51
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Ithuralde RE, Roitberg AE, Turjanski AG. Structured and Unstructured Binding of an Intrinsically Disordered Protein as Revealed by Atomistic Simulations. J Am Chem Soc 2016; 138:8742-51. [PMID: 27348048 DOI: 10.1021/jacs.6b02016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Intrinsically disordered proteins (IDPs) are a set of proteins that lack a definite secondary structure in solution. IDPs can acquire tertiary structure when bound to their partners; therefore, the recognition process must also involve protein folding. The nature of the transition state (TS), structured or unstructured, determines the binding mechanism. The characterization of the TS has become a major challenge for experimental techniques and molecular simulations approaches since diffusion, recognition, and binding is coupled to folding. In this work we present atomistic molecular dynamics (MD) simulations that sample the free energy surface of the coupled folding and binding of the transcription factor c-myb to the cotranscription factor CREB binding protein (CBP). This process has been recently studied and became a model to study IDPs. Despite the plethora of available information, we still do not know how c-myb binds to CBP. We performed a set of atomistic biased MD simulations running a total of 15.6 μs. Our results show that c-myb folds very fast upon binding to CBP with no unique pathway for binding. The process can proceed through both structured or unstructured TS's with similar probabilities. This finding reconciles previous seemingly different experimental results. We also performed Go-type coarse-grained MD of several structured and unstructured models that indicate that coupled folding and binding follows a native contact mechanism. To the best of our knowledge, this is the first atomistic MD simulation that samples the free energy surface of the coupled folding and binding processes of IDPs.
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Affiliation(s)
- Raúl Esteban Ithuralde
- Departamento de Química Biológica/Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, IQUIBICEN/INQUIMAE-UBA/CONICET, Universidad de Buenos Aires, Ciudad Universitaria , Intendente Güiraldes 2160, Pabellón II, Buenos Aires C1428EGA, Argentina
| | - Adrián Enrique Roitberg
- Department of Chemistry, University of Florida , PO Box 117200, Gainesville, Florida 32611-7200, United States
| | - Adrián Gustavo Turjanski
- Departamento de Química Biológica/Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, IQUIBICEN/INQUIMAE-UBA/CONICET, Universidad de Buenos Aires, Ciudad Universitaria , Intendente Güiraldes 2160, Pabellón II, Buenos Aires C1428EGA, Argentina
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52
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Order-Disorder Transitions in the Cardiac Troponin Complex. J Mol Biol 2016; 428:2965-77. [PMID: 27395017 DOI: 10.1016/j.jmb.2016.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/21/2016] [Accepted: 06/29/2016] [Indexed: 12/26/2022]
Abstract
The troponin complex is a molecular switch that ties shifting intracellular calcium concentration to association and dissociation of actin and myosin, effectively allowing excitation-contraction coupling in striated muscle. Although there is a long history of muscle biophysics and structural biology, many of the mechanistic details that enable troponin's function remain incompletely understood. This review summarizes the current structural understanding of the troponin complex on the muscle thin filament, focusing on conformational changes in flexible regions of the troponin I subunit. In particular, we focus on order-disorder transitions in the C-terminal domain of troponin I, which have important implications in cardiac disease and could also have potential as a model system for the study of coupled binding and folding.
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53
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Pantoja-Uceda D, Neira JL, Saelices L, Robles-Rengel R, Florencio FJ, Muro-Pastor MI, Santoro J. Dissecting the Binding between Glutamine Synthetase and Its Two Natively Unfolded Protein Inhibitors. Biochemistry 2016; 55:3370-82. [DOI: 10.1021/acs.biochem.6b00072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - José L. Neira
- Instituto
de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain
- Instituto
de Biocomputación y Física de Sistemas Complejos (BIFI),
Unidad Asociada IQFR-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Lorena Saelices
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 41092 Seville, Spain
| | - Rocío Robles-Rengel
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 41092 Seville, Spain
| | - Francisco J. Florencio
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 41092 Seville, Spain
| | - M. Isabel Muro-Pastor
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, 41092 Seville, Spain
| | - Jorge Santoro
- Instituto
de Química Física Rocasolano (IQFR), CSIC, 28006 Madrid, Spain
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54
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Umezawa K, Ohnuki J, Higo J, Takano M. Intrinsic disorder accelerates dissociation rather than association. Proteins 2016; 84:1124-33. [DOI: 10.1002/prot.25057] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/16/2016] [Accepted: 04/24/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Koji Umezawa
- Department of Pure and Applied Physics; Waseda University; Okubo 3-4-1, Shinjuku-Ku Tokyo 169-8555 Japan
| | - Jun Ohnuki
- Department of Pure and Applied Physics; Waseda University; Okubo 3-4-1, Shinjuku-Ku Tokyo 169-8555 Japan
| | - Junichi Higo
- Institute for Protein Research, Osaka University; Suita Osaka 565-0871 Japan
| | - Mitsunori Takano
- Department of Pure and Applied Physics; Waseda University; Okubo 3-4-1, Shinjuku-Ku Tokyo 169-8555 Japan
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55
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Shammas SL, Crabtree MD, Dahal L, Wicky BIM, Clarke J. Insights into Coupled Folding and Binding Mechanisms from Kinetic Studies. J Biol Chem 2016; 291:6689-95. [PMID: 26851275 PMCID: PMC4807256 DOI: 10.1074/jbc.r115.692715] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Intrinsically disordered proteins (IDPs) are characterized by a lack of persistent structure. Since their identification more than a decade ago, many questions regarding their functional relevance and interaction mechanisms remain unanswered. Although most experiments have taken equilibrium and structural perspectives, fewer studies have investigated the kinetics of their interactions. Here we review and highlight the type of information that can be gained from kinetic studies. In particular, we show how kinetic studies of coupled folding and binding reactions, an important class of signaling event, are needed to determine mechanisms.
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Affiliation(s)
- Sarah L Shammas
- From the Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Michael D Crabtree
- From the Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Liza Dahal
- From the Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Basile I M Wicky
- From the Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jane Clarke
- From the Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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56
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Dyson HJ, Wright PE. Role of Intrinsic Protein Disorder in the Function and Interactions of the Transcriptional Coactivators CREB-binding Protein (CBP) and p300. J Biol Chem 2016; 291:6714-22. [PMID: 26851278 DOI: 10.1074/jbc.r115.692020] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The transcriptional coactivators CREB-binding protein (CBP) and p300 undergo a particularly rich set of interactions with disordered and partly ordered partners, as a part of their ubiquitous role in facilitating transcription of genes. CBP and p300 contain a number of small structured domains that provide scaffolds for the interaction of disordered transactivation domains from a wide variety of partners, including p53, hypoxia-inducible factor 1α (HIF-1α), NF-κB, and STAT proteins, and are the targets for the interactions of disordered viral proteins that compete with cellular factors to disrupt signaling and subvert the cell cycle. The functional diversity of the CBP/p300 interactome provides an excellent example of the power of intrinsic disorder to facilitate the complexity of living systems.
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Affiliation(s)
- H Jane Dyson
- From the Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037-1000
| | - Peter E Wright
- From the Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037-1000
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57
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Gianni S, Dogan J, Jemth P. Coupled binding and folding of intrinsically disordered proteins: what can we learn from kinetics? Curr Opin Struct Biol 2016; 36:18-24. [DOI: 10.1016/j.sbi.2015.11.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/13/2015] [Accepted: 11/26/2015] [Indexed: 12/16/2022]
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58
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Gruet A, Dosnon M, Blocquel D, Brunel J, Gerlier D, Das RK, Bonetti D, Gianni S, Fuxreiter M, Longhi S, Bignon C. Fuzzy regions in an intrinsically disordered protein impair protein-protein interactions. FEBS J 2016; 283:576-94. [PMID: 26684000 DOI: 10.1111/febs.13631] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 11/22/2015] [Accepted: 12/15/2015] [Indexed: 12/13/2022]
Abstract
Despite the partial disorder-to-order transition that intrinsically disordered proteins often undergo upon binding to their partners, a considerable amount of residual disorder may be retained in the bound form, resulting in a fuzzy complex. Fuzzy regions flanking molecular recognition elements may enable partner fishing through non-specific, transient contacts, thereby facilitating binding, but may also disfavor binding through various mechanisms. So far, few computational or experimental studies have addressed the effect of fuzzy appendages on partner recognition by intrinsically disordered proteins. In order to shed light onto this issue, we used the interaction between the intrinsically disordered C-terminal domain of the measles virus (MeV) nucleoprotein (NTAIL ) and the X domain (XD) of the viral phosphoprotein as model system. After binding to XD, the N-terminal region of NTAIL remains conspicuously disordered, with α-helical folding taking place only within a short molecular recognition element. To study the effect of the N-terminal fuzzy region on NTAIL /XD binding, we generated N-terminal truncation variants of NTAIL , and assessed their binding abilities towards XD. The results revealed that binding increases with shortening of the N-terminal fuzzy region, with this also being observed with hsp70 (another MeV NTAIL binding partner), and for the homologous NTAIL /XD pairs from the Nipah and Hendra viruses. Finally, similar results were obtained when the MeV NTAIL fuzzy region was replaced with a highly dissimilar artificial disordered sequence, supporting a sequence-independent inhibitory effect of the fuzzy region.
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Affiliation(s)
- Antoine Gruet
- Aix-Marseille Université, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France.,Centre National de la Recherche Scientifique, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France
| | - Marion Dosnon
- Aix-Marseille Université, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France.,Centre National de la Recherche Scientifique, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France
| | - David Blocquel
- Aix-Marseille Université, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France.,Centre National de la Recherche Scientifique, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France
| | - Joanna Brunel
- Centre International de Recherche en Infectiologie, INSERM U1111, Centre National de la Recherche Scientifique, UMR 5308, Université Lyon 1, Lyon, France
| | - Denis Gerlier
- Centre International de Recherche en Infectiologie, INSERM U1111, Centre National de la Recherche Scientifique, UMR 5308, Université Lyon 1, Lyon, France
| | - Rahul K Das
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St Louis, MO, USA
| | - Daniela Bonetti
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli' and Istituto di Biologia e Patologia Molecolari del Consiglio Nazionale delle Ricerche, Sapienza Università di Roma, Rome, Italy
| | - Stefano Gianni
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli' and Istituto di Biologia e Patologia Molecolari del Consiglio Nazionale delle Ricerche, Sapienza Università di Roma, Rome, Italy.,Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Monika Fuxreiter
- Hungarian Academy of Sciences, Momentum Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, University of Debrecen, Hungary
| | - Sonia Longhi
- Aix-Marseille Université, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France.,Centre National de la Recherche Scientifique, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France
| | - Christophe Bignon
- Aix-Marseille Université, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France.,Centre National de la Recherche Scientifique, Laboratoire Architecture et Fonction des Macromolécules Biologiques, UMR 7257, Marseille, France
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59
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Plasticity of an ultrafast interaction between nucleoporins and nuclear transport receptors. Cell 2015; 163:734-45. [PMID: 26456112 PMCID: PMC4622936 DOI: 10.1016/j.cell.2015.09.047] [Citation(s) in RCA: 213] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/17/2015] [Accepted: 09/23/2015] [Indexed: 11/23/2022]
Abstract
The mechanisms by which intrinsically disordered proteins engage in rapid and highly selective binding is a subject of considerable interest and represents a central paradigm to nuclear pore complex (NPC) function, where nuclear transport receptors (NTRs) move through the NPC by binding disordered phenylalanine-glycine-rich nucleoporins (FG-Nups). Combining single-molecule fluorescence, molecular simulations, and nuclear magnetic resonance, we show that a rapidly fluctuating FG-Nup populates an ensemble of conformations that are prone to bind NTRs with near diffusion-limited on rates, as shown by stopped-flow kinetic measurements. This is achieved using multiple, minimalistic, low-affinity binding motifs that are in rapid exchange when engaging with the NTR, allowing the FG-Nup to maintain an unexpectedly high plasticity in its bound state. We propose that these exceptional physical characteristics enable a rapid and specific transport mechanism in the physiological context, a notion supported by single molecule in-cell assays on intact NPCs. Integrative structural biology reveals the basis of rapid nuclear transport Transient binding of disordered nucleoporins leaves their plasticity unaffected Multiple minimalistic low-affinity binding motifs create a polyvalent complex A highly reactive and dynamic surface permits an ultrafast binding mechanism
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60
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Tompa P, Schad E, Tantos A, Kalmar L. Intrinsically disordered proteins: emerging interaction specialists. Curr Opin Struct Biol 2015; 35:49-59. [PMID: 26402567 DOI: 10.1016/j.sbi.2015.08.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/23/2015] [Accepted: 08/28/2015] [Indexed: 12/22/2022]
Abstract
Intrinsically disordered proteins or regions of proteins (IDPs/IDRs) most often function through protein-protein interactions, when they permanently or transiently bind partner molecules with diverse functional consequences. There is a rapid advance in our understanding of the ensuing functional modes, obtained from describing atomic details of individual complexes, proteome-wide studies of interactomes and characterizing loosely assembled hydrogels and tightly packed amyloids. Here we briefly survey the most important recent methodological developments and structural-functional observations, with the aim of increasing the general appreciation of IDPs/IDRs as 'interaction specialists'.
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Affiliation(s)
- Peter Tompa
- VIB Structural Biology Research Center (SBRC), Brussels, Belgium; Vrije Universiteit Brussel, Brussels, Belgium; Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary.
| | - Eva Schad
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Agnes Tantos
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Lajos Kalmar
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
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61
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Clark SA, Jespersen N, Woodward C, Barbar E. Multivalent IDP assemblies: Unique properties of LC8-associated, IDP duplex scaffolds. FEBS Lett 2015; 589:2543-51. [PMID: 26226419 DOI: 10.1016/j.febslet.2015.07.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/17/2015] [Accepted: 07/17/2015] [Indexed: 01/17/2023]
Abstract
A wide variety of subcellular complexes are composed of one or more intrinsically disordered proteins (IDPs) that are multivalent, flexible, and characterized by dynamic binding of diverse partner proteins. These multivalent IDP assemblies, of broad functional diversity, are classified here into five categories distinguished by the number of IDP chains and the arrangement of partner proteins in the functional complex. Examples of each category are summarized in the context of the exceptional molecular and biological properties of IDPs. One type - IDP duplex scaffolds - is considered in detail. Its unique features include parallel alignment of two IDP chains, formation of new self-associated domains, enhanced affinity for additional bivalent ligands, and ubiquitous binding of the hub protein LC8. For two IDP duplex scaffolds, dynein intermediate chain IC and nucleoporin Nup159, these duplex features, together with the inherent flexibility of IDPs, are central to their assembly and function. A new type of IDP-LC8 interaction, distributed binding of LC8 among multiple IDP recognition sites, is described for Nup159 assembly.
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Affiliation(s)
- Sarah A Clark
- Department of Biochemistry & Biophysics, Oregon State University, Corvallis, OR 97331, United States
| | - Nathan Jespersen
- Department of Biochemistry & Biophysics, Oregon State University, Corvallis, OR 97331, United States
| | - Clare Woodward
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, St. Paul, MN 55108, United States
| | - Elisar Barbar
- Department of Biochemistry & Biophysics, Oregon State University, Corvallis, OR 97331, United States.
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62
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Conformational propensities of intrinsically disordered proteins influence the mechanism of binding and folding. Proc Natl Acad Sci U S A 2015. [PMID: 26195786 DOI: 10.1073/pnas.1512799112] [Citation(s) in RCA: 188] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) frequently function in protein interaction networks that regulate crucial cellular signaling pathways. Many IDPs undergo transitions from disordered conformational ensembles to folded structures upon binding to their cellular targets. Several possible binding mechanisms for coupled folding and binding have been identified: folding of the IDP after association with the target ("induced fit"), or binding of a prefolded state in the conformational ensemble of the IDP to the target protein ("conformational selection"), or some combination of these two extremes. The interaction of the intrinsically disordered phosphorylated kinase-inducible domain (pKID) of the cAMP-response element binding (CREB) protein with the KIX domain of a general transcriptional coactivator CREB-binding protein (CBP) provides an example of the induced-fit mechanism. Here we show by NMR relaxation dispersion experiments that a different intrinsically disordered ligand, the transactivation domain of the transcription factor c-Myb, interacts with KIX at the same site as pKID but via a different binding mechanism that involves elements of conformational selection and induced fit. In contrast to pKID, the c-Myb activation domain has a strong propensity for spontaneous helix formation in its N-terminal region, which binds to KIX in a predominantly folded conformation. The C-terminal region of c-Myb exhibits a much smaller helical propensity and likely folds via an induced-fit process after binding to KIX. We propose that the intrinsic secondary structure propensities of pKID and c-Myb determine their binding mechanisms, consistent with their functions as inducible and constitutive transcriptional activators.
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63
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Dogan J, Jonasson J, Andersson E, Jemth P. Binding Rate Constants Reveal Distinct Features of Disordered Protein Domains. Biochemistry 2015; 54:4741-50. [DOI: 10.1021/acs.biochem.5b00520] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Jakob Dogan
- Department
of Medical Biochemistry
and Microbiology, Uppsala University, BMC Box 582, SE-75123 Uppsala, Sweden
| | - Josefin Jonasson
- Department
of Medical Biochemistry
and Microbiology, Uppsala University, BMC Box 582, SE-75123 Uppsala, Sweden
| | - Eva Andersson
- Department
of Medical Biochemistry
and Microbiology, Uppsala University, BMC Box 582, SE-75123 Uppsala, Sweden
| | - Per Jemth
- Department
of Medical Biochemistry
and Microbiology, Uppsala University, BMC Box 582, SE-75123 Uppsala, Sweden
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64
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Berlow RB, Dyson HJ, Wright PE. Functional advantages of dynamic protein disorder. FEBS Lett 2015; 589:2433-40. [PMID: 26073260 DOI: 10.1016/j.febslet.2015.06.003] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 11/19/2022]
Abstract
Intrinsically disordered proteins participate in many important cellular regulatory processes. The absence of a well-defined structure in the free state of a disordered domain, and even on occasion when it is bound to physiological partners, is fundamental to its function. Disordered domains are frequently the location of multiple sites for post-translational modification, the key element of metabolic control in the cell. When a disordered domain folds upon binding to a partner, the resulting complex buries a far greater surface area than in an interaction of comparably-sized folded proteins, thus maximizing specificity at modest protein size. Disorder also maintains accessibility of sites for post-translational modification. Because of their inherent plasticity, disordered domains frequently adopt entirely different structures when bound to different partners, increasing the repertoire of available interactions without the necessity for expression of many different proteins. This feature also adds to the faithfulness of cellular regulation, as the availability of a given disordered domain depends on competition between various partners relevant to different cellular processes.
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Affiliation(s)
- Rebecca B Berlow
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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65
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Papadakos G, Sharma A, Lancaster LE, Bowen R, Kaminska R, Leech AP, Walker D, Redfield C, Kleanthous C. Consequences of Inducing Intrinsic Disorder in a High-Affinity Protein–Protein Interaction. J Am Chem Soc 2015; 137:5252-5. [DOI: 10.1021/ja512607r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Grigorios Papadakos
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Amit Sharma
- Astbury
Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Lorna E. Lancaster
- School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, United Kingdom
| | - Rebecca Bowen
- Department of Biology, University of York, Heslington Road, York YO10 5DD, United Kingdom
| | - Renata Kaminska
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Andrew P. Leech
- Department of Biology, University of York, Heslington Road, York YO10 5DD, United Kingdom
| | - Daniel Walker
- Institute
of Infection, Immunity and Inflammation, College of Medical, Veterinary
and Life Sciences, University of Glasgow, Glasgow G12 8AT, United Kingdom
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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66
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Dosnon M, Bonetti D, Morrone A, Erales J, di Silvio E, Longhi S, Gianni S. Demonstration of a folding after binding mechanism in the recognition between the measles virus NTAIL and X domains. ACS Chem Biol 2015; 10:795-802. [PMID: 25511246 DOI: 10.1021/cb5008579] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In the past decade, a wealth of experimental data has demonstrated that a large fraction of proteins, while functional, are intrinsically disordered at physiological conditions. Many intrinsically disordered proteins (IDPs) undergo a disorder-to-order transition upon binding to their biological targets, a phenomenon known as induced folding. Induced folding may occur through two extreme mechanisms, namely conformational selection and folding after binding. Although the pre-existence of ordered structures in IDPs is a prerequisite for conformational selection, it does not necessarily commit to this latter mechanism, and kinetic studies are needed to discriminate between the two possible scenarios. So far, relatively few studies have addressed this issue from an experimental perspective. Here, we analyze the interaction kinetics between the intrinsically disordered C-terminal domain of the measles virus nucleoprotein (NTAIL) and the X domain (XD) of the viral phosphoprotein. Data reveal that NTAIL recognizes XD by first forming a weak encounter complex in a disordered conformation, which is subsequently locked-in by a folding step; i.e., binding precedes folding. The implications of our kinetic results, in the context of previously reported equilibrium data, are discussed. These results contribute to enhancing our understanding of the molecular mechanisms by which IDPs recognize their partners and represent a paradigmatic example of the need of kinetic methods to discriminate between reaction mechanisms.
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Affiliation(s)
- Marion Dosnon
- Aix-Marseille Université, Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257, 13288, Marseille, France
- CNRS, AFMB UMR 7257, 13288, Marseille, France
| | - 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
| | - Angela Morrone
- 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
| | - Jenny Erales
- Aix-Marseille Université, Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257, 13288, Marseille, France
- CNRS, AFMB UMR 7257, 13288, Marseille, France
| | - Eva di Silvio
- 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
| | - Sonia Longhi
- Aix-Marseille Université, Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257, 13288, Marseille, France
- CNRS, AFMB UMR 7257, 13288, 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
- Department
of Chemistry, University of Cambridge, Cambridge CB21EW, United Kingdom
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67
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Abstract
Intrinsically disordered proteins (IDPs) are important components of the cellular signalling machinery, allowing the same polypeptide to undertake different interactions with different consequences. IDPs are subject to combinatorial post-translational modifications and alternative splicing, adding complexity to regulatory networks and providing a mechanism for tissue-specific signalling. These proteins participate in the assembly of signalling complexes and in the dynamic self-assembly of membrane-less nuclear and cytoplasmic organelles. Experimental, computational and bioinformatic analyses combine to identify and characterize disordered regions of proteins, leading to a greater appreciation of their widespread roles in biological processes.
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68
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DeForte S, Reddy KD, Uversky VN. Digested disorder, Quarterly intrinsic disorder digest (October-November-December, 2013). INTRINSICALLY DISORDERED PROTEINS 2015; 3:e984569. [PMID: 28293487 DOI: 10.4161/21690707.2014.984569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 11/19/2022]
Abstract
This is the 4th issue of the Digested Disorder series that represents reader's digest of the scientific literature on intrinsically disordered proteins. The only 2 criteria for inclusion in this digest are the publication date (a paper should be published within the covered time frame) and topic (a paper should be dedicated to any aspect of protein intrinsic disorder). The current digest issue covers papers published during the fourth quarter of 2013; i.e. during the period of October, November, and December of 2013. Similar to previous issues, the papers are grouped hierarchically by topics they cover, and for each of the included paper a short description is given on its major findings.
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Affiliation(s)
- Shelly DeForte
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; These authors contributed equally to this work
| | - Krishna D Reddy
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; These authors contributed equally to this work
| | - Vladimir N Uversky
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa, FL USA; USF Health Byrd Alzheimer Research Institute; Morsani College of Medicine; University of South Florida; Tampa, FL USA; Biology Department; Faculty of Science; King Abdulaziz University; Jeddah, Kingdom of Saudi Arabia; Laboratory of Structural Dynamics, Stability, and Folding of Proteins; Institute of Cytology; Russian Academy of Sciences; St. Petersburg, Russia; Institute for Biological Instrumentation; Russian Academy of Sciences; Moscow Region, Russia
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69
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Gianni S, Dogan J, Jemth P. Deciphering the mechanisms of binding induced folding at nearly atomic resolution: The Φ value analysis applied to IDPs. INTRINSICALLY DISORDERED PROTEINS 2014; 2:e970900. [PMID: 28232881 PMCID: PMC5314873 DOI: 10.4161/idp.28624] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 03/18/2014] [Accepted: 03/21/2014] [Indexed: 11/24/2022]
Abstract
The Φ value analysis is a method to analyze the structure of metastable states in reaction pathways. Such a methodology is based on the quantitative analysis of the effect of point mutations on the kinetics and thermodynamics of the probed reaction. The Φ value analysis is routinely used in protein folding studies and is potentially an extremely powerful tool to analyze the mechanism of binding induced folding of intrinsically disordered proteins. In this review we recapitulate the key equations and experimental advices to perform the Φ value analysis in the perspective of the possible caveats arising in intrinsically disordered systems. Finally, we briefly discuss some few examples already available in the literature.
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Affiliation(s)
- Stefano Gianni
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli"; Istituto di Biologia e Patologia Molecolari del CNR; Università di Roma "La Spaienza"; Rome, Italy; Department of Chemistry; University of Cambridge; Cambridge, UK
| | - Jakob Dogan
- Department of Medical Biochemistry and Microbiology; Uppsala University ; Uppsala, Sweden
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology; Uppsala University ; Uppsala, Sweden
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70
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Rogers JM, Oleinikovas V, Shammas SL, Wong CT, De Sancho D, Baker CM, Clarke J. Interplay between partner and ligand facilitates the folding and binding of an intrinsically disordered protein. Proc Natl Acad Sci U S A 2014; 111:15420-5. [PMID: 25313042 PMCID: PMC4217413 DOI: 10.1073/pnas.1409122111] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein-protein interactions are at the heart of regulatory and signaling processes in the cell. In many interactions, one or both proteins are disordered before association. However, this disorder in the unbound state does not prevent many of these proteins folding to a well-defined, ordered structure in the bound state. Here we examine a typical system, where a small disordered protein (PUMA, p53 upregulated modulator of apoptosis) folds to an α-helix when bound to a groove on the surface of a folded protein (MCL-1, induced myeloid leukemia cell differentiation protein). We follow the association of these proteins using rapid-mixing stopped flow, and examine how the kinetic behavior is perturbed by denaturant and carefully chosen mutations. We demonstrate the utility of methods developed for the study of monomeric protein folding, including β-Tanford values, Leffler α, Φ-value analysis, and coarse-grained simulations, and propose a self-consistent mechanism for binding. Folding of the disordered protein before binding does not appear to be required and few, if any, specific interactions are required to commit to association. The majority of PUMA folding occurs after the transition state, in the presence of MCL-1. We also examine the role of the side chains of folded MCL-1 that make up the binding groove and find that many favor equilibrium binding but, surprisingly, inhibit the association process.
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Affiliation(s)
- Joseph M Rogers
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | | | - Sarah L Shammas
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Chi T Wong
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - David De Sancho
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Christopher M Baker
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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71
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Allostery within a transcription coactivator is predominantly mediated through dissociation rate constants. Proc Natl Acad Sci U S A 2014; 111:12055-60. [PMID: 25092343 DOI: 10.1073/pnas.1405815111] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinase-inducible domain interacting (KIX) domain of CREB binding protein binds to multiple intrinsically disordered transcription factors in vivo at two distinct sites on its surface. Several reports have been made of allosteric communication between these two sites in this well-characterized model system. In this work, we have performed fluorescence stopped-flow measurements to investigate the kinetics of binding of five KIX binding proteins. We find that they all have similar association and dissociation rate constants for complex formation, despite their wide range of intrinsic helical propensities. Furthermore, by careful arrangement of pseudofirst-order conditions, we have been able to show that both association and dissociation rate constants are decreased when a partner is bound at the alternative site. These decreases suggest that positive allosteric effects are not mediated by structural changes in binding sites but rather, through a more general mechanism, largely mediated through dissociation, which we propose is largely related to changes in the flexibility of the KIX domain itself.
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72
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Dissecting allosteric effects of activator-coactivator complexes using a covalent small molecule ligand. Proc Natl Acad Sci U S A 2014; 111:12061-6. [PMID: 25049401 DOI: 10.1073/pnas.1406033111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Allosteric binding events play a critical role in the formation and stability of transcriptional activator-coactivator complexes, perhaps in part due to the often intrinsically disordered nature of one or more of the constituent partners. The kinase-inducible domain interacting (KIX) domain of the master coactivator CREB binding protein/p300 is a conformationally dynamic domain that complexes with transcriptional activators at two discrete binding sites in allosteric communication. The complexation of KIX with the transcriptional activation domain of mixed-lineage leukemia protein leads to an enhancement of binding by the activation domain of CREB (phosphorylated kinase-inducible domain of CREB) to the second site. A transient kinetic analysis of the ternary complex formation aided by small molecule ligands that induce positive or negative cooperative binding reveals that positive cooperativity is largely governed by stabilization of the bound complex as indicated by a decrease in koff. Thus, this suggests the increased binding affinity for the second ligand is not due to an allosteric creation of a more favorable binding interface by the first ligand. This is consistent with data from us and from others indicating that the on rates of conformationally dynamic proteins approach the limits of diffusion. In contrast, negative cooperativity is manifested by alterations in both kon and koff, suggesting stabilization of the binary complex.
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73
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Affiliation(s)
- Johnny Habchi
- Aix-Marseille Université , Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257, 13288, Marseille, France
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74
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Abstract
The kinase-inducible domain interacting (KIX) domain of the CREB binding protein (CBP) is capable of simultaneously binding two intrinsically disordered transcription factors, such as the mixed-lineage leukemia (MLL) and c-Myb peptides, at isolated interaction sites. In vitro, the affinity for binding c-Myb is approximately doubled when KIX is in complex with MLL, which suggests a positive cooperative binding mechanism, and the affinity for MLL is also slightly increased when KIX is first bound by c-Myb. Expanding the scope of recent NMR and computational studies, we explore the allosteric mechanism at a detailed molecular level that directly connects the microscopic structural dynamics to the macroscopic shift in binding affinities. To this end, we have performed molecular dynamics simulations of free KIX, KIX-c-Myb, MLL-KIX, and MLL-KIX-c-Myb using a topology-based Gō-like model. Our results capture an increase in affinity for the peptide in the allosteric site when KIX is prebound by a complementary effector and both peptides follow an effector-independent folding-and-binding mechanism. More importantly, we discover that MLL binding lowers the entropic cost for c-Myb binding, and vice versa, by stabilizing the L12-G2 loop and the C-terminal region of the α3 helix on KIX. This work demonstrates the importance of entropy in allosteric signaling between promiscuous molecular recognition sites and can inform the rational design of small molecule stabilizers to target important regions of conformationally dynamic proteins.
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75
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Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
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76
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Rogers J, Wong CT, Clarke J. Coupled folding and binding of the disordered protein PUMA does not require particular residual structure. J Am Chem Soc 2014; 136:5197-200. [PMID: 24654952 PMCID: PMC4017604 DOI: 10.1021/ja4125065] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Indexed: 11/29/2022]
Abstract
Many cellular proteins are 'disordered' in isolation. A subset of these intrinsically disordered proteins (IDPs) can, upon binding another molecule, fold to a well-defined three-dimensional structure. In the structurally heterogeneous, unbound ensemble of these IDPs, conformations are likely to exist that, in part, resemble the final bound form. It has been suggested that these conformations, displaying 'residual structure', could be important for the mechanism of such coupled folding and binding reactions. PUMA, of the BCL-2 family, is an IDP in isolation but will form a single, contiguous α-helix upon binding the folded protein MCL-1. Using the helix-breaking residue proline, we systematically target each potential turn of helix of unbound PUMA and assess the binding to MCL-1 using time-resolved stopped-flow techniques. All proline-containing mutants bound, and although binding was weaker than the wild-type protein, association rate constants were largely unaffected. We conclude that population of particular residual structure, containing a specific helical turn, is neither required for the binding nor for fast association of PUMA and MCL-1.
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Affiliation(s)
- Joseph
M. Rogers
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Chi T. Wong
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
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77
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Abstract
Intrinsically disordered proteins (IDPs) and IDP regions fail to form a stable structure, yet they exhibit biological activities. Their mobile flexibility and structural instability are encoded by their amino acid sequences. They recognize proteins, nucleic acids, and other types of partners; they accelerate interactions and chemical reactions between bound partners; and they help accommodate posttranslational modifications, alternative splicing, protein fusions, and insertions or deletions. Overall, IDP-associated biological activities complement those of structured proteins. Recently, there has been an explosion of studies on IDP regions and their functions, yet the discovery and investigation of these proteins have a long, mostly ignored history. Along with recent discoveries, we present several early examples and the mechanisms by which IDPs contribute to function, which we hope will encourage comprehensive discussion of IDPs and IDP regions in biochemistry textbooks. Finally, we propose future directions for IDP research.
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Affiliation(s)
- Christopher J Oldfield
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana 46202; ,
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78
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Dogan J, Gianni S, Jemth P. The binding mechanisms of intrinsically disordered proteins. Phys Chem Chem Phys 2013; 16:6323-31. [PMID: 24317797 DOI: 10.1039/c3cp54226b] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) of proteins are very common and instrumental for cellular signaling. Recently, a number of studies have investigated the kinetic binding mechanisms of IDPs and IDRs. These results allow us to draw conclusions about the energy landscape for the coupled binding and folding of disordered proteins. The association rate constants of IDPs cover a wide range (10(5)-10(9) M(-1) s(-1)) and are largely governed by long-range charge-charge interactions, similarly to interactions between well-folded proteins. Off-rate constants also differ significantly among IDPs (with half-lives of up to several minutes) but are usually around 0.1-1000 s(-1), allowing for rapid dissociation of complexes. Likewise, affinities span from pM to μM suggesting that the low-affinity high-specificity concept for IDPs is not straightforward. Overall, it appears that binding precedes global folding although secondary structure elements such as helices may form before the protein-protein interaction. Short IDPs bind in apparent two-state reactions whereas larger IDPs often display complex multi-step binding reactions. While the two extreme cases of two-step binding (conformational selection and induced fit) or their combination into a square mechanism is an attractive model in theory, it is too simplistic in practice. Experiment and simulation suggest a more complex energy landscape in which IDPs bind targets through a combination of conformational selection before binding (e.g., secondary structure formation) and induced fit after binding (global folding and formation of short-range intermolecular interactions).
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Affiliation(s)
- Jakob Dogan
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, SE-75123 Uppsala, Sweden.
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