebola virus protein VP30, the PMFs report a conformational landscape populated by chain excursions to collapsed states with limited transitions to either an extended fold or a canonical polyproline type II helix. Clustering of the conformations and applying an elastic network interpolation model yield a multistep pathway of conformational selection that minimizes the net transition-state cost from the population hub to the bound state. Related difference between the pathway endpoints taken from the PMFs reveal a significant free-energy penalty in reaching a population shift. To evaluate sequence fitness of the Ebola virus peptide in generating probability distributions, two human sequence variants are modeled and are found to produce profiles that show extensive deviations, thus suggesting either dissimilar binding mechanisms or the lack of recognition by VP30.
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Affiliation(s)
- Mark A Olson
- Department of Cell Biology and Biochemistry, Molecular and Translational Sciences Division, USAMRIID, Frederick, MD, 21702, USA
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28
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Li C, Clark LVT, Zhang R, Porebski BT, McCoey JM, Borg NA, Webb GI, Kass I, Buckle M, Song J, Woolfson A, Buckle AM. Structural Capacitance in Protein Evolution and Human Diseases. J Mol Biol 2018; 430:3200-3217. [PMID: 30111491 DOI: 10.1016/j.jmb.2018.06.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/18/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
Canonical mechanisms of protein evolution include the duplication and diversification of pre-existing folds through genetic alterations that include point mutations, insertions, deletions, and copy number amplifications, as well as post-translational modifications that modify processes such as folding efficiency and cellular localization. Following a survey of the human mutation database, we have identified an additional mechanism that we term "structural capacitance," which results in the de novo generation of microstructure in previously disordered regions. We suggest that the potential for structural capacitance confers select proteins with the capacity to evolve over rapid timescales, facilitating saltatory evolution as opposed to gradualistic canonical Darwinian mechanisms. Our results implicate the elements of protein microstructure generated by this distinct mechanism in the pathogenesis of a wide variety of human diseases. The benefits of rapidly furnishing the potential for evolutionary change conferred by structural capacitance are consequently counterbalanced by this accompanying risk. The phenomenon of structural capacitance has implications ranging from the ancestral diversification of protein folds to the engineering of synthetic proteins with enhanced evolvability.
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Affiliation(s)
- Chen Li
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Liah V T Clark
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Rory Zhang
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Benjamin T Porebski
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Julia M McCoey
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Natalie A Borg
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Geoffrey I Webb
- Faculty of Information Technology, Monash University, Clayton, Victoria 3800, Australia
| | - Itamar Kass
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Amai Proteins, Prof. A. D. Bergman 2B, Suite 212, Rehovot 7670504, Israel
| | - Malcolm Buckle
- LBPA, ENS Cachan, CNRS, Université Paris-Saclay, F-94235 Cachan, France
| | - Jiangning Song
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | | | - Ashley M Buckle
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.
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29
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Vancraenenbroeck R, Hofmann H. Occupancies in the DNA-Binding Pathways of Intrinsically Disordered Helix-Loop-Helix Leucine-Zipper Proteins. J Phys Chem B 2018; 122:11460-11467. [DOI: 10.1021/acs.jpcb.8b07351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Renee Vancraenenbroeck
- Department of Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel
| | - Hagen Hofmann
- Department of Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel
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30
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Kulkarni P, Solomon TL, He Y, Chen Y, Bryan PN, Orban J. Structural metamorphism and polymorphism in proteins on the brink of thermodynamic stability. Protein Sci 2018; 27:1557-1567. [PMID: 30144197 PMCID: PMC6194243 DOI: 10.1002/pro.3458] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/11/2018] [Indexed: 12/13/2022]
Abstract
The classical view of the structure-function paradigm advanced by Anfinsen in the 1960s is that a protein's function is inextricably linked to its three-dimensional structure and is encrypted in its amino acid sequence. However, it is now known that a significant fraction of the proteome consists of intrinsically disordered proteins (IDPs). These proteins populate a polymorphic ensemble of conformations rather than a unique structure but are still capable of performing biological functions. At the boundary, between well-ordered and inherently disordered states are proteins that are on the brink of stability, either weakly stable ordered systems or disordered but on the verge of being stable. In such marginal states, even relatively minor changes can significantly alter the energy landscape, leading to large-scale conformational remodeling. Some proteins on the edge of stability are metamorphic, with the capacity to switch from one fold topology to another in response to an environmental trigger (e.g., pH, temperature/salt, redox). Many IDPs, on the other hand, are marginally unstable such that small perturbations (e.g., phosphorylation, ligands) tip the balance over to a range of ordered, partially ordered, or even more disordered states. In general, the structural transitions described by metamorphic fold switches and polymorphic IDPs possess a number of common features including low or diminished stability, large-scale conformational changes, critical disordered regions, latent or attenuated binding sites, and expansion of function. We suggest that these transitions are, therefore, conceptually and mechanistically analogous, representing adjacent regions in the continuum of order/disorder transitions.
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Affiliation(s)
- Prakash Kulkarni
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Tsega L. Solomon
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Yanan He
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Yihong Chen
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - Philip N. Bryan
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
| | - John Orban
- W. M. Keck Laboratory for Structural BiologyUniversity of Maryland Institute for Bioscience and Biotechnology ResearchRockvilleMaryland20850
- Department of Chemistry and BiochemistryUniversity of MarylandCollege ParkMaryland20742
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31
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Zosel F, Mercadante D, Nettels D, Schuler B. A proline switch explains kinetic heterogeneity in a coupled folding and binding reaction. Nat Commun 2018; 9:3332. [PMID: 30127362 PMCID: PMC6102232 DOI: 10.1038/s41467-018-05725-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/19/2018] [Indexed: 11/22/2022] Open
Abstract
The interactions of intrinsically disordered proteins (IDPs) with their molecular targets are essential for the regulation of many cellular processes. IDPs can perform their functions while disordered, and they may fold to structured conformations on binding. Here we show that the cis/trans isomerization of peptidyl−prolyl bonds can have a pronounced effect on the interactions of IDPs. By single-molecule spectroscopy, we identify a conserved proline residue in NCBD (the nuclear-coactivator binding domain of CBP) whose cis/trans isomerization in the unbound state modulates the association and dissociation rates with its binding partner, ACTR. As a result, NCBD switches on a time scale of tens of seconds between two populations that differ in their affinities to ACTR by about an order of magnitude. Molecular dynamics simulations indicate as a cause reduced packing of the complex for the cis isomer. Peptidyl-prolyl cis/trans isomerization may be an important previously unidentified mechanism for regulating IDP interactions. How intrinsically disordered proteins (IDPs) undergo a coupled folding and binding reaction with their molecular targets remains to be understood. Here authors use single-molecule FRET to assess the contribution of cis/trans isomerization of peptidyl-prolyl bonds in regulating IDP interactions.
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Affiliation(s)
- Franziska Zosel
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Novo Nordisk A/S, Novo Nordisk Park 1, 2760, Måløv, Denmark
| | - Davide Mercadante
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland. .,Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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32
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Collins AP, Anderson PC. Complete Coupled Binding-Folding Pathway of the Intrinsically Disordered Transcription Factor Protein Brinker Revealed by Molecular Dynamics Simulations and Markov State Modeling. Biochemistry 2018; 57:4404-4420. [PMID: 29990433 DOI: 10.1021/acs.biochem.8b00441] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intrinsically disordered proteins (IDPs) make up a large class of proteins that lack stable structures in solution, existing instead as dynamic conformational ensembles. To perform their biological functions, many IDPs bind to other proteins or nucleic acids. Although IDPs are unstructured in solution, when they interact with binding partners, they fold into defined three-dimensional structures via coupled binding-folding processes. Because they frequently underlie IDP function, the mechanisms of this coupled binding-folding process are of great interest. However, given the flexibility inherent to IDPs and the sparse populations of intermediate states, it is difficult to reveal binding-folding pathways at atomic resolution using experimental methods. Computer simulations are another tool for studying these pathways at high resolution. Accordingly, we have applied 40 μs of unbiased molecular dynamics simulations and Markov state modeling to map the complete binding-folding pathway of a model IDP, the 59-residue C-terminal portion of the DNA binding domain of Drosophila melanogaster transcription factor Brinker (BrkDBD). Our modeling indicates that BrkDBD binds to its cognate DNA and folds in ∼50 μs by an induced fit mechanism, acquiring most of its stable secondary and tertiary structure only after it reaches the final binding site on the DNA. The protein follows numerous pathways en route to its bound and folded conformation, occasionally becoming stuck in kinetic traps. Each binding-folding pathway involves weakly bound, increasingly folded intermediate states located at different sites on the DNA surface. These findings agree with experimental data and provide additional insight into the BrkDBD folding mechanism and kinetics.
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Affiliation(s)
- Andrew P Collins
- Physical Sciences Division , University of Washington Bothell , Bothell , Washington 98011-8246 , United States
| | - Peter C Anderson
- Physical Sciences Division , University of Washington Bothell , Bothell , Washington 98011-8246 , United States
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33
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Crabtree MD, Mendonça CATF, Bubb QR, Clarke J. Folding and binding pathways of BH3-only proteins are encoded within their intrinsically disordered sequence, not templated by partner proteins. J Biol Chem 2018; 293:9718-9723. [PMID: 29716994 PMCID: PMC6016464 DOI: 10.1074/jbc.ra118.002791] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/24/2018] [Indexed: 12/03/2022] Open
Abstract
Intrinsically disordered regions are present in one-third of eukaryotic proteins and are overrepresented in cellular processes such as signaling, suggesting that intrinsically disordered proteins (IDPs) may have a functional advantage over folded proteins. Upon interacting with a partner macromolecule, a subset of IDPs can fold and bind to form a well-defined three-dimensional conformation. For example, disordered BH3-only proteins bind promiscuously to a large number of homologous BCL-2 family proteins, where they fold to a helical structure in a groove on the BCL-2–like protein surface. As two protein chains are involved in the folding reaction, and the structure is only formed in the presence of the partner macromolecule, this raises the question of where the folding information is encoded. Here, we examine these coupled folding and binding reactions to determine which component determines the folding and binding pathway. Using Φ value analysis to compare transition state interactions between the disordered BH3-only proteins PUMA and BID and the folded BCL-2–like proteins A1 and MCL-1, we found that, even though the BH3-only protein is disordered in isolation and requires a stabilizing partner to fold, its folding and binding pathway is encoded in the IDP itself; the reaction is not templated by the folded partner. We suggest that, by encoding both its transition state and level of residual structure, an IDP can evolve a specific kinetic profile, which could be a crucial functional advantage of disorder.
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Affiliation(s)
- Michael D Crabtree
- From the Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Carolina A T F Mendonça
- From the Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Quenton R Bubb
- From the Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jane Clarke
- From the Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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34
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Tsafou K, Tiwari PB, Forman-Kay JD, Metallo SJ, Toretsky JA. Targeting Intrinsically Disordered Transcription Factors: Changing the Paradigm. J Mol Biol 2018; 430:2321-2341. [PMID: 29655986 DOI: 10.1016/j.jmb.2018.04.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/21/2018] [Accepted: 04/05/2018] [Indexed: 12/21/2022]
Abstract
Increased understanding of intrinsically disordered proteins (IDPs) and protein regions has revolutionized our view of the relationship between protein structure and function. Data now support that IDPs can be functional in the absence of a single, fixed, three-dimensional structure. Due to their dynamic morphology, IDPs have the ability to display a range of kinetics and affinity depending on what the system requires, as well as the potential for large-scale association. Although several studies have shed light on the functional properties of IDPs, the class of intrinsically disordered transcription factors (TFs) is still poorly characterized biophysically due to their combination of ordered and disordered sequences. In addition, TF modulation by small molecules has long been considered a difficult or even impossible task, limiting functional probe development. However, with evolving technology, it is becoming possible to characterize TF structure-function relationships in unprecedented detail and explore avenues not available or not considered in the past. Here we provide an introduction to the biophysical properties of intrinsically disordered TFs and we discuss recent computational and experimental efforts toward understanding the role of intrinsically disordered TFs in biology and disease. We describe a series of successful TF targeting strategies that have overcome the perception of the "undruggability" of TFs, providing new leads on drug development methodologies. Lastly, we discuss future challenges and opportunities to enhance our understanding of the structure-function relationship of intrinsically disordered TFs.
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Affiliation(s)
- K Tsafou
- Department of Oncology and Pediatrics, Georgetown University, 3970 Reservoir Road Northwest, Washington, DC 20057, USA
| | - P B Tiwari
- Department of Oncology and Pediatrics, Georgetown University, 3970 Reservoir Road Northwest, Washington, DC 20057, USA
| | - J D Forman-Kay
- Molecular Medicine, The Hospital for Sick Children, Toronto M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto M5G 1X8, Canada
| | - S J Metallo
- Department of Chemistry, Georgetown University, Washington, DC 20057, USA
| | - J A Toretsky
- Department of Oncology and Pediatrics, Georgetown University, 3970 Reservoir Road Northwest, Washington, DC 20057, USA.
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35
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Paul F, Noé F, Weikl TR. Identifying Conformational-Selection and Induced-Fit Aspects in the Binding-Induced Folding of PMI from Markov State Modeling of Atomistic Simulations. J Phys Chem B 2018. [PMID: 29522679 DOI: 10.1021/acs.jpcb.7b12146] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unstructured proteins and peptides typically fold during binding to ligand proteins. A challenging problem is to identify the mechanism and kinetics of these binding-induced folding processes in experiments and atomistic simulations. In this Article, we present a detailed picture for the folding of the inhibitor peptide PMI into a helix during binding to the oncoprotein fragment 25-109Mdm2 obtained from atomistic, explicit-water simulations and Markov state modeling. We find that binding-induced folding of PMI is highly parallel and can occur along a multitude of pathways. Some pathways are induced-fit-like with binding occurring prior to PMI helix formation, while other pathways are conformational-selection-like with binding after helix formation. On the majority of pathways, however, binding is intricately coupled to folding, without clear temporal ordering. A central feature of these pathways is PMI motion on the Mdm2 surface, along the binding groove of Mdm2 or over the rim of this groove. The native binding groove of Mdm2 thus appears as an asymmetric funnel for PMI binding. Overall, binding-induced folding of PMI does not fit into the classical picture of induced fit or conformational selection that implies a clear temporal ordering of binding and folding events. We argue that this holds in general for binding-induced folding processes because binding and folding events in these processes likely occur on similar time scales and do exhibit the time-scale separation required for temporal ordering.
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Affiliation(s)
- Fabian Paul
- Max Planck Institute of Colloids and Interfaces , Department of Theory and Bio-Systems , Science Park Golm , 14424 Potsdam , Germany.,Freie Universität Berlin , Department of Mathematics and Computer Science , Arnimallee 6 , 14195 Berlin , Germany
| | - Frank Noé
- Freie Universität Berlin , Department of Mathematics and Computer Science , Arnimallee 6 , 14195 Berlin , Germany
| | - Thomas R Weikl
- Max Planck Institute of Colloids and Interfaces , Department of Theory and Bio-Systems , Science Park Golm , 14424 Potsdam , Germany
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36
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Mascarenhas NM, Terse VL, Gosavi S. Intrinsic Disorder in a Well-Folded Globular Protein. J Phys Chem B 2018; 122:1876-1884. [PMID: 29304275 DOI: 10.1021/acs.jpcb.7b12546] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The folded structure of the heterodimeric sweet protein monellin mimics single-chain proteins with topology β1-α1-β2-β3-β4-β5 (chain A: β3-β4-β5; chain B: β1-α1-β2). Furthermore, like naturally occurring single-chain proteins of a similar size, monellin folds cooperatively with no detectable intermediates. However, the two monellin chains, A and B, are marginally structured in isolation and fold only upon binding to each other. Thus, monellin presents a unique opportunity to understand the design of intrinsically disordered proteins that fold upon binding. Here, we study the folding of a single-chain variant of monellin (scMn) using simulations of an all heavy-atom structure-based model. These simulations can explain mechanistic details derived from scMn experiments performed using several different structural probes. scMn folds cooperatively in our structure-based simulations, as is also seen in experiments. We find that structure formation near the transition-state ensemble of scMn is not uniformly distributed but is localized to a hairpin-like structure which contains one strand from each chain (β2, β3). Thus, the sequence and the underlying energetics of heterodimeric monellin promote the early formation of the interchain interface (β2-β3). By studying computational scMn mutants whose "interchain" interactions are deleted, we infer that this energy distribution allows the two protein chains to remain largely disordered when this interface is not folded. From these results, we suggest that cutting the protein backbone of a globular protein between residues which lie within its folding nucleus may be one way to construct two disordered fragments which fold upon binding.
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Affiliation(s)
| | - Vishram L Terse
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research , Bangalore 560065, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research , Bangalore 560065, India
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37
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Arai M. Unified understanding of folding and binding mechanisms of globular and intrinsically disordered proteins. Biophys Rev 2018; 10:163-181. [PMID: 29307002 PMCID: PMC5899706 DOI: 10.1007/s12551-017-0346-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022] Open
Abstract
Extensive experimental and theoretical studies have advanced our understanding of the mechanisms of folding and binding of globular proteins, and coupled folding and binding of intrinsically disordered proteins (IDPs). The forces responsible for conformational changes and binding are common in both proteins; however, these mechanisms have been separately discussed. Here, we attempt to integrate the mechanisms of coupled folding and binding of IDPs, folding of small and multi-subdomain proteins, folding of multimeric proteins, and ligand binding of globular proteins in terms of conformational selection and induced-fit mechanisms as well as the nucleation–condensation mechanism that is intermediate between them. Accumulating evidence has shown that both the rate of conformational change and apparent rate of binding between interacting elements can determine reaction mechanisms. Coupled folding and binding of IDPs occurs mainly by induced-fit because of the slow folding in the free form, while ligand binding of globular proteins occurs mainly by conformational selection because of rapid conformational change. Protein folding can be regarded as the binding of intramolecular segments accompanied by secondary structure formation. Multi-subdomain proteins fold mainly by the induced-fit (hydrophobic collapse) mechanism, as the connection of interacting segments enhances the binding (compaction) rate. Fewer hydrophobic residues in small proteins reduce the intramolecular binding rate, resulting in the nucleation–condensation mechanism. Thus, the folding and binding of globular proteins and IDPs obey the same general principle, suggesting that the coarse-grained, statistical mechanical model of protein folding is promising for a unified theoretical description of all mechanisms.
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Affiliation(s)
- Munehito Arai
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
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38
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Dahal L, Shammas SL, Clarke J. Phosphorylation of the IDP KID Modulates Affinity for KIX by Increasing the Lifetime of the Complex. Biophys J 2018; 113:2706-2712. [PMID: 29262363 PMCID: PMC5770967 DOI: 10.1016/j.bpj.2017.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/04/2017] [Accepted: 10/10/2017] [Indexed: 11/17/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are known to undergo a range of posttranslational modifications, but by what mechanism do such modifications affect the binding of an IDP to its partner protein? We investigate this question using one such IDP, the kinase inducible domain (KID) of the transcription factor CREB, which interacts with the KIX domain of CREB-binding protein upon phosphorylation. As with many other IDPs, KID undergoes coupled folding and binding to form α-helical structure upon interacting with KIX. This single site phosphorylation plays an important role in the control of transcriptional activation in vivo. Here we show that, contrary to expectation, phosphorylation has no effect on association rates—unphosphorylated KID binds just as rapidly as pKID, the phosphorylated form—but rather, acts by increasing the lifetime of the complex. We propose that by controlling the lifetime of the bound complex of pKID:KIX via altering the dissociation rate, phosphorylation can facilitate effective control of transcription regulation.
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Affiliation(s)
- Liza Dahal
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Sarah L Shammas
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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39
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Salvi N, Abyzov A, Blackledge M. Atomic resolution conformational dynamics of intrinsically disordered proteins from NMR spin relaxation. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 102-103:43-60. [PMID: 29157493 DOI: 10.1016/j.pnmrs.2017.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 05/08/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful experimental approaches for investigating the conformational behaviour of intrinsically disordered proteins (IDPs). IDPs represent a significant fraction of all proteomes, and, despite their importance for understanding fundamental biological processes, the molecular basis of their activity still remains largely unknown. The functional mechanisms exploited by IDPs in their interactions with other biomolecules are defined by their intrinsic dynamic modes and associated timescales, justifying the considerable interest over recent years in the development of technologies adapted to measure and describe this behaviour. NMR spin relaxation delivers information-rich, site-specific data reporting on conformational fluctuations occurring throughout the molecule. Here we review recent progress in the use of 15N relaxation to identify local backbone dynamics and long-range chain-like motions in unfolded proteins.
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Affiliation(s)
- Nicola Salvi
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble 38044, France
| | - Anton Abyzov
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble 38044, France
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble 38044, France.
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40
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Paul F, Wehmeyer C, Abualrous ET, Wu H, Crabtree MD, Schöneberg J, Clarke J, Freund C, Weikl TR, Noé F. Protein-peptide association kinetics beyond the seconds timescale from atomistic simulations. Nat Commun 2017; 8:1095. [PMID: 29062047 PMCID: PMC5653669 DOI: 10.1038/s41467-017-01163-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
Understanding and control of structures and rates involved in protein ligand binding are essential for drug design. Unfortunately, atomistic molecular dynamics (MD) simulations cannot directly sample the excessively long residence and rearrangement times of tightly binding complexes. Here we exploit the recently developed multi-ensemble Markov model framework to compute full protein-peptide kinetics of the oncoprotein fragment 25-109Mdm2 and the nano-molar inhibitor peptide PMI. Using this system, we report, for the first time, direct estimates of kinetics beyond the seconds timescale using simulations of an all-atom MD model, with high accuracy and precision. These results only require explicit simulations on the sub-milliseconds timescale and are tested against existing mutagenesis data and our own experimental measurements of the dissociation and association rates. The full kinetic model reveals an overall downhill but rugged binding funnel with multiple pathways. The overall strong binding arises from a variety of conformations with different hydrophobic contact surfaces that interconvert on the milliseconds timescale.
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Affiliation(s)
- Fabian Paul
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, 14476, Potsdam, Germany
| | - Christoph Wehmeyer
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Esam T Abualrous
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Hao Wu
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Michael D Crabtree
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Johannes Schöneberg
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Christian Freund
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Thomas R Weikl
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, 14476, Potsdam, Germany
| | - Frank Noé
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA.
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41
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Saglam AS, Wang DW, Zwier MC, Chong LT. Flexibility vs Preorganization: Direct Comparison of Binding Kinetics for a Disordered Peptide and Its Exact Preorganized Analogues. J Phys Chem B 2017; 121:10046-10054. [PMID: 28992700 DOI: 10.1021/acs.jpcb.7b08486] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many intrinsically disordered proteins, which are prevalent in nature, fold only upon binding their structured partner proteins. Such proteins have been hypothesized to have a kinetic advantage over their folded, preorganized analogues in binding their partner proteins. Here we determined the effects of ligand preorganization on the kon for a biomedically important system: an intrinsically disordered p53 peptide ligand and the MDM2 protein receptor. Based on direct simulations of binding pathways, computed kon values for fully disordered and preorganized p53 peptide analogues were within error of each other, indicating little if any kinetic advantage to being disordered or preorganized for binding the MDM2 protein. We also examined the effects of increasing the concentration of MDM2 on the extent to which its mechanism of binding to the p53 peptide is induced fit vs conformational selection. Results predict that the mechanism is solely induced fit if the unfolded state of the peptide is more stable than its folded state; otherwise, the mechanism shifts from being dominated by conformational selection at low MDM2 concentration to induced fit at high MDM2 concentration. Taken together, our results are relevant to any protein binding process that involves a disordered peptide of a similar length that forms a single α-helix upon binding a partner protein. Such disorder-to-helix transitions are common among protein interactions of disordered proteins and are therefore of fundamental biological interest.
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Affiliation(s)
- A S Saglam
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - D W Wang
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - M C Zwier
- Department of Chemistry, Drake University , Des Moines, Iowa 50311, United States
| | - L T Chong
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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42
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Neira JL, Florencio FJ, Muro-Pastor MI. The isolated, twenty-three-residue-long, N-terminal region of the glutamine synthetase inactivating factor binds to its target. Biophys Chem 2017; 228:1-9. [DOI: 10.1016/j.bpc.2017.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 01/31/2023]
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43
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Exploring the Sequence-based Prediction of Folding Initiation Sites in Proteins. Sci Rep 2017; 7:8826. [PMID: 28821744 PMCID: PMC5562875 DOI: 10.1038/s41598-017-08366-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/10/2017] [Indexed: 11/23/2022] Open
Abstract
Protein folding is a complex process that can lead to disease when it fails. Especially poorly understood are the very early stages of protein folding, which are likely defined by intrinsic local interactions between amino acids close to each other in the protein sequence. We here present EFoldMine, a method that predicts, from the primary amino acid sequence of a protein, which amino acids are likely involved in early folding events. The method is based on early folding data from hydrogen deuterium exchange (HDX) data from NMR pulsed labelling experiments, and uses backbone and sidechain dynamics as well as secondary structure propensities as features. The EFoldMine predictions give insights into the folding process, as illustrated by a qualitative comparison with independent experimental observations. Furthermore, on a quantitative proteome scale, the predicted early folding residues tend to become the residues that interact the most in the folded structure, and they are often residues that display evolutionary covariation. The connection of the EFoldMine predictions with both folding pathway data and the folded protein structure suggests that the initial statistical behavior of the protein chain with respect to local structure formation has a lasting effect on its subsequent states.
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44
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Toto A, Bonetti D, De Simone A, Gianni S. Understanding the mechanism of binding between Gab2 and the C terminal SH3 domain from Grb2. Oncotarget 2017; 8:82344-82351. [PMID: 29137268 PMCID: PMC5669894 DOI: 10.18632/oncotarget.19323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/20/2017] [Indexed: 01/18/2023] Open
Abstract
Gab2 is a large disordered protein that regulates several cellular signalling pathways and is overexpressed in different forms of cancer. Because of its disordered nature, a detailed characterization of the mechanisms of recognition between Gab2 and its physiological partners is particularly difficult. Here we provide a detailed kinetic characterization of the binding reaction between Gab2 and the C-terminal SH3 domain of the growth factor receptor-bound protein 2 (Grb2). We demonstrate that Gab2 folds upon binding following an induced fit type mechanism, whereby recognition is characterized by the formation of an intermediate, in which Gab2 is primarily disordered. In this scenario, folding of Gab2 into the bound conformation occurs only after binding. However, an alanine scanning of the proline residues of Gab2 suggests that the intermediate contains some degree of native-like structure, which might play a role for the recognition event to take place. The results, which represent a fundamental step forward in the understanding of this functional protein-protein interaction, are discussed on the light of previous structural works on these proteins.
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Affiliation(s)
- Angelo Toto
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Daniela Bonetti
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, SW7 2AZ, London, UK
| | - Stefano Gianni
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, 00185, Rome, Italy
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45
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Eukaryotic transcription factors: paradigms of protein intrinsic disorder. Biochem J 2017; 474:2509-2532. [DOI: 10.1042/bcj20160631] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/19/2017] [Accepted: 05/05/2017] [Indexed: 12/17/2022]
Abstract
Gene-specific transcription factors (TFs) are key regulatory components of signaling pathways, controlling, for example, cell growth, development, and stress responses. Their biological functions are determined by their molecular structures, as exemplified by their structured DNA-binding domains targeting specific cis-acting elements in genes, and by the significant lack of fixed tertiary structure in their extensive intrinsically disordered regions. Recent research in protein intrinsic disorder (ID) has changed our understanding of transcriptional activation domains from ‘negative noodles’ to ID regions with function-related, short sequence motifs and molecular recognition features with structural propensities. This review focuses on molecular aspects of TFs, which represent paradigms of ID-related features. Through specific examples, we review how the ID-associated flexibility of TFs enables them to participate in large interactomes, how they use only a few hydrophobic residues, short sequence motifs, prestructured motifs, and coupled folding and binding for their interactions with co-activators, and how their accessibility to post-translational modification affects their interactions. It is furthermore emphasized how classic biochemical concepts like allostery, conformational selection, induced fit, and feedback regulation are undergoing a revival with the appreciation of ID. The review also describes the most recent advances based on computational simulations of ID-based interaction mechanisms and structural analysis of ID in the context of full-length TFs and suggests future directions for research in TF ID.
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46
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Bonetti D, Troilo F, Toto A, Brunori M, Longhi S, Gianni S. Analyzing the Folding and Binding Steps of an Intrinsically Disordered Protein by Protein Engineering. Biochemistry 2017; 56:3780-3786. [DOI: 10.1021/acs.biochem.7b00350] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniela Bonetti
- Istituto
Pasteur Italia-Fondazione Cenci Bolognetti, Istituto di Biologia e
Patologia Molecolari del CNR, Dipartimento di Scienze Biochimiche
“A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy
| | - Francesca Troilo
- Istituto
Pasteur Italia-Fondazione Cenci Bolognetti, Istituto di Biologia e
Patologia Molecolari del CNR, Dipartimento di Scienze Biochimiche
“A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy
- Aix-Marseille Univ, CNRS, Architecture et Fonction des
Macromolécules Biologiques (AFMB), UMR 7257, 13288 Marseille, France
| | - Angelo Toto
- Aix-Marseille Univ, CNRS, Architecture et Fonction des
Macromolécules Biologiques (AFMB), UMR 7257, 13288 Marseille, France
| | - Maurizio Brunori
- Istituto
Pasteur Italia-Fondazione Cenci Bolognetti, Istituto di Biologia e
Patologia Molecolari del CNR, Dipartimento di Scienze Biochimiche
“A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy
| | - Sonia Longhi
- Aix-Marseille Univ, CNRS, Architecture et Fonction des
Macromolécules Biologiques (AFMB), UMR 7257, 13288 Marseille, France
| | - Stefano Gianni
- Istituto
Pasteur Italia-Fondazione Cenci Bolognetti, Istituto di Biologia e
Patologia Molecolari del CNR, Dipartimento di Scienze Biochimiche
“A. Rossi Fanelli”, Sapienza Università di Roma, 00185 Rome, Italy
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47
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Luitz MP, Barth A, Crevenna AH, Bomblies R, Lamb DC, Zacharias M. Covalent dye attachment influences the dynamics and conformational properties of flexible peptides. PLoS One 2017; 12:e0177139. [PMID: 28542243 PMCID: PMC5441599 DOI: 10.1371/journal.pone.0177139] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/21/2017] [Indexed: 11/23/2022] Open
Abstract
Fluorescence spectroscopy techniques like Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) have become important tools for the in vitro and in vivo investigation of conformational dynamics in biomolecules. These methods rely on the distance-dependent quenching of the fluorescence signal of a donor fluorophore either by a fluorescent acceptor fluorophore (FRET) or a non-fluorescent quencher, as used in FCS with photoinduced electron transfer (PET). The attachment of fluorophores to the molecule of interest can potentially alter the molecular properties and may affect the relevant conformational states and dynamics especially of flexible biomolecules like intrinsically disordered proteins (IDP). Using the intrinsically disordered S-peptide as a model system, we investigate the impact of terminal fluorescence labeling on the molecular properties. We perform extensive molecular dynamics simulations on the labeled and unlabeled peptide and compare the results with in vitro PET-FCS measurements. Experimental and simulated timescales of end-to-end fluctuations were found in excellent agreement. Comparison between simulations with and without labels reveal that the π-stacking interaction between the fluorophore labels traps the conformation of S-peptide in a single dominant state, while the unlabeled peptide undergoes continuous conformational rearrangements. Furthermore, we find that the open to closed transition rate of S-peptide is decreased by at least one order of magnitude by the fluorophore attachment. Our approach combining experimental and in silico methods provides a benchmark for the simulations and reveals the significant effect that fluorescence labeling can have on the conformational dynamics of small biomolecules, at least for inherently flexible short peptides. The presented protocol is not only useful for comparing PET-FCS experiments with simulation results but provides a strategy to minimize the influence on molecular properties when chosing labeling positions for fluorescence experiments.
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Affiliation(s)
- Manuel P. Luitz
- Department Physik, T38, Technische Universität München, 85748 Garching, Germany
| | - Anders Barth
- Department Chemie, Physikalische Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Alvaro H. Crevenna
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Rainer Bomblies
- Department Physik, T38, Technische Universität München, 85748 Garching, Germany
| | - Don C. Lamb
- Department Chemie, Physikalische Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Martin Zacharias
- Department Physik, T38, Technische Universität München, 85748 Garching, Germany
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48
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Abstract
The weighted ensemble (WE) methodology orchestrates quasi-independent parallel simulations run with intermittent communication that can enhance sampling of rare events such as protein conformational changes, folding, and binding. The WE strategy can achieve superlinear scaling-the unbiased estimation of key observables such as rate constants and equilibrium state populations to greater precision than would be possible with ordinary parallel simulation. WE software can be used to control any dynamics engine, such as standard molecular dynamics and cell-modeling packages. This article reviews the theoretical basis of WE and goes on to describe successful applications to a number of complex biological processes-protein conformational transitions, (un)binding, and assembly processes, as well as cell-scale processes in systems biology. We furthermore discuss the challenges that need to be overcome in the next phase of WE methodological development. Overall, the combined advances in WE methodology and software have enabled the simulation of long-timescale processes that would otherwise not be practical on typical computing resources using standard simulation.
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Affiliation(s)
- Daniel M Zuckerman
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oregon 97239;
| | - Lillian T Chong
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260;
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49
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Abstract
Whereas protein-ligand binding affinities have long-established prominence, binding rate constants and binding mechanisms have gained increasing attention in recent years. Both new computational methods and new experimental techniques have been developed to characterize the latter properties. It is now realized that binding mechanisms, like binding rate constants, can and should be quantitatively determined. In this review, we summarize studies and synthesize ideas on several topics in the hope of providing a coherent picture of and physical insight into binding kinetics. The topics include microscopic formulation of the kinetic problem and its reduction to simple rate equations; computation of binding rate constants; quantitative determination of binding mechanisms; and elucidation of physical factors that control binding rate constants and mechanisms.
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Affiliation(s)
- Xiaodong Pang
- Department of Physics, Florida State University, Tallahassee, Florida 32306; .,Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Huan-Xiang Zhou
- Department of Physics, Florida State University, Tallahassee, Florida 32306; .,Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
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50
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Shammas SL. Mechanistic roles of protein disorder within transcription. Curr Opin Struct Biol 2017; 42:155-161. [PMID: 28262589 DOI: 10.1016/j.sbi.2017.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 12/28/2022]
Abstract
Understanding the interactions of proteins involved in transcriptional regulation is critical to describing biological systems because they control the expression profile of the cell. Yet sadly they belong to a less well biophysically characterized subset of proteins; they frequently contain long disordered regions that are highly dynamic. A key question therefore is, why? What functional roles does protein disorder play in transcriptional regulation? Experimental data exemplifying these roles are starting to emerge, with common themes being enabling complexity within networks and quick responses. Most recently a role for disorder in mediating phase transitions of membrane-less organelles has been proposed.
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Affiliation(s)
- Sarah L Shammas
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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