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Pyo AGT, Zhang Y, Wingreen NS. Proximity to criticality predicts surface properties of biomolecular condensates. Proc Natl Acad Sci U S A 2023; 120:e2220014120. [PMID: 37252985 DOI: 10.1073/pnas.2220014120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
It has recently become appreciated that cells self-organize their interiors through the formation of biomolecular condensates. These condensates, typically formed through liquid-liquid phase separation of proteins, nucleic acids, and other biopolymers, exhibit reversible assembly/disassembly in response to changing conditions. Condensates play many functional roles, aiding in biochemical reactions, signal transduction, and sequestration of certain components. Ultimately, these functions depend on the physical properties of condensates, which are encoded in the microscopic features of the constituent biomolecules. In general, the mapping from microscopic features to macroscopic properties is complex, but it is known that near a critical point, macroscopic properties follow power laws with only a small number of parameters, making it easier to identify underlying principles. How far does this critical region extend for biomolecular condensates and what principles govern condensate properties in the critical regime? Using coarse-grained molecular-dynamics simulations of a representative class of biomolecular condensates, we found that the critical regime can be wide enough to cover the full physiological range of temperatures. Within this critical regime, we identified that polymer sequence influences surface tension predominately via shifting the critical temperature. Finally, we show that condensate surface tension over a wide range of temperatures can be calculated from the critical temperature and a single measurement of the interface width.
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Affiliation(s)
- Andrew G T Pyo
- Department of Physics, Princeton University, Princeton, NJ 08544
| | - Yaojun Zhang
- Department of Physics, Princeton University, Princeton, NJ 08544
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Ned S Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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2
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Aviv M, Cohen-Gerassi D, Orr AA, Misra R, Arnon ZA, Shimon LJW, Shacham-Diamand Y, Tamamis P, Adler-Abramovich L. Modification of a Single Atom Affects the Physical Properties of Double Fluorinated Fmoc-Phe Derivatives. Int J Mol Sci 2021; 22:ijms22179634. [PMID: 34502542 PMCID: PMC8431810 DOI: 10.3390/ijms22179634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022] Open
Abstract
Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.
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Affiliation(s)
- Moran Aviv
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; (M.A.); (D.C.-G.); (R.M.); (Z.A.A.)
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- The Center for the Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
- School of Mechanical Engineering, Afeka Tel Aviv Academic College of Engineering, Tel Aviv 6910717, Israel
| | - Dana Cohen-Gerassi
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; (M.A.); (D.C.-G.); (R.M.); (Z.A.A.)
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- The Center for the Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 6997801, Israel;
| | - Asuka A. Orr
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA; (A.A.O.); (P.T.)
| | - Rajkumar Misra
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; (M.A.); (D.C.-G.); (R.M.); (Z.A.A.)
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- The Center for the Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Zohar A. Arnon
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; (M.A.); (D.C.-G.); (R.M.); (Z.A.A.)
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- The Center for the Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Linda J. W. Shimon
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76132701, Israel;
| | - Yosi Shacham-Diamand
- Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 6997801, Israel;
- Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
- TAU/TiET Food Security Center of Excellence (T2FSCoE), Thapar Institute of Engineering and Technology, Patiala 147004, India
| | - Phanourios Tamamis
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA; (A.A.O.); (P.T.)
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843-3003, USA
| | - Lihi Adler-Abramovich
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; (M.A.); (D.C.-G.); (R.M.); (Z.A.A.)
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- The Center for the Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
- Correspondence:
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Saikia C, Dym O, Altman-Gueta H, Gordon D, Reuveny E, Karbat I. A Molecular Lid Mechanism of K + Channel Blocker Action Revealed by a Cone Peptide. J Mol Biol 2021; 433:166957. [PMID: 33771569 DOI: 10.1016/j.jmb.2021.166957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 12/15/2022]
Abstract
Many venomous organisms carry in their arsenal short polypeptides that block K+ channels in a highly selective manner. These toxins may compete with the permeating ions directly via a "plug" mechanism or indirectly via a "pore-collapse" mechanism. An alternative "lid" mechanism was proposed but remained poorly defined. Here we study the Drosophila Shaker channel block by Conkunitzin-S1 and Conkunitzin-C3, two highly similar toxins derived from cone venom. Despite their similarity, the two peptides exhibited differences in their binding poses and biophysical assays, implying discrete action modes. We show that while Conkunitzin-S1 binds tightly to the channel turret and acts via a "pore-collapse" mechanism, Conkunitzin-C3 does not contact this region. Instead, Conk-C3 uses a non-conserved Arg to divert the permeant ions and trap them in off-axis cryptic sites above the SF, a mechanism we term a "molecular-lid". Our study provides an atomic description of the "lid" K+ blocking mode and offers valuable insights for the design of therapeutics based on venom peptides.
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Affiliation(s)
- Chandamita Saikia
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Orly Dym
- Structural Proteomic Unit, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hagit Altman-Gueta
- Department of Plant Molecular Biology and Ecology, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Dalia Gordon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Reuveny
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Izhar Karbat
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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Nayak A, Kumar S, Singh SP, Bhattacharyya A, Dixit A, Roychowdhury A. Oncogenic potential of ATAD2 in stomach cancer and insights into the protein-protein interactions at its AAA + ATPase domain and bromodomain. J Biomol Struct Dyn 2021; 40:5606-5622. [PMID: 33438526 DOI: 10.1080/07391102.2021.1871959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
ATAD2 has recently been shown to promote stomach cancer. However, nothing is known about the functional network of ATAD2 in stomach carcinogenesis. This study illustrates the oncogenic potential of ATAD2 and the participation of its ATPase and bromodomain in stomach malignancy. Expression of ATAD2 in stomach cancer is analyzed by in silico and in vitro techniques including western blot and immunofluorescence microscopy of stomach cancer cells (SCCs) and tissues. The oncogenic potential of ATAD2 is examined thoroughly using genetic alterations, driver gene prediction, survival analysis, identification of interacting partners, and analysis of canonical pathways. To understand the protein-protein interactions (PPI) at residue level, molecular docking and molecular dynamics simulations (1200 ns) are performed. Enhanced expression of ATAD2 is observed in H. pylori-infected SCCs, patient biopsy tissues, and all stages and grades of stomach cancer. High expression of ATAD2 is found to be negatively correlated with the survival of stomach cancer patients. ATAD2 is a cancer driver gene with 37 mutational sites and a predictable factor for stomach cancer prognosis with high accuracy. The top canonical pathways of ATAD2 indicate its participation in stomach malignancy. The ATAD2-PPI in stomach cancer identify top-ranked partners; ESR1, SUMO2, SPTN2, and MYC show preference for the bromodomain whereas NCOA3 and HDA11 have preference for the ATPase domain of ATAD2. The oncogenic characterization of ATAD2 provides strong evidence to consider ATAD2 as a stomach cancer biomarker. These studies offer an insight for the first time into the ATAD2-PPI interface presenting a novel target for cancer therapeutics. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Aditi Nayak
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, India
| | - Sugandh Kumar
- Institute of Life Sciences, Bhubaneswar, Odisha, India
| | | | - Asima Bhattacharyya
- School of Biological Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, HBNI, Khurda, Odisha, India
| | | | - Anasuya Roychowdhury
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, India
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Požar M, Jukić I, Lovrinčević B. Thermodynamic, structural and dynamic properties of selected non-associative neat liquids. J Phys Condens Matter 2020; 32:405101. [PMID: 32412441 DOI: 10.1088/1361-648x/ab935d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
Non-associative neat liquids benzene, acetone and carbon tetrachloride have been examined via molecular dynamics simulations. Several models of each neat liquid have been simulated, and selected thermodynamic and structural results are presented. However, the models have been compared mainly in terms of their dynamic quantities. Since models are rarely parametrized with the dynamic properties in mind, the principal goal of this work is to present quantities such as the power spectra, rotational correlation functions and relaxation times, diffusion coefficients and self and distinct parts of the van Hove functions in relation to available experimental data. The general trends of the calculated data provide a benchmark for the behavior of neat simple liquids which will be built upon in the cases of mixtures with associative liquids.
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Affiliation(s)
- Martina Požar
- University of Split, Faculty of Science, Rud-era Boškovića 33, 21000 Split, Croatia
| | - Ivo Jukić
- University of Split, Faculty of Science, Rud-era Boškovića 33, 21000 Split, Croatia
| | - Bernarda Lovrinčević
- University of Split, Faculty of Science, Rud-era Boškovića 33, 21000 Split, Croatia
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Löw H, Mena-Osteritz E, Mullen KM, Jäger CM, von Delius M. Self-Assembly, Adaptive Response, and in,out-Stereoisomerism of Large Orthoformate Cryptands. Chempluschem 2020; 85:1008-1012. [PMID: 32347636 DOI: 10.1002/cplu.202000254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/16/2020] [Indexed: 12/19/2022]
Abstract
We report on triethylene glycol-based orthoformate cryptands, which adapt their bridgehead configurations in response to metal templates and intramolecular hydrogen bonding in a complex manner. In contrast to smaller 1.1.1-orthoformate cryptands, the inversion from out,out-2.2.2 to in,in-2.2.2 occurs spontaneously by thermal homeomorphic isomerization, i. e., without bond breakage. The global thermodynamic minimum of the entire network, which includes an unprecedented third isomer (in,out-2.2.2), could only be reached under conditions that facilitate dynamic covalent exchange. Both inversion processes were studied in detail, including DFT calculations and MD simulations, which were particularly helpful for explaining differences between equilibrium compositions in solvents chloroform and acetonitrile. Unexpectedly, the system could be driven to the in,out-2.2.2 state by using a metal template with a size mismatch with respect to the out,out-2.2.2 cage.
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Affiliation(s)
- Henrik Löw
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Elena Mena-Osteritz
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Kathleen M Mullen
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, 4001, Australia
| | - Christof M Jäger
- Department of Chemical and Environmental Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Max von Delius
- Institute of Organic Chemistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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Li H, Francisco JS, Zeng XC. Unraveling the mechanism of selective ion transport in hydrophobic subnanometer channels. Proc Natl Acad Sci U S A 2015; 112:10851-6. [PMID: 26283377 DOI: 10.1073/pnas.1513718112] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently reported synthetic organic nanopore (SONP) can mimic a key feature of natural ion channels, i.e., selective ion transport. However, the physical mechanism underlying the K(+)/Na(+) selectivity for the SONPs is dramatically different from that of natural ion channels. To achieve a better understanding of the selective ion transport in hydrophobic subnanometer channels in general and SONPs in particular, we perform a series of ab initio molecular dynamics simulations to investigate the diffusivity of aqua Na(+) and K(+) ions in two prototype hydrophobic nanochannels: (i) an SONP with radius of 3.2 Å, and (ii) single-walled carbon nanotubes (CNTs) with radii of 3-5 Å (these radii are comparable to those of the biological potassium K(+) channels). We find that the hydration shell of aqua Na(+) ion is smaller than that of aqua K(+) ion but notably more structured and less yielding. The aqua ions do not lower the diffusivity of water molecules in CNTs, but in SONP the diffusivity of aqua ions (Na(+) in particular) is strongly suppressed due to the rugged inner surface. Moreover, the aqua Na(+) ion requires higher formation energy than aqua K(+) ion in the hydrophobic nanochannels. As such, we find that the ion (K(+) vs. Na(+)) selectivity of the (8, 8) CNT is ∼20× higher than that of SONP. Hence, the (8, 8) CNT is likely the most efficient artificial K(+) channel due in part to its special interior environment in which Na(+) can be fully solvated, whereas K(+) cannot. This work provides deeper insights into the physical chemistry behind selective ion transport in nanochannels.
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Abstract
In order to elucidate how phosphatidylserine (PS6) interacts with AQP5 in a cell membrane, we developed a hybrid steered molecular dynamics (hSMD) method that involved: (1) Simultaneously steering two centers of mass of two selected segments of the ligand, and (2) equilibrating the ligand-protein complex with and without biasing the system. Validating hSMD, we first studied vascular endothelial growth factor receptor 1 (VEGFR1) in complex with N-(4-Chlorophenyl)-2-((pyridin-4-ylmethyl)amino)benzamide (8ST), for which the binding energy is known from in vitro experiments. In this study, our computed binding energy well agreed with the experimental value. Knowing the accuracy of this hSMD method, we applied it to the AQP5-lipid-bilayer system to answer an outstanding question relevant to AQP5's physiological function: Will the PS6, a lipid having a single long hydrocarbon tail that was found in the central pore of the AQP5 tetramer crystal, actually bind to and inhibit AQP5's central pore under near-physiological conditions, namely, when AQP5 tetramer is embedded in a lipid bilayer? We found, in silico, using the CHARMM 36 force field, that binding PS6 to AQP5 was a factor of 3 million weaker than "binding" it in the lipid bilayer. This suggests that AQP5's central pore will not be inhibited by PS6 or a similar lipid in a physiological environment.
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Affiliation(s)
- Liao Y Chen
- Department of Physics, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas , USA
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