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Chinellato M, Perin S, Carli A, Lastella L, Biondi B, Borsato G, Di Giorgio E, Brancolini C, Cendron L, Angelini A. Folding of Class IIa HDAC Derived Peptides into α-helices Upon Binding to Myocyte Enhancer Factor-2 in Complex with DNA. J Mol Biol 2024; 436:168541. [PMID: 38492719 DOI: 10.1016/j.jmb.2024.168541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 02/27/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024]
Abstract
Interaction of transcription factor myocyte enhancer factor-2 (MEF2) family members with class IIa histone deacetylases (HDACs) has been implicated in a wide variety of diseases. Though considerable knowledge on this topic has been accumulated over the years, a high resolution and detailed analysis of the binding mode of multiple class IIa HDAC derived peptides with MEF2D is still lacking. To fulfil this gap, we report here the crystal structure of MEF2D in complex with double strand DNA and four different class IIa HDAC derived peptides, namely HDAC4, HDAC5, HDAC7 and HDAC9. All class IIa HDAC derived peptides form extended amphipathic α-helix structures that fit snugly in the hydrophobic groove of MEF2D domain. Binding mode of class IIa HDAC derived peptides to MEF2D is very similar and occur primarily through nonpolar interactions mediated by highly conserved branched hydrophobic amino acids. Further studies revealed that class IIa HDAC derived peptides are unstructured in solution and appear to adopt a folded α-helix structure only upon binding to MEF2D. Comparison of our peptide-protein complexes with previously characterized structures of MEF2 bound to different co-activators and co-repressors, highlighted both differences and similarities, and revealed the adaptability of MEF2 in protein-protein interactions. The elucidation of the three-dimensional structure of MEF2D in complex with multiple class IIa HDAC derived peptides provide not only a better understanding of the molecular basis of their interactions but also have implications for the development of novel antagonist.
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Affiliation(s)
- Monica Chinellato
- Department of Biology, University of Padua, Via U. Bassi 58, 35131 Padova, Italy
| | - Stefano Perin
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172 Mestre, Italy
| | - Alberto Carli
- Department of Biology, University of Padua, Via U. Bassi 58, 35131 Padova, Italy
| | - Luana Lastella
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Via Marzolo 1, 35131 Padova, Italy
| | - Barbara Biondi
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Via Marzolo 1, 35131 Padova, Italy
| | - Giuseppe Borsato
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172 Mestre, Italy
| | - Eros Di Giorgio
- Department of Medicine, Università Degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy
| | - Claudio Brancolini
- Department of Medicine, Università Degli Studi di Udine, P.le Kolbe 4, 33100 Udine, Italy
| | - Laura Cendron
- Department of Biology, University of Padua, Via U. Bassi 58, 35131 Padova, Italy.
| | - Alessandro Angelini
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172 Mestre, Italy; European Centre for Living Technology (ECLT), Ca' Bottacin, Dorsoduro 3911, Calle Crosera, 30123 Venice, Italy.
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2
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Hadži S, Živič Z, Kovačič M, Zavrtanik U, Haesaerts S, Charlier D, Plavec J, Volkov AN, Lah J, Loris R. Fuzzy recognition by the prokaryotic transcription factor HigA2 from Vibrio cholerae. Nat Commun 2024; 15:3105. [PMID: 38600130 PMCID: PMC11006873 DOI: 10.1038/s41467-024-47296-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 03/22/2024] [Indexed: 04/12/2024] Open
Abstract
Disordered protein sequences can exhibit different binding modes, ranging from well-ordered folding-upon-binding to highly dynamic fuzzy binding. The primary function of the intrinsically disordered region of the antitoxin HigA2 from Vibrio cholerae is to neutralize HigB2 toxin through ultra-high-affinity folding-upon-binding interaction. Here, we show that the same intrinsically disordered region can also mediate fuzzy interactions with its operator DNA and, through interplay with the folded helix-turn-helix domain, regulates transcription from the higBA2 operon. NMR, SAXS, ITC and in vivo experiments converge towards a consistent picture where a specific set of residues in the intrinsically disordered region mediate electrostatic and hydrophobic interactions while "hovering" over the DNA operator. Sensitivity of the intrinsically disordered region to scrambling the sequence, position-specific contacts and absence of redundant, multivalent interactions, point towards a more specific type of fuzzy binding. Our work demonstrates how a bacterial regulator achieves dual functionality by utilizing two distinct interaction modes within the same disordered sequence.
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Affiliation(s)
- San Hadži
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Centre for Structural Biology, VIB, Pleinlaan 2, 1050, Brussels, Belgium
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Zala Živič
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Matic Kovačič
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova, 19, 1000, Ljubljana, Slovenia
| | - Uroš Zavrtanik
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Sarah Haesaerts
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Centre for Structural Biology, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Daniel Charlier
- Research group of Microbiology, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova, 19, 1000, Ljubljana, Slovenia
| | - Alexander N Volkov
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
- Centre for Structural Biology, VIB, Pleinlaan 2, 1050, Brussels, Belgium
- Jean Jeener NMR Centre, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
| | - Jurij Lah
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia.
| | - Remy Loris
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
- Centre for Structural Biology, VIB, Pleinlaan 2, 1050, Brussels, Belgium.
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3
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Ren X, Cui Z, Zhang Q, Su Z, Xu W, Wu J, Jiang H. JunB condensation attenuates vascular endothelial damage under hyperglycemic condition. J Mol Cell Biol 2024; 15:mjad072. [PMID: 38140943 PMCID: PMC11080659 DOI: 10.1093/jmcb/mjad072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 09/23/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Endothelial damage is the initial and crucial factor in the occurrence and development of vascular complications in diabetic patients, contributing to morbidity and mortality. Although hyperglycemia has been identified as a damaging effector, the detailed mechanisms remain elusive. In this study, identified by ATAC-seq and RNA-seq, JunB reverses the inhibition of proliferation and the promotion of apoptosis in human umbilical vein endothelial cells treated with high glucose, mainly through the cell cycle and p53 signaling pathways. Furthermore, JunB undergoes phase separation in the nucleus and in vitro, mediated by its intrinsic disordered region and DNA-binding domain. Nuclear localization and condensation behaviors are required for JunB-mediated proliferation and apoptosis. Thus, our study uncovers the roles of JunB and its coacervation in repairing vascular endothelial damage caused by high glucose, elucidating the involvement of phase separation in diabetes and diabetic endothelial dysfunction.
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Affiliation(s)
- Xuxia Ren
- Laboratory for Aging and Cancer Research, Frontiers Science Center Disease-related Molecular Network, State Key Laboratory of Respiratory Health and Multimorbidity and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zexu Cui
- Laboratory for Aging and Cancer Research, Frontiers Science Center Disease-related Molecular Network, State Key Laboratory of Respiratory Health and Multimorbidity and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qiaoqiao Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhiguang Su
- Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Wei Xu
- Laboratory for Aging and Cancer Research, Frontiers Science Center Disease-related Molecular Network, State Key Laboratory of Respiratory Health and Multimorbidity and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jinhui Wu
- Center of Geriatrics and Gerontology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Hao Jiang
- Laboratory for Aging and Cancer Research, Frontiers Science Center Disease-related Molecular Network, State Key Laboratory of Respiratory Health and Multimorbidity and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
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4
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Kumar A, Madhurima K, Naganathan AN, Vallurupalli P, Sekhar A. Probing excited state 1Hα chemical shifts in intrinsically disordered proteins with a triple resonance-based CEST experiment: Application to a disorder-to-order switch. Methods 2023; 218:198-209. [PMID: 37607621 PMCID: PMC7615522 DOI: 10.1016/j.ymeth.2023.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 08/24/2023] Open
Abstract
Over 40% of eukaryotic proteomes and 15% of bacterial proteomes are predicted to be intrinsically disordered based on their amino acid sequence. Intrinsically disordered proteins (IDPs) exist as heterogeneous ensembles of interconverting conformations and pose a challenge to the structure-function paradigm by apparently functioning without possessing stable structural elements. IDPs play a prominent role in biological processes involving extensive intermolecular interaction networks and their inherently dynamic nature facilitates their promiscuous interaction with multiple structurally diverse partner molecules. NMR spectroscopy has made pivotal contributions to our understanding of IDPs because of its unique ability to characterize heterogeneity at atomic resolution. NMR methods such as Chemical Exchange Saturation Transfer (CEST) and relaxation dispersion have enabled the detection of 'invisible' excited states in biomolecules which are transiently and sparsely populated, yet central for function. Here, we develop a 1Hα CEST pulse sequence which overcomes the resonance overlap problem in the 1Hα-13Cα plane of IDPs by taking advantage of the superior resolution in the 1H-15N correlation spectrum. In this sequence, magnetization is transferred after 1H CEST using a triple resonance coherence transfer pathway from 1Hα (i) to 1HN(i + 1) during which the 15N(t1) and 1HN(t2) are frequency labelled. This approach is integrated with spin state-selective CEST for eliminating spurious dips in CEST profiles resulting from dipolar cross-relaxation. We apply this sequence to determine the excited state 1Hα chemical shifts of the intrinsically disordered DNA binding domain (CytRN) of the bacterial cytidine repressor (CytR), which transiently acquires a functional globally folded conformation. The structure of the excited state, calculated using 1Hα chemical shifts in conjunction with other excited state NMR restraints, is a three-helix bundle incorporating a helix-turn-helix motif that is vital for binding DNA.
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Affiliation(s)
- Ajith Kumar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Kulkarni Madhurima
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Athi N Naganathan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Pramodh Vallurupalli
- Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad 500046, India
| | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India.
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5
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Oda M. Analysis of the Structural Dynamics of Proteins in the Ligand-Unbound and -Bound States by Diffracted X-ray Tracking. Int J Mol Sci 2023; 24:13717. [PMID: 37762021 PMCID: PMC10531450 DOI: 10.3390/ijms241813717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Although many protein structures have been determined at atomic resolution, the majority of them are static and represent only the most stable or averaged structures in solution. When a protein binds to its ligand, it usually undergoes fluctuation and changes its conformation. One attractive method for obtaining an accurate view of proteins in solution, which is required for applications such as the rational design of proteins and structure-based drug design, is diffracted X-ray tracking (DXT). DXT can detect the protein structural dynamics on a timeline via gold nanocrystals attached to the protein. Here, the structure dynamics of single-chain Fv antibodies, helix bundle-forming de novo designed proteins, and DNA-binding proteins in both ligand-unbound and ligand-bound states were analyzed using the DXT method. The resultant mean square angular displacements (MSD) curves in both the tilting and twisting directions clearly demonstrated that structural fluctuations were suppressed upon ligand binding, and the binding energies determined using the angular diffusion coefficients from the MSD agreed well with the binding thermodynamics determined using isothermal titration calorimetry. In addition, the size of gold nanocrystals is discussed, which is one of the technical concerns of DXT.
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Affiliation(s)
- Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
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Manyilov VD, Ilyinsky NS, Nesterov SV, Saqr BMGA, Dayhoff GW, Zinovev EV, Matrenok SS, Fonin AV, Kuznetsova IM, Turoverov KK, Ivanovich V, Uversky VN. Chaotic aging: intrinsically disordered proteins in aging-related processes. Cell Mol Life Sci 2023; 80:269. [PMID: 37634152 PMCID: PMC11073068 DOI: 10.1007/s00018-023-04897-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/03/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023]
Abstract
The development of aging is associated with the disruption of key cellular processes manifested as well-established hallmarks of aging. Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) have no stable tertiary structure that provide them a power to be configurable hubs in signaling cascades and regulate many processes, potentially including those related to aging. There is a need to clarify the roles of IDPs/IDRs in aging. The dataset of 1702 aging-related proteins was collected from established aging databases and experimental studies. There is a noticeable presence of IDPs/IDRs, accounting for about 36% of the aging-related dataset, which is however less than the disorder content of the whole human proteome (about 40%). A Gene Ontology analysis of the used here aging proteome reveals an abundance of IDPs/IDRs in one-third of aging-associated processes, especially in genome regulation. Signaling pathways associated with aging also contain IDPs/IDRs on different hierarchical levels, revealing the importance of "structure-function continuum" in aging. Protein-protein interaction network analysis showed that IDPs present in different clusters associated with different aging hallmarks. Protein cluster with IDPs enrichment has simultaneously high liquid-liquid phase separation (LLPS) probability, "nuclear" localization and DNA-associated functions, related to aging hallmarks: genomic instability, telomere attrition, epigenetic alterations, and stem cells exhaustion. Intrinsic disorder, LLPS, and aggregation propensity should be considered as features that could be markers of pathogenic proteins. Overall, our analyses indicate that IDPs/IDRs play significant roles in aging-associated processes, particularly in the regulation of DNA functioning. IDP aggregation, which can lead to loss of function and toxicity, could be critically harmful to the cell. A structure-based analysis of aging and the identification of proteins that are particularly susceptible to disturbances can enhance our understanding of the molecular mechanisms of aging and open up new avenues for slowing it down.
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Affiliation(s)
- Vladimir D Manyilov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
| | - Nikolay S Ilyinsky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia.
| | - Semen V Nesterov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia
| | - Baraa M G A Saqr
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
| | - Guy W Dayhoff
- Department of Chemistry, University of South Florida, Tampa, FL, USA
| | - Egor V Zinovev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
| | - Simon S Matrenok
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
| | - Alexander V Fonin
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia
| | - Irina M Kuznetsova
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia
| | | | - Valentin Ivanovich
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia
| | - Vladimir N Uversky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy Pereulok, 9, Dolgoprudny, 141700, Russia.
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., MDC07, Tampa, FL, 33612, USA.
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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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Danchin A. Biological innovation in the functional landscape of a model regulator, or the lactose operon repressor. C R Biol 2021; 344:111-126. [PMID: 34213850 DOI: 10.5802/crbiol.52] [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] [Received: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 12/24/2022]
Abstract
The operon model was proposed six decades ago. And yet, despite all this time, the lactose operon repressor, LacI, remains a subject of major interest. While it is well established that LacI can exist in two functional forms, one that renders the operon inactive via binding of LacI to DNA and another, bound to an inducer that does not allow repression, how it switches from one to the other is still not well understood. The construction of a library of several tens of thousands of LacI mutants has revealed some unexpected features. In particular, the transition implemented in some of them reveals a new type of transcription regulation: band-pass (OFF/ON/OFF) and band-stop (ON/OFF/ON) filters. This makes it natural to think that it is the network of hydrogen bonds associated with the water bound to the molecule that allows the remote interconnection between the binding site to an inducer molecule and the one that binds it to the DNA.
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Affiliation(s)
- Antoine Danchin
- Kodikos Labs, Institut Cochin, 24 rue du Faubourg Saint-Jacques 75014 Paris, France
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9
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Kawasaki M, Oda M. DNA-binding function of c-Myb R2R3 around thermal denaturation temperature. Biophys Physicobiol 2021; 18:78-84. [PMID: 33977005 PMCID: PMC8056152 DOI: 10.2142/biophysico.bppb-v18.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/22/2021] [Indexed: 01/23/2023] Open
Abstract
The minimum DNA-binding domain of the transcriptional factor c-Myb R2R3 remarkably fluctuates in the solution. In the present study, we evaluated the protein fluctuation of R2R3 C130I mutant, R2R3*, on its DNA-binding and folding thermodynamics. DNA-binding analysis using isothermal titration calorimetry revealed that the heat capacity change determined from the correlation between temperature and binding enthalpy change is highly negative above 35°C, indicating that the fluctuation increases with increasing temperature and elevates the conformational change on DNA binding. The results were in accordance with those of differential scanning calorimetry, which revealed that the heat capacity corresponding to thermal denaturation gradually increased above 35°C, followed by the broad transition peak. In contrast, the transition peak of R2R3* in the DNA-bound state was sharper and larger than that in the DNA-unbound state. The fluctuating form could transform into lesser fluctuating form upon DNA binding, resulting in a larger enthalpy change for denaturation of R2R3* in the DNA-bound state. It should also be noted that R2R3* could specifically bind to DNA around thermal denaturation temperature. This would be due to proteins with numerous fluctuations. Moreover, we discuss specific and non-specific DNA binding accompanied by the conformational change between well-ordered and disordered forms of R2R3* observed around the denaturation temperature.
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Affiliation(s)
- Maki Kawasaki
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan
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