DNA displays a richness of biologically relevant supramolecular structures, which depend on both sequence and ambient conditions. The effect of dragging double-stranded DNA (dsDNA) from water into poor solvent on the double-stranded structure is still unclear because of condensation. Here, we employed single molecule techniques based on atomic force microscopy and molecular dynamics (MD) simulations to investigate the change in structure and mechanics of DNA during the ambient change. We found that the two strands are split apart when the dsDNA is pulled at one strand from water into a poor solvent. The findings were corroborated by MD simulations where dsDNA was dragged from water into poor solvent, revealing details of the strand separation at the water/poor solvent interface. Because the structure of DNA is of high polarity, all poor solvents show a relatively low polarity. We speculate that the principle of spontaneous unwinding/splitting of dsDNA by providing a low-polarity (in other word, hydrophobic) micro-environment is exploited as one of the catalysis mechanisms of helicases.
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http://dx.doi.org/10.1021/ja074776c | DOI Listing |
Int J Biol Macromol
January 2025
Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.
The inherent heterogeneity, poor compatibility with polymers, and dark color of lignin limit its application in composites. In this study, original lignin (OL) was fractionated sequentially using four green organic solvents to obtain lignin fractions with different chemical structures. These well-defined lignin fractions were then blended with polybutylene succinate (PBS) to fabricate biocomposites.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
South China Normal University, Chemistry, 55 W Zhongshan Rd, 510006, Guangzhou, CHINA.
Lithium-sulfur (Li-S) batteries has been regarded as one of the most promising next-generation energy storage systems due to their high theoretical energy density. However, the practical application of Li-S batteries is still hindered by the unstable cathode-electrolyte interphase and the early passivation of charge product (Li2S), leading to poor cycling stability and low S utilization. Herein, we propose an electrolyte engineering strategy using highly solvating hexamethylphosphoramide (HMPA) as a co-solvent to elucidate the dissociation-precipitation chemistry of lithium polysulfides (LiPSs).
View Article and Find Full Text PDFChem Sci
January 2025
School of Materials and Energy, University of Electronic Science and Technology of China Chengdu 611731 China
Silicon (Si) is considered a promising anode material for next-generation lithium-ion batteries due to its high theoretical specific capacity and earth-abundancy. However, challenges such as significant volume expansion, unstable solid electrolyte interphase (SEI) formation in incompatible electrolytes, and slow lithium-ion transport lead to its poor cycling and rate performance. In this work, it is demonstrated that superior cyclability and rate capability of Si anodes can be achieved using ethyl fluoroacetate (EFA) and fluoroethylene carbonate (FEC) solvents with low binding energy with Li but with sufficiently high relative dielectric constants.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
CO capture is an important process for mitigating CO emissions in the atmosphere. Recently, ionic liquids have been identified as possible systems for CO capture processes. Major drawbacks of such systems are mostly in the high cost of synthesis of such liquids and poor biodegradability.
View Article and Find Full Text PDFCurr Org Synth
January 2025
Laboratoire de Chimie Organique (LR17ES08), Faculté des Sciences de Sfax, University of Sfax, Route de Soukra Km 3.5, BP 1171, 3000, Sfax, Tunisia.
Aim And Objective: It is well established that 4H-pyran derivatives hold a significant position in synthetic organic chemistry due to their diverse biological and pharmacological properties. This work aims to introduce a novel synthetic pathway for highly functionalized 4H-pyran derivatives, achieved through a 1,4-Michael addition followed by a cascade cyclization. This reaction is catalyzed by LiOH·H2O under ultrasonic irradiation in water, offering an efficient and environmentally friendly approach.
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