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MacAinsh M, Dey S, Zhou HX. Direct and indirect salt effects on homotypic phase separation. eLife 2024; 13:RP100282. [PMID: 39531035 PMCID: PMC11556789 DOI: 10.7554/elife.100282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2024] Open
Abstract
The low-complexity domain of hnRNPA1 (A1-LCD) phase separates in a salt-dependent manner. Unlike many intrinsically disordered proteins (IDPs) whose phase separation is suppressed by increasing salt concentrations, the phase separation of A1-LCD is promoted by >100 mM NaCl. To investigate the atypical salt effect on A1-LCD phase separation, we carried out all-atom molecular dynamics simulations of systems comprising multiple A1-LCD chains at NaCl concentrations from 50 to 1000 mM NaCl. The ions occupy first shell as well as more distant sites around the IDP chains, with Arg sidechains and backbone carbonyls the favored partners of Cl- and Na+, respectively. They play two direct roles in driving A1-LCD condensation. The first is to neutralize the high net charge of the protein (+9) by an excess of bound Cl- over Na+; the second is to bridge between A1-LCD chains, thereby fortifying the intermolecular interaction networks in the dense phase. At high concentrations, NaCl also indirectly strengthens π-π, cation-π, and amino-π interactions, by drawing water away from the interaction partners. Therefore, at low salt, A1-LCD is prevented from phase separation by net charge repulsion; at intermediate concentrations, NaCl neutralizes enough of the net charge while also bridging IDP chains to drive phase separation. This drive becomes even stronger at high salt due to strengthened π-type interactions. Based on this understanding, four classes of salt dependence of IDP phase separation can be predicted from amino-acid composition.
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Affiliation(s)
- Matt MacAinsh
- Department of Chemistry, University of Illinois ChicagoChicagoUnited States
| | - Souvik Dey
- Department of Chemistry, University of Illinois ChicagoChicagoUnited States
| | - Huan-Xiang Zhou
- Department of Chemistry, University of Illinois ChicagoChicagoUnited States
- Department of Physics, University of Illinois ChicagoChicagoUnited States
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Swain BC, Sarkis P, Ung V, Rousseau S, Fernandez L, Meltonyan A, Aho VE, Mercadante D, Mackereth CD, Aznauryan M. Disordered regions of human eIF4B orchestrate a dynamic self-association landscape. Nat Commun 2024; 15:8766. [PMID: 39384813 PMCID: PMC11464913 DOI: 10.1038/s41467-024-53136-1] [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: 06/21/2024] [Accepted: 10/03/2024] [Indexed: 10/11/2024] Open
Abstract
Eukaryotic translation initiation factor eIF4B is required for efficient cap-dependent translation, it is overexpressed in cancer cells, and may influence stress granule formation. Due to the high degree of intrinsic disorder, eIF4B is rarely observed in cryo-EM structures of translation complexes and only ever by its single structured RNA recognition motif domain, leaving the molecular details of its large intrinsically disordered region (IDR) unknown. By integrating experiments and simulations we demonstrate that eIF4B IDR orchestrates and fine-tunes an intricate transition from monomers to a condensed phase, in which large-size dynamic oligomers form before mesoscopic phase separation. Single-molecule spectroscopy combined with molecular simulations enabled us to characterize the conformational ensembles and underlying intra- and intermolecular dynamics across the oligomerization transition. The observed sensitivity to ionic strength and molecular crowding in the self-association landscape suggests potential regulation of eIF4B nanoscopic and mesoscopic behaviors such as driven by protein modifications, binding partners or changes to the cellular environment.
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Affiliation(s)
- Bikash Chandra Swain
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
| | - Pascale Sarkis
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
| | - Vanessa Ung
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Sabrina Rousseau
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
| | - Laurent Fernandez
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
| | - Ani Meltonyan
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
| | - V Esperance Aho
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France
- Institut de Biologie Structurale (IBS), UMR 5075, F-38044, Grenoble, France
| | - Davide Mercadante
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Cameron D Mackereth
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, F-33000, Bordeaux, France.
| | - Mikayel Aznauryan
- University of Bordeaux, Inserm, CNRS, ARNA Laboratory, U1212, UMR 5320, Institut Européen de Chimie et Biologie, F-33600, Pessac, France.
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Meng QW, Li J, Lai Z, Xian W, Wang S, Chen F, Dai Z, Zhang L, Yin H, Ma S, Sun Q. Optimizing selectivity via membrane molecular packing manipulation for simultaneous cation and anion screening. SCIENCE ADVANCES 2024; 10:eado8658. [PMID: 39321297 PMCID: PMC11423885 DOI: 10.1126/sciadv.ado8658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 08/21/2024] [Indexed: 09/27/2024]
Abstract
Advancing membranes with enhanced solute-solute selectivity is essential for expanding membrane technology applications, yet it presents a notable challenge. Drawing inspiration from the unparalleled selectivity of biological systems, which benefit from the sophisticated spatial organization of functionalities, we posit that manipulating the arrangement of the membrane's building blocks, an aspect previously given limited attention, can address this challenge. We demonstrate that optimizing the face-to-face orientation of building blocks during the assembly of covalent-organic-framework (COF) membranes improves ion-π interactions with multivalent ions. This optimization leads to extraordinary selectivity in differentiating between monovalent cations and anions from their multivalent counterparts, achieving selectivity factors of 214 for K+/Al3+ and 451 for NO3-/PO43-. Leveraging this attribute, the COF membrane facilitates the direct extraction of NaCl from seawater with a purity of 99.57%. These findings offer an alternative approach for designing highly selective membrane materials, offering promising prospects for advancing membrane-based technologies.
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Affiliation(s)
- Qing-Wei Meng
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jianguo Li
- Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Zhuozhi Lai
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Weipeng Xian
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Sai Wang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Fang Chen
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhifeng Dai
- Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Li Zhang
- Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Hong Yin
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Shengqian Ma
- Department of Chemistry, University of North Texas, 1508 W Mulberry St., Denton, TX 76201, USA
| | - Qi Sun
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
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Calinsky R, Levy Y. A pH-Dependent Coarse-Grained Model for Disordered Proteins: Histidine Interactions Modulate Conformational Ensembles. J Phys Chem Lett 2024; 15:9419-9430. [PMID: 39248414 PMCID: PMC11417990 DOI: 10.1021/acs.jpclett.4c02314] [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: 08/06/2024] [Revised: 08/30/2024] [Accepted: 09/04/2024] [Indexed: 09/10/2024]
Abstract
Histidine (His) presents a unique challenge for modeling disordered protein conformations, as it is versatile and occurs in both the neutral (His0) and positively charged (His+) states. These His charge states, which are enabled by its imidazole side chain, influence the electrostatic and short-range interactions of His residues, which potentially engage in cation-π, π-π, and charge-charge interactions. Existing coarse-grained (CG) models often simplify His representation by assigning it an average charge, thereby neglecting these potential short-range interactions. To address this gap, we developed a model for intrinsically disordered proteins (IDPs) that accounts for the properties of histidine (H). The resulting IDPH model is a 21-amino acid CG model incorporating both His charge states. We show that interactions involving previously neglected His0 are critical for accurate modeling at high pH, where they significantly influence the compaction of His-rich IDPs such as Histatin-5 and CPEB4. These interactions contribute to structural stabilizations primarily via His0-His0 and His0-Arg interactions, which are overlooked in models focusing solely on the charged His+ state.
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Affiliation(s)
- Rivka Calinsky
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
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Pradhan S, Campanile M, Sharma S, Oliva R, Patra S. Mechanistic Insights into the c-MYC G-Quadruplex and Berberine Binding inside an Aqueous Two-Phase System Mimicking Biomolecular Condensates. J Phys Chem Lett 2024; 15:8706-8714. [PMID: 39159468 DOI: 10.1021/acs.jpclett.4c01806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
We investigated the binding between the c-MYC G-quadruplex (GQ) and berberine chloride (BCl) in an aqueous two-phase system (ATPS) with 12.3 wt % polyethylene glycol and 5.6 wt % dextran, mimicking the highly crowded intracellular biomolecular condensates formed via liquid-liquid phase separation. We found that in the ATPS, complex formation is significantly altered, leading to an increase in affinity and a change in the stoichiometry of the complex with respect to neat buffer conditions. Thermodynamic studies reveal that binding becomes more thermodynamically favorable in the ATPS due to entropic effects, as the strong excluded volume effect inside ATPS droplets reduces the entropic penalty associated with binding. Finally, the binding affinity of BCl for the c-MYC GQ is higher than those for other DNA structures, indicating potential specific interactions. Overall, these findings will be helpful in the design of potential drugs targeting the c-MYC GQ structures in cancer-related biocondensates.
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Affiliation(s)
- Susmita Pradhan
- Department of Chemistry, Birla Institute of Technology and Science-Pilani, Pilani Campus, Pilani 333031, Rajasthan, India
| | - Marco Campanile
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 26, 80126 Naples, Italy
| | - Shubhangi Sharma
- Department of Chemistry, Birla Institute of Technology and Science-Pilani, Pilani Campus, Pilani 333031, Rajasthan, India
| | - Rosario Oliva
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 26, 80126 Naples, Italy
| | - Satyajit Patra
- Department of Chemistry, Birla Institute of Technology and Science-Pilani, Pilani Campus, Pilani 333031, Rajasthan, India
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Pal T, Wessén J, Das S, Chan HS. Differential Effects of Sequence-Local versus Nonlocal Charge Patterns on Phase Separation and Conformational Dimensions of Polyampholytes as Model Intrinsically Disordered Proteins. J Phys Chem Lett 2024; 15:8248-8256. [PMID: 39105804 DOI: 10.1021/acs.jpclett.4c01973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Conformational properties of intrinsically disordered proteins (IDPs) are governed by a sequence-ensemble relationship. To differentiate the impact of sequence-local versus sequence-nonlocal features of an IDP's charge pattern on its conformational dimensions and its phase-separation propensity, the charge "blockiness" κ and the nonlocality-weighted sequence charge decoration (SCD) parameters are compared for their correlations with isolated-chain radii of gyration (Rgs) and upper critical solution temperatures (UCSTs) of polyampholytes modeled by random phase approximation, field-theoretic simulation, and coarse-grained molecular dynamics. SCD is superior to κ in predicting Rg because SCD accounts for effects of contact order, i.e., nonlocality, on dimensions of isolated chains. In contrast, κ and SCD are comparably good, though nonideal, predictors of UCST because frequencies of interchain contacts in the multiple-chain condensed phase are less sensitive to sequence positions than frequencies of intrachain contacts of an isolated chain, as reflected by κ correlating better with condensed-phase interaction energy than SCD.
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Affiliation(s)
- Tanmoy Pal
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jonas Wessén
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Suman Das
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Chemistry, Gandhi Institute of Technology and Management, Visakhapatnam, Andhra Pradesh 530045, India
| | - Hue Sun Chan
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Juković M, Ratkaj I, Kalafatovic D, Bradshaw NJ. Amyloids, amorphous aggregates and assemblies of peptides - Assessing aggregation. Biophys Chem 2024; 308:107202. [PMID: 38382283 DOI: 10.1016/j.bpc.2024.107202] [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: 11/29/2023] [Revised: 01/31/2024] [Accepted: 02/14/2024] [Indexed: 02/23/2024]
Abstract
Amyloid and amorphous aggregates represent the two major categories of aggregates associated with diseases, and although exhibiting distinct features, researchers often treat them as equivalent, which demonstrates the need for more thorough characterization. Here, we compare amyloid and amorphous aggregates based on their biochemical properties, kinetics, and morphological features. To further decipher this issue, we propose the use of peptide self-assemblies as minimalistic models for understanding the aggregation process. Peptide building blocks are significantly smaller than proteins that participate in aggregation, however, they make a plausible means to bridge the gap in discerning the aggregation process at the more complex, protein level. Additionally, we explore the potential use of peptide-inspired models to research the liquid-liquid phase separation as a feasible mechanism preceding amyloid formation. Connecting these concepts can help clarify our understanding of aggregation-related disorders and potentially provide novel drug targets to impede and reverse these serious illnesses.
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Affiliation(s)
- Maja Juković
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia
| | - Ivana Ratkaj
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia
| | - Daniela Kalafatovic
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia.
| | - Nicholas J Bradshaw
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia.
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