The reentrant condensation of 21-bp oligonucleotide in the presence of spermidine was investigated by laser light scattering and capillary electrophoresis. 21-bp oligonucleotide showed a bimodal distribution in 1 × TE buffer, with the slow mode being the characteristic diffusion of polyelectrolyte in solution without enough salt. At the fixed spermidine concentration, the reentry of oligonucleotide underwent aggregation, phase separation, and disassociation in sequence with time, and the kinetics was extremely slow. For example, it took more than 1200 h (50 days) for the reentry to complete at 21 mM spermidine. Higher spermidine concentration led to faster kinetics. After reentry, the slow mode disappeared, and the charges of oligonucleotide were at least partially neutralized. No prominent charge inversion was observed. The kinetics of oligonucleotide reentry in the presence of spermidine gained insight in the interactions of polyelectrolyte in aqueous solution.
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http://dx.doi.org/10.1021/jp1074187 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Manufacture Science and Engineering, Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China.
Ice accretion caused by freezing rain or snowstorms is a common phenomenon in cold climates that seriously threatens the safety and reliability of telecommunication lines and other overhead networks. Various anti-icing strategies have been demonstrated through surface engineering to delay ice formation. However, existing anti-icing surfaces still encounter several challenges; for example, surfaces are prone to ice-pinning formation due to the impact of supercooled droplets, which leads to a loss of anti-icing effectiveness.
View Article and Find Full Text PDFJ Mol Biol
December 2024
Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 38000, Grenoble, France. Electronic address:
Rabies virus (RABV) generates membrane-less liquid organelles (Negri bodies) in the cytoplasm of its host cell, where genome transcription and replication and nucleocapsid assembly take place, but the mechanisms of their assembly and maturation remain to be explained. An essential component of the viral RNA synthesizing machine, the phosphoprotein (P), acts as a scaffold protein for the assembly of these condensates. This intrinsically disordered protein forms star-shaped dimers with N-terminal negatively charged flexible arms and C-terminal globular domains exhibiting a large dipole moment.
View Article and Find Full Text PDFBiochemistry
November 2024
Tata Institute of Fundamental Research Hyderabad 36/P Gopanapally village, Hyderabad, Telangana India 500046.
Within the framework of liquid-liquid phase separation (LLPS), biomolecular condensation orchestrates vital cellular processes, and its dysregulation is implicated in severe pathological conditions. Recent studies highlight the role of intrinsically disordered proteins (IDPs) in LLPS, yet the influence of microenvironmental factors has remained a puzzling factor. Here, via computational simulation of the impact of solution conditions on LLPS behavior of neurologically pathogenic IDP Aβ40, we chanced upon a salt-driven reentrant condensation phenomenon, wherein Aβ40 aggregation increases with low salt concentrations (25-50 mM), followed by a decline with further salt increments.
View Article and Find Full Text PDFNat Commun
October 2024
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
The inorganic biopolymer polyphosphate (polyP) occurs in all domains of life and affects myriad cellular processes. A longstanding observation is polyP's frequent proximity to chromatin, and, in many bacteria, its occurrence as magnesium (Mg)-enriched condensates embedded in the nucleoid region, particularly in response to stress. The physical basis of the interaction between polyP, DNA and Mg, and the resulting effects on the organization of the nucleoid and polyP condensates, remain poorly understood.
View Article and Find Full Text PDFBiomacromolecules
November 2024
Department of Molecules & Materials, MESA+ Institute, University of Twente, AE 7500 Enschede, the Netherlands.
We explore the reentrant condensation of polyelectrolytes triggered by multivalent salts, whose phase-transition mechanism remains under debate. We propose a theory to study the reentrant condensation, which separates the electrostatic effect into two parts: a short-range electrostatic gluonic effect because of sharing of multivalent ions by ionic monomers and a long-range electrostatic correlation effect from all ions. The theory suggests that the electrostatic gluonic effect governs reentrant condensation, requiring a minimum coupling energy to initiate the phase transition.
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