1
|
King MR, Ruff KM, Pappu RV. Emergent microenvironments of nucleoli. Nucleus 2024; 15:2319957. [PMID: 38443761 PMCID: PMC10936679 DOI: 10.1080/19491034.2024.2319957] [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: 09/04/2023] [Accepted: 02/13/2024] [Indexed: 03/07/2024] Open
Abstract
In higher eukaryotes, the nucleolus harbors at least three sub-phases that facilitate multiple functionalities including ribosome biogenesis. The three prominent coexisting sub-phases are the fibrillar center (FC), the dense fibrillar component (DFC), and the granular component (GC). Here, we review recent efforts in profiling sub-phase compositions that shed light on the types of physicochemical properties that emerge from compositional biases and territorial organization of specific types of macromolecules. We highlight roles played by molecular grammars which refers to protein sequence features including the substrate binding domains, the sequence features of intrinsically disordered regions, and the multivalence of these distinct types of domains / regions. We introduce the concept of a barcode of emergent physicochemical properties of nucleoli. Although our knowledge of the full barcode remains incomplete, we hope that the concept prompts investigations into undiscovered emergent properties and engenders an appreciation for how and why unique microenvironments control biochemical reactions.
Collapse
Affiliation(s)
- Matthew R. King
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Campus, MO, USA
| | - Kiersten M. Ruff
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Campus, MO, USA
| | - Rohit V. Pappu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Campus, MO, USA
| |
Collapse
|
2
|
Zhang G, Chu X. Balancing thermodynamic stability, dynamics, and kinetics in phase separation of intrinsically disordered proteins. J Chem Phys 2024; 161:095102. [PMID: 39225535 DOI: 10.1063/5.0220861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/25/2024] [Indexed: 09/04/2024] Open
Abstract
Intrinsically disordered proteins (IDPs) are prevalent participants in liquid-liquid phase separation due to their inherent potential for promoting multivalent binding. Understanding the underlying mechanisms of phase separation is challenging, as phase separation is a complex process, involving numerous molecules and various types of interactions. Here, we used a simplified coarse-grained model of IDPs to investigate the thermodynamic stability of the dense phase, conformational properties of IDPs, chain dynamics, and kinetic rates of forming condensates. We focused on the IDP system, in which the oppositely charged IDPs are maximally segregated, inherently possessing a high propensity for phase separation. By varying interaction strengths, salt concentrations, and temperatures, we observed that IDPs in the dense phase exhibited highly conserved conformational characteristics, which are more extended than those in the dilute phase. Although the chain motions and global conformational dynamics of IDPs in the condensates are slow due to the high viscosity, local chain flexibility at the short timescales is largely preserved with respect to that at the free state. Strikingly, we observed a non-monotonic relationship between interaction strengths and kinetic rates for forming condensates. As strong interactions of IDPs result in high stable condensates, our results suggest that the thermodynamics and kinetics of phase separation are decoupled and optimized by the speed-stability balance through underlying molecular interactions. Our findings contribute to the molecular-level understanding of phase separation and offer valuable insights into the developments of engineering strategies for precise regulation of biomolecular condensates.
Collapse
Affiliation(s)
- Guoqing Zhang
- Advanced Materials Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, Guangdong 511400, China
| | - Xiakun Chu
- Advanced Materials Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, Guangdong 511400, China
- Guangzhou Municipal Key Laboratory of Materials Informatics, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, Guangdong 511400, China
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR 999077, China
| |
Collapse
|
3
|
Dai Y, Zhou Z, Yu W, Ma Y, Kim K, Rivera N, Mohammed J, Lantelme E, Hsu-Kim H, Chilkoti A, You L. Biomolecular condensates regulate cellular electrochemical equilibria. Cell 2024:S0092-8674(24)00909-7. [PMID: 39260373 DOI: 10.1016/j.cell.2024.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 05/22/2024] [Accepted: 08/09/2024] [Indexed: 09/13/2024]
Abstract
Control of the electrochemical environment in living cells is typically attributed to ion channels. Here, we show that the formation of biomolecular condensates can modulate the electrochemical environment in bacterial cells, which affects cellular processes globally. Condensate formation generates an electric potential gradient, which directly affects the electrochemical properties of a cell, including cytoplasmic pH and membrane potential. Condensate formation also amplifies cell-cell variability of their electrochemical properties due to passive environmental effect. The modulation of the electrochemical equilibria further controls cell-environment interactions, thus directly influencing bacterial survival under antibiotic stress. The condensate-mediated shift in intracellular electrochemical equilibria drives a change of the global gene expression profile. Our work reveals the biochemical functions of condensates, which extend beyond the functions of biomolecules driving and participating in condensate formation, and uncovers a role of condensates in regulating global cellular physiology.
Collapse
Affiliation(s)
- Yifan Dai
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Saint Louis, MO 63130, USA
| | - Zhengqing Zhou
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Wen Yu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Saint Louis, MO 63130, USA
| | - Yuefeng Ma
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, Saint Louis, MO 63130, USA
| | - Kyeri Kim
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Nelson Rivera
- Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708, USA
| | - Javid Mohammed
- Department of Immunology, Duke University, Durham, NC 27705, USA
| | - Erica Lantelme
- Department of Pathology and Immunology, Washington University in St. Louis, Saint Louis, MO 63110, USA
| | - Heileen Hsu-Kim
- Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708, USA
| | - Ashutosh Chilkoti
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; Department of Immunology, Duke University, Durham, NC 27705, USA.
| | - Lingchong You
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; Department of Immunology, Duke University, Durham, NC 27705, USA; Center for Quantitative Biodesign, Duke University, Durham, NC 27708, USA; Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
| |
Collapse
|
4
|
Steffen FD, Cunha RA, Sigel RKO, Börner R. FRET-guided modeling of nucleic acids. Nucleic Acids Res 2024; 52:e59. [PMID: 38869063 PMCID: PMC11260485 DOI: 10.1093/nar/gkae496] [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: 06/27/2023] [Accepted: 05/29/2024] [Indexed: 06/14/2024] Open
Abstract
The functional diversity of RNAs is encoded in their innate conformational heterogeneity. The combination of single-molecule spectroscopy and computational modeling offers new attractive opportunities to map structural transitions within nucleic acid ensembles. Here, we describe a framework to harmonize single-molecule Förster resonance energy transfer (FRET) measurements with molecular dynamics simulations and de novo structure prediction. Using either all-atom or implicit fluorophore modeling, we recreate FRET experiments in silico, visualize the underlying structural dynamics and quantify the reaction coordinates. Using multiple accessible-contact volumes as a post hoc scoring method for fragment assembly in Rosetta, we demonstrate that FRET can be used to filter a de novo RNA structure prediction ensemble by refuting models that are not compatible with in vitro FRET measurement. We benchmark our FRET-assisted modeling approach on double-labeled DNA strands and validate it against an intrinsically dynamic manganese(II)-binding riboswitch. We show that a FRET coordinate describing the assembly of a four-way junction allows our pipeline to recapitulate the global fold of the riboswitch displayed by the crystal structure. We conclude that computational fluorescence spectroscopy facilitates the interpretability of dynamic structural ensembles and improves the mechanistic understanding of nucleic acid interactions.
Collapse
Affiliation(s)
- Fabio D Steffen
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Richard A Cunha
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Richard Börner
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| |
Collapse
|
5
|
Shukla S, Bhattacharya A, Sehrawat P, Agarwal P, Shobhawat R, Malik N, Duraisamy K, Rangan NS, Hosur RV, Kumar A. Disorder in CENP-A Cse4 tail-chaperone interaction facilitates binding with Ame1/Okp1 at the kinetochore. Structure 2024; 32:690-705.e6. [PMID: 38565139 DOI: 10.1016/j.str.2024.03.002] [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: 02/06/2023] [Revised: 11/16/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
The centromere is epigenetically marked by a histone H3 variant-CENP-A. The budding yeast CENP-A called Cse4, consists of an unusually long N-terminus that is known to be involved in kinetochore assembly. Its disordered chaperone, Scm3 is responsible for the centromeric deposition of Cse4 as well as in the maintenance of a segregation-competent kinetochore. In this study, we show that the Cse4 N-terminus is intrinsically disordered and interacts with Scm3 at multiple sites, and the complex does not gain any substantial structure. Additionally, the complex forms a synergistic association with an essential inner kinetochore component (Ctf19-Mcm21-Okp1-Ame1), and a model has been suggested to this effect. Thus, our study provides mechanistic insights into the Cse4 N-terminus-chaperone interaction and also illustrates how intrinsically disordered proteins mediate assembly of complex multiprotein networks, in general.
Collapse
Affiliation(s)
- Shivangi Shukla
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | | | - Parveen Sehrawat
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - Prakhar Agarwal
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - Rahul Shobhawat
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - Nikita Malik
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - Kalaiyarasi Duraisamy
- Centre for Advanced Protein Studies, Syngene International Limited, Bangalore, India
| | | | - Ramakrishna V Hosur
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - Ashutosh Kumar
- Department of Bioscience and Bioengineering, Indian Institute of Technology, Mumbai, India.
| |
Collapse
|
6
|
Lorton BM, Warren C, Ilyas H, Nandigrami P, Hegde S, Cahill S, Lehman SM, Shabanowitz J, Hunt DF, Fiser A, Cowburn D, Shechter D. Glutamylation of Npm2 and Nap1 acidic disordered regions increases DNA mimicry and histone chaperone efficiency. iScience 2024; 27:109458. [PMID: 38571760 PMCID: PMC10987829 DOI: 10.1016/j.isci.2024.109458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/08/2024] [Accepted: 03/07/2024] [Indexed: 04/05/2024] Open
Abstract
Histone chaperones-structurally diverse, non-catalytic proteins enriched with acidic intrinsically disordered regions (IDRs)-protect histones from spurious nucleic acid interactions and guide their deposition into and out of nucleosomes. Despite their conservation and ubiquity, the function of the chaperone acidic IDRs remains unclear. Here, we show that the Xenopus laevis Npm2 and Nap1 acidic IDRs are substrates for TTLL4 (Tubulin Tyrosine Ligase Like 4)-catalyzed post-translational glutamate-glutamylation. We demonstrate that to bind, stabilize, and deposit histones into nucleosomes, chaperone acidic IDRs function as DNA mimetics. Our biochemical, computational, and biophysical studies reveal that glutamylation of these chaperone polyelectrolyte acidic stretches functions to enhance DNA electrostatic mimicry, promoting the binding and stabilization of H2A/H2B heterodimers and facilitating nucleosome assembly. This discovery provides insights into both the previously unclear function of the acidic IDRs and the regulatory role of post-translational modifications in chromatin dynamics.
Collapse
Affiliation(s)
- Benjamin M. Lorton
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Christopher Warren
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Humaira Ilyas
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Prithviraj Nandigrami
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Systems & Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Subray Hegde
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Sean Cahill
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Stephanie M. Lehman
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - Donald F. Hunt
- Departments of Chemistry and Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Andras Fiser
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Systems & Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David Cowburn
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David Shechter
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| |
Collapse
|
7
|
King MR, Ruff KM, Lin AZ, Pant A, Farag M, Lalmansingh JM, Wu T, Fossat MJ, Ouyang W, Lew MD, Lundberg E, Vahey MD, Pappu RV. Macromolecular condensation organizes nucleolar sub-phases to set up a pH gradient. Cell 2024; 187:1889-1906.e24. [PMID: 38503281 DOI: 10.1016/j.cell.2024.02.029] [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: 07/18/2023] [Revised: 01/02/2024] [Accepted: 02/22/2024] [Indexed: 03/21/2024]
Abstract
Nucleoli are multicomponent condensates defined by coexisting sub-phases. We identified distinct intrinsically disordered regions (IDRs), including acidic (D/E) tracts and K-blocks interspersed by E-rich regions, as defining features of nucleolar proteins. We show that the localization preferences of nucleolar proteins are determined by their IDRs and the types of RNA or DNA binding domains they encompass. In vitro reconstitutions and studies in cells showed how condensation, which combines binding and complex coacervation of nucleolar components, contributes to nucleolar organization. D/E tracts of nucleolar proteins contribute to lowering the pH of co-condensates formed with nucleolar RNAs in vitro. In cells, this sets up a pH gradient between nucleoli and the nucleoplasm. By contrast, juxta-nucleolar bodies, which have different macromolecular compositions, featuring protein IDRs with very different charge profiles, have pH values that are equivalent to or higher than the nucleoplasm. Our findings show that distinct compositional specificities generate distinct physicochemical properties for condensates.
Collapse
Affiliation(s)
- Matthew R King
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Kiersten M Ruff
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrew Z Lin
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Avnika Pant
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Mina Farag
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jared M Lalmansingh
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Tingting Wu
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Department of Electrical and Systems Engineering, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Martin J Fossat
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Wei Ouyang
- Department of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA; Department of Pathology, School of Medicine, Stanford University, Stanford, CA, USA; Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Matthew D Lew
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Department of Electrical and Systems Engineering, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Emma Lundberg
- Department of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA; Department of Pathology, School of Medicine, Stanford University, Stanford, CA, USA; Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Michael D Vahey
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA.
| |
Collapse
|
8
|
Xie S, Yue C, Ye S, Li Z. Probing the hierarchical dynamics of DNA-sperm nuclear transition protein complexes through fuzzy interaction and mesoscale condensation. Phys Chem Chem Phys 2024; 26:10408-10418. [PMID: 38502252 DOI: 10.1039/d3cp05957j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Nuclear transition protein TNP1 is a crucial player mediating histone-protamine exchange in condensing spermatids. A unique combination of intrinsic disorder and multivalent properties turns TNP1 into an ideal agent for orchestrating the formation of versatile TNP-DNA assemblies. Despite its significance, the physicochemical property and the molecular mechanism followed by TNP1 for histone replacement and DNA condensation are still poorly understood. This study reports the first-time in vitro expression and purification of human TNP1 and investigates the hierarchical dynamics of TNP1-DNA interaction using a combination of computational simulations, biochemical assays, fluorescence imaging, and atomic force microscopy. We explored three crucial facets of TNP1-DNA interactions. Initially, we delve into the molecular binding process that entails fuzzy interactions between TNP1 and DNA at the atomistic scale. Subsequently, we analyze how TNP1 binding affects the electrostatic and mechanical characteristics of DNA and influences its morphology. Finally, we study the biomolecular condensation of TNP1-DNA when subjected to high concentrations. The findings of our study set the foundation for comprehending the potential involvement of TNP1 in histone replacement and DNA condensation in spermatogenesis.
Collapse
Affiliation(s)
- Shangqiang Xie
- School of Life Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
| | - Congran Yue
- School of Life Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
| | - Sheng Ye
- School of Life Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
- Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| | - Zhenlu Li
- School of Life Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
- Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| |
Collapse
|
9
|
Holehouse AS, Kragelund BB. The molecular basis for cellular function of intrinsically disordered protein regions. Nat Rev Mol Cell Biol 2024; 25:187-211. [PMID: 37957331 DOI: 10.1038/s41580-023-00673-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions exist in a collection of dynamic interconverting conformations that lack a stable 3D structure. These regions are structurally heterogeneous, ubiquitous and found across all kingdoms of life. Despite the absence of a defined 3D structure, disordered regions are essential for cellular processes ranging from transcriptional control and cell signalling to subcellular organization. Through their conformational malleability and adaptability, disordered regions extend the repertoire of macromolecular interactions and are readily tunable by their structural and chemical context, making them ideal responders to regulatory cues. Recent work has led to major advances in understanding the link between protein sequence and conformational behaviour in disordered regions, yet the link between sequence and molecular function is less well defined. Here we consider the biochemical and biophysical foundations that underlie how and why disordered regions can engage in productive cellular functions, provide examples of emerging concepts and discuss how protein disorder contributes to intracellular information processing and regulation of cellular function.
Collapse
Affiliation(s)
- Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, USA.
- Center for Biomolecular Condensates, Washington University in St Louis, St Louis, MO, USA.
| | - Birthe B Kragelund
- REPIN, Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
10
|
Kapoor U, Kim YC, Mittal J. Coarse-Grained Models to Study Protein-DNA Interactions and Liquid-Liquid Phase Separation. J Chem Theory Comput 2024; 20:1717-1731. [PMID: 37988476 PMCID: PMC10911113 DOI: 10.1021/acs.jctc.3c00525] [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: 05/19/2023] [Revised: 10/20/2023] [Accepted: 10/27/2023] [Indexed: 11/23/2023]
Abstract
Recent advances in coarse-grained (CG) computational models for DNA have enabled molecular-level insights into the behavior of DNA in complex multiscale systems. However, most existing CG DNA models are not compatible with CG protein models, limiting their applications for emerging topics such as protein-nucleic acid assemblies. Here, we present a new computationally efficient CG DNA model. We first use experimental data to establish the model's ability to predict various aspects of DNA behavior, including melting thermodynamics and relevant local structural properties such as the major and minor grooves. We then employ an all-atom hydropathy scale to define nonbonded interactions between protein and DNA sites, to make our DNA model compatible with an existing CG protein model (HPS-Urry), which is extensively used to study protein phase separation, and show that our new model reasonably reproduces the experimental binding affinity for a prototypical protein-DNA system. To further demonstrate the capabilities of this new model, we simulate a full nucleosome with and without histone tails, on a microsecond time scale, generating conformational ensembles and provide molecular insights into the role of histone tails in influencing the liquid-liquid phase separation (LLPS) of HP1α proteins. We find that histone tails interact favorably with DNA, influencing the conformational ensemble of the DNA and antagonizing the contacts between HP1α and DNA, thus affecting the ability of DNA to promote LLPS of HP1α. These findings shed light on the complex molecular framework that fine-tunes the phase transition properties of heterochromatin proteins and contributes to heterochromatin regulation and function. Overall, the CG DNA model presented here is suitable to facilitate micrometer-scale studies with sub-nm resolution in many biological and engineering applications and can be used to investigate protein-DNA complexes, such as nucleosomes, or LLPS of proteins with DNA, enabling a mechanistic understanding of how molecular information may be propagated at the genome level.
Collapse
Affiliation(s)
- Utkarsh Kapoor
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 78743, United States
| | - Young C. Kim
- Center
for Materials Physics and Technology, Naval
Research Laboratory, Washington, District of Columbia 20375, United States
| | - Jeetain Mittal
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 78743, United States
- Department
of Chemistry, Texas A&M University, College Station, Texas 78743, United States
- Interdisciplinary
Graduate Program in Genetics in Genomics, Texas A&M University, College
Station, Texas 78743, United States
| |
Collapse
|
11
|
Bjarnason S, McIvor JAP, Prestel A, Demény KS, Bullerjahn JT, Kragelund BB, Mercadante D, Heidarsson PO. DNA binding redistributes activation domain ensemble and accessibility in pioneer factor Sox2. Nat Commun 2024; 15:1445. [PMID: 38365983 PMCID: PMC10873366 DOI: 10.1038/s41467-024-45847-2] [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: 07/13/2023] [Accepted: 02/01/2024] [Indexed: 02/18/2024] Open
Abstract
More than 1600 human transcription factors orchestrate the transcriptional machinery to control gene expression and cell fate. Their function is conveyed through intrinsically disordered regions (IDRs) containing activation or repression domains but lacking quantitative structural ensemble models prevents their mechanistic decoding. Here we integrate single-molecule FRET and NMR spectroscopy with molecular simulations showing that DNA binding can lead to complex changes in the IDR ensemble and accessibility. The C-terminal IDR of pioneer factor Sox2 is highly disordered but its conformational dynamics are guided by weak and dynamic charge interactions with the folded DNA binding domain. Both DNA and nucleosome binding induce major rearrangements in the IDR ensemble without affecting DNA binding affinity. Remarkably, interdomain interactions are redistributed in complex with DNA leading to variable exposure of two activation domains critical for transcription. Charged intramolecular interactions allowing for dynamic redistributions may be common in transcription factors and necessary for sensitive tuning of structural ensembles.
Collapse
Affiliation(s)
- Sveinn Bjarnason
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland
| | - Jordan A P McIvor
- School of Chemical Science, University of Auckland, Auckland, New Zealand
| | - Andreas Prestel
- Department of Biology, REPIN and Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen, Denmark
| | - Kinga S Demény
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland
| | - Jakob T Bullerjahn
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Birthe B Kragelund
- Department of Biology, REPIN and Structural Biology and NMR Laboratory, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen, Denmark
| | - Davide Mercadante
- School of Chemical Science, University of Auckland, Auckland, New Zealand.
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Sturlugata 7, 102, Reykjavík, Iceland.
| |
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- Hagen Hofmann
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Herzl St. 234, 76100 Rehovot, Israel.
| |
Collapse
|
13
|
Chowdhury A, Borgia A, Ghosh S, Sottini A, Mitra S, Eapen RS, Borgia MB, Yang T, Galvanetto N, Ivanović MT, Łukijańczuk P, Zhu R, Nettels D, Kundagrami A, Schuler B. Driving forces of the complex formation between highly charged disordered proteins. Proc Natl Acad Sci U S A 2023; 120:e2304036120. [PMID: 37796987 PMCID: PMC10576128 DOI: 10.1073/pnas.2304036120] [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: 03/14/2023] [Accepted: 08/22/2023] [Indexed: 10/07/2023] Open
Abstract
Highly disordered complexes between oppositely charged intrinsically disordered proteins present a new paradigm of biomolecular interactions. Here, we investigate the driving forces of such interactions for the example of the highly positively charged linker histone H1 and its highly negatively charged chaperone, prothymosin α (ProTα). Temperature-dependent single-molecule Förster resonance energy transfer (FRET) experiments and isothermal titration calorimetry reveal ProTα-H1 binding to be enthalpically unfavorable, and salt-dependent affinity measurements suggest counterion release entropy to be an important thermodynamic driving force. Using single-molecule FRET, we also identify ternary complexes between ProTα and H1 in addition to the heterodimer at equilibrium and show how they contribute to the thermodynamics observed in ensemble experiments. Finally, we explain the observed thermodynamics quantitatively with a mean-field polyelectrolyte theory that treats counterion release explicitly. ProTα-H1 complex formation resembles the interactions between synthetic polyelectrolytes, and the underlying principles are likely to be of broad relevance for interactions between charged biomolecules in general.
Collapse
Affiliation(s)
- Aritra Chowdhury
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Alessandro Borgia
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Souradeep Ghosh
- Department of Physical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur741246, India
| | - Andrea Sottini
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Soumik Mitra
- Department of Physical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur741246, India
| | - Rohan S. Eapen
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | | | - Tianjin Yang
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Nicola Galvanetto
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
- Department of Physics, University of Zurich, Zurich8057, Switzerland
| | - Miloš T. Ivanović
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Paweł Łukijańczuk
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Ruijing Zhu
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
| | - Arindam Kundagrami
- Department of Physical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur741246, India
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Zurich8057, Switzerland
- Department of Physics, University of Zurich, Zurich8057, Switzerland
| |
Collapse
|
14
|
Das SK, Kumar A, Hao F, Cutter DiPiazza AR, Fang H, Lee TH, Hayes JJ. Histone H3 Tail Modifications Alter Structure and Dynamics of the H1 C-Terminal Domain Within Nucleosomes. J Mol Biol 2023; 435:168242. [PMID: 37619707 PMCID: PMC10530611 DOI: 10.1016/j.jmb.2023.168242] [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: 06/27/2023] [Revised: 08/10/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023]
Abstract
The highly positively charged and intrinsically disordered H1 C-terminal domain (CTD) undergoes extensive condensation upon binding to nucleosomes, and stabilizes nucleosomes and higher-order chromatin structures but its interactions in chromatin are not well defined. Using single-molecule FRET we found that about half of the H1 CTDs in H1-nucleosome complexes exhibit well-defined FRET values indicative of distinct, static conformations, while the remainder of the population exhibits exchange between multiple defined FRET structures. Moreover, crosslinking studies indicate that the first 30 residues of the H1 CTD participate in relatively localized contacts with the first ∼25 bp of linker DNA, and that two separate regions in the CTD contribute to H1-dependent organization of linker DNA. Finally, we show that acetylation mimetics within the histone H3 tail markedly reduce the overall extent of H1 CTD condensation and significantly increase the fraction of H1 CTDs undergoing dynamic exchange between FRET states. Our results indicate the nucleosome-bound H1 CTD adopts loosely defined structures that exhibit significantly enhanced dynamics and decondensation upon epigenetic acetylation within the H3 tail.
Collapse
Affiliation(s)
- Subhra Kanti Das
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Ashok Kumar
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Fanfan Hao
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Amber R Cutter DiPiazza
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - He Fang
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States
| | - Tae-Hee Lee
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Jeffrey J Hayes
- Department of Biochemistry and Biophysics, Rochester University Medical Center, Rochester, NY 14625, United States.
| |
Collapse
|
15
|
Lorton BM, Warren C, Ilyas H, Nandigrami P, Hegde S, Cahill S, Lehman SM, Shabanowitz J, Hunt DF, Fiser A, Cowburn D, Shechter D. Glutamylation of Npm2 and Nap1 acidic disordered regions increases DNA charge mimicry to enhance chaperone efficiency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.18.558337. [PMID: 37790377 PMCID: PMC10542154 DOI: 10.1101/2023.09.18.558337] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Histone chaperones-structurally diverse, non-catalytic proteins enriched with acidic intrinsically disordered regions (IDRs)-protect histones from spurious nucleic acid interactions and guide their deposition into and out of nucleosomes. Despite their conservation and ubiquity, the function of the chaperone acidic IDRs remains unclear. Here, we show that the Xenopus laevis Npm2 and Nap1 acidic IDRs are substrates for TTLL4 (Tubulin Tyrosine Ligase Like 4)-catalyzed post-translational glutamate-glutamylation. We demonstrate that, to bind, stabilize, and deposit histones into nucleosomes, chaperone acidic IDRs function as DNA mimetics. Our biochemical, computational, and biophysical studies reveal that glutamylation of these chaperone polyelectrolyte acidic stretches functions to enhance DNA electrostatic mimicry, promoting the binding and stabilization of H2A/H2B heterodimers and facilitating nucleosome assembly. This discovery provides insights into both the previously unclear function of the acidic IDRs and the regulatory role of post-translational modifications in chromatin dynamics.
Collapse
Affiliation(s)
- Benjamin M. Lorton
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Christopher Warren
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
- Current address: Merck & Co., Inc., 2025 E Scott Ave., Rahway, NJ 07065
| | - Humaira Ilyas
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Prithviraj Nandigrami
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
- Department of Systems & Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Subray Hegde
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Sean Cahill
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Stephanie M Lehman
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
- GSK, Collegeville, Pennsylvania 19426
| | | | - Donald F. Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
- Departments of Chemistry and Pathology, University of Virginia, Charlottesville, VA 22904
| | - Andras Fiser
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
- Department of Systems & Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - David Cowburn
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - David Shechter
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| |
Collapse
|
16
|
Abstract
Multivalent proteins and nucleic acids, collectively referred to as multivalent associative biomacromolecules, provide the driving forces for the formation and compositional regulation of biomolecular condensates. Here, we review the key concepts of phase transitions of aqueous solutions of associative biomacromolecules, specifically proteins that include folded domains and intrinsically disordered regions. The phase transitions of these systems come under the rubric of coupled associative and segregative transitions. The concepts underlying these processes are presented, and their relevance to biomolecular condensates is discussed.
Collapse
Affiliation(s)
- Rohit V Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Samuel R Cohen
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Furqan Dar
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| |
Collapse
|
17
|
Galvanetto N, Ivanović MT, Chowdhury A, Sottini A, Nüesch MF, Nettels D, Best RB, Schuler B. Extreme dynamics in a biomolecular condensate. Nature 2023:10.1038/s41586-023-06329-5. [PMID: 37468629 DOI: 10.1038/s41586-023-06329-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 06/14/2023] [Indexed: 07/21/2023]
Abstract
Proteins and nucleic acids can phase-separate in the cell to form concentrated biomolecular condensates1-4. The functions of condensates span many length scales: they modulate interactions and chemical reactions at the molecular scale5, organize biochemical processes at the mesoscale6 and compartmentalize cells4. Understanding the underlying mechanisms of these processes will require detailed knowledge of the rich dynamics across these scales7. The mesoscopic dynamics of biomolecular condensates have been extensively characterized8, but their behaviour at the molecular scale has remained more elusive. Here, as an example of biomolecular phase separation, we study complex coacervates of two highly and oppositely charged disordered human proteins9. Their dense phase is 1,000 times more concentrated than the dilute phase, and the resulting percolated interaction network10 leads to a bulk viscosity 300 times greater than that of water. However, single-molecule spectroscopy optimized for measurements within individual droplets reveals that at the molecular scale, the disordered proteins remain exceedingly dynamic, with their chain configurations interconverting on submicrosecond timescales. Massive all-atom molecular dynamics simulations reproduce the experimental observations and explain this apparent discrepancy: the underlying interactions between individual charged side chains are short-lived and exchange on a pico- to nanosecond timescale. Our results indicate that, despite the high macroscopic viscosity of phase-separated systems, local biomolecular rearrangements required for efficient reactions at the molecular scale can remain rapid.
Collapse
Affiliation(s)
- Nicola Galvanetto
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
- Department of Physics, University of Zurich, Zurich, Switzerland.
| | - Miloš T Ivanović
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
| | - Aritra Chowdhury
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Andrea Sottini
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Mark F Nüesch
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
- Department of Physics, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
18
|
Kapoor U, Kim YC, Mittal J. A coarse-grained DNA model to study protein-DNA interactions and liquid-liquid phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541513. [PMID: 37292850 PMCID: PMC10245785 DOI: 10.1101/2023.05.19.541513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recent advances in coarse-grained (CG) computational models for DNA have enabled molecular-level insights into the behavior of DNA in complex multiscale systems. However, most existing CG DNA models are not compatible with CG protein models, limiting their applications for emerging topics such as protein-nucleic acid assemblies. Here, we present a new computationally efficient CG DNA model. We first use experimental data to establish the model's ability to predict various aspects of DNA behavior, including melting thermodynamics and relevant local structural properties such as the major and minor grooves. We then employ an all-atom hydropathy scale to define non-bonded interactions between protein and DNA sites, to make our DNA model compatible with an existing CG protein model (HPS-Urry), that is extensively used to study protein phase separation, and show that our new model reasonably reproduces the experimental binding affinity for a prototypical protein-DNA system. To further demonstrate the capabilities of this new model, we simulate a full nucleosome with and without histone tails, on a microsecond timescale, generating conformational ensembles and provide molecular insights into the role of histone tails in influencing the liquid-liquid phase separation (LLPS) of HP1α proteins. We find that histone tails interact favorably with DNA, influencing the conformational ensemble of the DNA and antagonizing the contacts between HP1α and DNA, thus affecting the ability of DNA to promote LLPS of HP1α. These findings shed light on the complex molecular framework that fine-tunes the phase transition properties of heterochromatin proteins and contributes to heterochromatin regulation and function. Overall, the CG DNA model presented here is suitable to facilitate micron-scale studies with sub-nm resolution in many biological and engineering applications and can be used to investigate protein-DNA complexes, such as nucleosomes, or LLPS of proteins with DNA, enabling a mechanistic understanding of how molecular information may be propagated at the genome level.
Collapse
Affiliation(s)
- Utkarsh Kapoor
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 78743, United States
| | - Young C. Kim
- Center for Materials Physics and Technology, Naval Research Laboratory, Washington, District of Columbia
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 78743, United States
- Department of Chemistry, Texas A&M University, College Station, Texas 78743, United States
- Interdisciplinary Graduate Program in Genetics in Genomics, Texas A&M University, College Station, Texas 78743, United States
| |
Collapse
|
19
|
Das SK, Kumar A, Hao F, DiPiazza ARC, Lee TH, Hayes JJ. Histone H3 tail modifications regulate structure and dynamics of the H1 C-terminal domain within nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540398. [PMID: 37214834 PMCID: PMC10197648 DOI: 10.1101/2023.05.11.540398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Despite their importance, how linker histone H1s interact in chromatin and especially how the highly positively charged and intrinsically disordered H1 C-terminal domain (CTD) binds and stabilizes nucleosomes and higher-order chromatin structures remains unclear. Using single-molecule FRET we found that about half of the H1 CTDs in H1-nucleosome complexes exhibit well-defined FRET values indicative of distinct, static conformations, while the remainder of the population exhibits dynamically changing values, similar to that observed for H1 in the absence of nucleosomes. We also find that the first 30 residues of the CTD participate in relatively localized interactions with the first ∼20 bp of linker DNA, and that two separate regions in the CTD contribute to H1-dependent organization of linker DNA, consistent with some non-random CTD-linker DNA interactions. Finally, our data show that acetylation mimetics within the histone H3 tail induce decondensation and enhanced dynamics of the nucleosome-bound H1 CTD. (148 words).
Collapse
|
20
|
Tan C, Niitsu A, Sugita Y. Highly Charged Proteins and Their Repulsive Interactions Antagonize Biomolecular Condensation. JACS AU 2023; 3:834-848. [PMID: 37006777 PMCID: PMC10052238 DOI: 10.1021/jacsau.2c00646] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 06/19/2023]
Abstract
Biomolecular condensation is involved in various cellular processes; therefore, regulation of condensation is crucial to prevent deleterious protein aggregation and maintain a stable cellular environment. Recently, a class of highly charged proteins, known as heat-resistant obscure (Hero) proteins, was shown to protect other client proteins from pathological aggregation. However, the molecular mechanisms by which Hero proteins protect other proteins from aggregation remain unknown. In this study, we performed multiscale molecular dynamics (MD) simulations of Hero11, a Hero protein, and the C-terminal low-complexity domain (LCD) of the transactive response DNA-binding protein 43 (TDP-43), a client protein of Hero11, under various conditions to examine their interactions with each other. We found that Hero11 permeates into the condensate formed by the LCD of TDP-43 (TDP-43-LCD) and induces changes in conformation, intermolecular interactions, and dynamics of TDP-43-LCD. We also examined possible Hero11 structures in atomistic and coarse-grained MD simulations and found that Hero11 with a higher fraction of disordered region tends to assemble on the surface of the condensates. Based on the simulation results, we have proposed three possible mechanisms for Hero11's regulatory function: (i) In the dense phase, TDP-43-LCD reduces contact with each other and shows faster diffusion and decondensation due to the repulsive Hero11-Hero11 interactions. (ii) In the dilute phase, the saturation concentration of TDP-43-LCD is increased, and its conformation is relatively more extended and variant, induced by the attractive Hero11-TDP-43-LCD interactions. (iii) Hero11 on the surface of small TDP-43-LCD condensates can contribute to avoiding their fusion due to repulsive interactions. The proposed mechanisms provide new insights into the regulation of biomolecular condensation in cells under various conditions.
Collapse
Affiliation(s)
- Cheng Tan
- Computational
Biophysics Research Team, RIKEN Center for
Computational Science, Kobe, Hyogo 650-0047, Japan
| | - Ai Niitsu
- Theoretical
Molecular Science Laboratory, RIKEN Cluster
for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Yuji Sugita
- Computational
Biophysics Research Team, RIKEN Center for
Computational Science, Kobe, Hyogo 650-0047, Japan
- Theoretical
Molecular Science Laboratory, RIKEN Cluster
for Pioneering Research, Wako, Saitama 351-0198, Japan
- Laboratory
for Biomolecular Function Simulation, RIKEN
Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| |
Collapse
|
21
|
Wang Y, Chang H, Jiang S, Chen J, Wang J, Liang H, Li G, Tang X. An efficient co-solvent tailoring interfacial polymerization for nanofiltration: Enhanced selectivity and mechanism. J Memb Sci 2023. [DOI: 10.1016/j.memsci.2023.121615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
|
22
|
The biophysics of disordered proteins from the point of view of single-molecule fluorescence spectroscopy. Essays Biochem 2022; 66:875-890. [PMID: 36416865 PMCID: PMC9760427 DOI: 10.1042/ebc20220065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/24/2022]
Abstract
Intrinsically disordered proteins (IDPs) and regions (IDRs) have emerged as key players across many biological functions and diseases. Differently from structured proteins, disordered proteins lack stable structure and are particularly sensitive to changes in the surrounding environment. Investigation of disordered ensembles requires new approaches and concepts for quantifying conformations, dynamics, and interactions. Here, we provide a short description of the fundamental biophysical properties of disordered proteins as understood through the lens of single-molecule fluorescence observations. Single-molecule Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) provides an extensive and versatile toolbox for quantifying the characteristics of conformational distributions and the dynamics of disordered proteins across many different solution conditions, both in vitro and in living cells.
Collapse
|
23
|
Feng H, Zhou BR, Schwieters CD, Bai Y. Structural Mechanism of TAF-Iβ Chaperone Function on Linker Histone H1.10. J Mol Biol 2022; 434:167755. [PMID: 35870650 PMCID: PMC9489631 DOI: 10.1016/j.jmb.2022.167755] [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: 05/10/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022]
Abstract
Linker histone H1, facilitated by its chaperones, plays an essential role in regulating gene expression by maintaining chromatin's higher-order structure and epigenetic state. However, we know little about the structural mechanism of how the chaperones recognize linker histones and conduct their function. Here, we used biophysical and biochemical methods to investigate the recognition of human linker histone isoform H1.10 by the TAF-Iβ chaperone. Both H1.10 and TAF-Iβ proteins consist of folded cores and disordered tails. We found that H1.10 formed a complex with TAF-Iβ in a 2:2 stoichiometry. Using distance restraints obtained from methyl-TROSY NMR and spin labels, we built a structural model for the core region of the complex. In the model, the TAF-Iβ core interacts with the globular domain of H1.10 mainly through electrostatic interactions. We confirmed the interactions by measuring the effects of mutations on the binding affinity. A comparison of our structural model with the chromatosome structure shows that TAF-Iβ blocks the DNA binding sites of H1.10. Our study provides insights into the structural mechanism whereby TAF-Iβ functions as a chaperone by preventing H1.10 from interacting with DNA directly.
Collapse
Affiliation(s)
- Haniqao Feng
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bing-Rui Zhou
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Charles D Schwieters
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yawen Bai
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
24
|
Affinity of disordered protein complexes is modulated by entropy-energy reinforcement. Proc Natl Acad Sci U S A 2022; 119:e2120456119. [PMID: 35727975 PMCID: PMC9245678 DOI: 10.1073/pnas.2120456119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intrinsically disordered proteins (IDPs), which are very common and essential to many biological activities, sometimes function via interaction with another IDP and form a fuzzy complex, which can be highly stable. It is unclear what the biophysical forces are that govern their thermodynamics and specificity, which are essential for de novo fuzzy complex design. Here, we explored the fuzzy complex formed between ProTα and H1, which are oppositely charged IDPs, by swapping the charges between them, generating variants that have either greater polyampholytic or polyelectrolytic nature as well as different charge patterns. Charge swapping and shuffling dramatically change the affinity of the fuzzy complex, which is contributed to by both enthalpy and entropy, where the latter is dominated by counterion release. The association between two intrinsically disordered proteins (IDPs) may produce a fuzzy complex characterized by a high binding affinity, similar to that found in the ultrastable complexes formed between two well-structured proteins. Here, using coarse-grained simulations, we quantified the biophysical forces driving the formation of such fuzzy complexes. We found that the high-affinity complex formed between the highly and oppositely charged H1 and ProTα proteins is sensitive to electrostatic interactions. We investigated 52 variants of the complex by swapping charges between the two oppositely charged proteins to produce sequences whose negatively or positively charged residue content was more homogeneous or heterogenous (i.e., polyelectrolytic or polyampholytic, having higher or lower absolute net charges, respectively) than the wild type. We also changed the distributions of oppositely charged residues within each participating sequence to produce variants in which the charges were segregated or well mixed. Both types of changes significantly affect binding affinity in fuzzy complexes, which is governed by both enthalpy and entropy. The formation of H1–ProTa is supported by an increase in configurational entropy and by entropy due to counterion release. The latter can be twice as large as the former, illustrating the dominance of counterion entropy in modulating the binding thermodynamics. Complexes formed between proteins with greater absolute net charges are more stable, both enthalpically and entropically, indicating that enthalpy and entropy have a mutually reinforcing effect. The sensitivity of the thermodynamics of the complex to net charge and the charge pattern within each of the binding constituents may provide a means to achieve binding specificity between IDPs.
Collapse
|
25
|
Mittag T, Pappu RV. A conceptual framework for understanding phase separation and addressing open questions and challenges. Mol Cell 2022; 82:2201-2214. [PMID: 35675815 PMCID: PMC9233049 DOI: 10.1016/j.molcel.2022.05.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 05/04/2022] [Accepted: 05/13/2022] [Indexed: 12/11/2022]
Abstract
Macromolecular phase separation is being recognized for its potential importance and relevance as a driver of spatial organization within cells. Here, we describe a framework based on synergies between networking (percolation or gelation) and density (phase separation) transitions. Accordingly, the phase transitions in question are referred to as phase separation coupled to percolation (PSCP). The condensates that result from PSCP are viscoelastic network fluids. Such systems have sequence-, composition-, and topology-specific internal network structures that give rise to time-dependent interplays between viscous and elastic properties. Unlike pure phase separation, the process of PSCP gives rise to sequence-, chemistry-, and structure-specific distributions of clusters that can form at concentrations that lie well below the threshold concentration for phase separation. PSCP, influenced by specific versus solubility-determining interactions, also provides a bridge between different observations and helps answer questions and address challenges that have arisen regarding the role of macromolecular phase separation in biology.
Collapse
Affiliation(s)
- Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA.
| |
Collapse
|
26
|
Bigman LS, Iwahara J, Levy Y. Negatively Charged Disordered Regions are Prevalent and Functionally Important Across Proteomes. J Mol Biol 2022; 434:167660. [PMID: 35659505 DOI: 10.1016/j.jmb.2022.167660] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 01/12/2023]
Abstract
Intrinsically disordered regions (IDRs) of proteins are often characterized by a high fraction of charged residues, but differ in their overall net charge and in the organization of the charged residues. The function-encoding information stored via IDR charge composition and organization remains elusive. Here, we aim to decipher the sequence-function relationship in IDRs by presenting a comprehensive bioinformatic analysis of the charge properties of IDRs in the human, mouse, and yeast proteomes. About 50% of the proteins comprise at least a single IDR, which is either positively or negatively charged. Highly negatively charged IDRs are longer and possess greater net charge per residue compared with highly positively charged IDRs. A striking difference between positively and negatively charged IDRs is the characteristics of the repeated units, specifically, of consecutive Lys or Arg residues (K/R repeats) and Asp or Glu (D/E repeats) residues. D/E repeats are found to be about five times longer than K/R repeats, with the longest found containing 49 residues. Long stretches of consecutive D and E are found to be more prevalent in nucleic acid-related proteins. They are less common in prokaryotes, and in eukaryotes their abundance increases with genome size. The functional role of D/E repeats and the profound differences between them and K/R repeats are discussed.
Collapse
Affiliation(s)
- Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel. https://twitter.com/LaviBigman
| | - Junji Iwahara
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
27
|
Zeng X, Ruff KM, Pappu RV. Competing interactions give rise to two-state behavior and switch-like transitions in charge-rich intrinsically disordered proteins. Proc Natl Acad Sci U S A 2022; 119:e2200559119. [PMID: 35512095 PMCID: PMC9171777 DOI: 10.1073/pnas.2200559119] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/12/2022] [Indexed: 11/18/2022] Open
Abstract
The most commonly occurring intrinsically disordered proteins (IDPs) are polyampholytes, which are defined by the duality of low net charge per residue and high fractions of charged residues. Recent experiments have uncovered nuances regarding sequence–ensemble relationships of model polyampholytic IDPs. These include differences in conformational preferences for sequences with lysine vs. arginine and the suggestion that well-mixed sequences form a range of conformations, including globules, conformations with ensemble averages that are reminiscent of ideal chains, or self-avoiding walks. Here, we explain these observations by analyzing results from atomistic simulations. We find that polyampholytic IDPs generally sample two distinct stable states, namely, globules and self-avoiding walks. Globules are favored by electrostatic attractions between oppositely charged residues, whereas self-avoiding walks are favored by favorable free energies of hydration of charged residues. We find sequence-specific temperatures of bistability at which globules and self-avoiding walks can coexist. At these temperatures, ensemble averages over coexisting states give rise to statistics that resemble ideal chains without there being an actual counterbalancing of intrachain and chain-solvent interactions. At equivalent temperatures, arginine-rich sequences tilt the preference toward globular conformations whereas lysine-rich sequences tilt the preference toward self-avoiding walks. We also identify differences between aspartate- and glutamate-containing sequences, whereby the shorter aspartate side chain engenders preferences for metastable, necklace-like conformations. Finally, although segregation of oppositely charged residues within the linear sequence maintains the overall two-state behavior, compact states are highly favored by such systems.
Collapse
Affiliation(s)
- Xiangze Zeng
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
| | - Kiersten M. Ruff
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
| |
Collapse
|
28
|
Shi X, Zhai Z, Chen Y, Li J, Nordenskiöld L. Recent Advances in Investigating Functional Dynamics of Chromatin. Front Genet 2022; 13:870640. [PMID: 35450211 PMCID: PMC9017861 DOI: 10.3389/fgene.2022.870640] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/11/2022] [Indexed: 11/26/2022] Open
Abstract
Dynamics spanning the picosecond-minute time domain and the atomic-subcellular spatial window have been observed for chromatin in vitro and in vivo. The condensed organization of chromatin in eukaryotic cells prevents regulatory factors from accessing genomic DNA, which requires dynamic stabilization and destabilization of structure to initiate downstream DNA activities. Those processes are achieved through altering conformational and dynamic properties of nucleosomes and nucleosome–protein complexes, of which delineating the atomistic pictures is essential to understand the mechanisms of chromatin regulation. In this review, we summarize recent progress in determining chromatin dynamics and their modulations by a number of factors including post-translational modifications (PTMs), incorporation of histone variants, and binding of effector proteins. We focus on experimental observations obtained using high-resolution techniques, primarily including nuclear magnetic resonance (NMR) spectroscopy, Förster (or fluorescence) resonance energy transfer (FRET) microscopy, and molecular dynamics (MD) simulations, and discuss the elucidated dynamics in the context of functional response and relevance.
Collapse
Affiliation(s)
- Xiangyan Shi
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Ziwei Zhai
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Yinglu Chen
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Jindi Li
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, China
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
29
|
Lebold KM, Best RB. Tuning Formation of Protein-DNA Coacervates by Sequence and Environment. J Phys Chem B 2022; 126:2407-2419. [PMID: 35317553 DOI: 10.1021/acs.jpcb.2c00424] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The high concentration of nucleic acids and positively charged proteins in the cell nucleus provides many possibilities for complex coacervation. We consider a prototypical mixture of nucleic acids together with the polycationic C-terminus of histone H1 (CH1). Using a minimal coarse-grained model that captures the shape, flexibility, and charge distributions of the molecules, we find that coacervates are readily formed at physiological ionic strengths, in agreement with experiment, with a progressive increase in local ordering at low ionic strength. Variation of the positions of charged residues in the protein tunes phase separation: for well-mixed or only moderately blocky distributions of charge, there is a modest increase of local ordering with increasing blockiness that is also associated with an increased propensity to phase separate. This ordering is also associated with a slowdown of rotational and translational diffusion in the dense phase. However, for more extreme blockiness (and consequently higher local charge density), we see a qualitative change in the condensed phase to become a segregated structure with a dramatically increased ordering of the DNA. Naturally occurring proteins with these sequence properties, such as protamines in sperm cells, are found to be associated with very dense packing of nucleic acids.
Collapse
Affiliation(s)
- Kathryn M Lebold
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Robert B Best
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| |
Collapse
|
30
|
Martinsen JH, Saar D, Fernandes CB, Schuler B, Bugge K, Kragelund BB. Structure, Dynamics and Stability of the Globular Domain of Human Linker Histone H1.0 and the Role of Positive Charges. Protein Sci 2022; 31:918-932. [PMID: 35066947 PMCID: PMC8927875 DOI: 10.1002/pro.4281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/14/2022] [Accepted: 01/20/2022] [Indexed: 11/25/2022]
Abstract
Linker histone H1 (H1) is an abundant chromatin‐binding protein that acts as an epigenetic regulator binding to nucleosomes and altering chromatin structures and dynamics. Nonetheless, the mechanistic details of its function remain poorly understood. Recent work suggest that the number and position of charged side chains on the globular domain (GD) of H1 influence chromatin structure and hence gene repression. Here, we solved the solution structure of the unbound GD of human H1.0, revealing that the structure is almost completely unperturbed by complex formation, except for a loop connecting two antiparallel β‐strands. We further quantified the role of the many positive charges of the GD for its structure and conformational stability through the analysis of 11 charge variants. We find that modulating the number of charges has little effect on the structure, but the stability is affected, resulting in a difference in melting temperature of 26 K between GD of net charge +5 versus +13. This result suggests that the large number of positive charges on H1‐GDs have evolved for function rather than structure and high stability. The stabilization of the GD upon binding to DNA can thus be expected to have a pronounced electrostatic component, a contribution that is amenable to modulation by posttranslational modifications, especially acetylation and phosphorylation. PDB Code(s): 6hq1;
Collapse
Affiliation(s)
- Jacob H Martinsen
- REPIN and the Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Ole Maaloes Vej 5, DK-.2200, Copenhagen N, Denmark
| | - Daniel Saar
- REPIN and the Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Ole Maaloes Vej 5, DK-.2200, Copenhagen N, Denmark
| | - Catarina B Fernandes
- REPIN and the Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Ole Maaloes Vej 5, DK-.2200, Copenhagen N, Denmark
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.,Department of Physics, Winterthurerstrasse 190, 8057 University of Zurich, Zurich, Switzerland
| | - Katrine Bugge
- REPIN and the Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Ole Maaloes Vej 5, DK-.2200, Copenhagen N, Denmark
| | - Birthe B Kragelund
- REPIN and the Structural Biology and NMR Laboratory, The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Ole Maaloes Vej 5, DK-.2200, Copenhagen N, Denmark
| |
Collapse
|