Knowledge of the mechanisms of interaction between self-aggregating peptides and nucleic acids or other polyanions is key to the understanding of many aggregation processes underlying several human diseases (e.g., Alzheimer's and Parkinson's diseases). Determining the affinity and kinetic steps of such interactions is challenging due to the competition between hydrophobic self-aggregating forces and electrostatic binding forces. Kahalalide F (KF) is an anticancer hydrophobic peptide that contains a single positive charge that confers strong aggregative properties with polyanions. This makes KF an ideal model to elucidate the mechanisms by which self-aggregation competes with binding to a strongly charged polyelectrolyte such as DNA. We use optical tweezers to apply mechanical forces to single DNA molecules and show that KF and DNA interact in a two-step kinetic process promoted by the electrostatic binding of DNA to the aggregate surface followed by the stabilization of the complex due to hydrophobic interactions. From the measured pulling curves we determine the spectrum of binding affinities, kinetic barriers, and lengths of DNA segments sequestered within the KF-DNA complex. We find there is a capture distance beyond which the complex collapses into compact aggregates stabilized by strong hydrophobic forces and discuss how the bending rigidity of the nucleic acid affects this process. We hypothesize that within an in vivo context, the enhanced electrostatic interaction of KF due to its aggregation might mediate the binding to other polyanions. The proposed methodology should be useful to quantitatively characterize other compounds or proteins in which the formation of aggregates is relevant.
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http://dx.doi.org/10.1021/nn4007237 | DOI Listing |
Molecules
January 2025
Dipartimento di Scienze Matematiche, Informatiche e Fisiche (DMIF), University of Udine, 33100 Udine, Italy.
(1) Background: Electrostatics plays a capital role in protein-protein and protein-ligand interactions. Implicit solvent models are widely used to describe electrostatics and complementarity at interfaces. Electrostatic complementarity at the interface is not trivial, involving surface potentials rather than the charges of surfacial contacting atoms.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030032, China.
The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group dl-alanine to synthesise a water-soluble Al fluorescent probe (Probe A).
View Article and Find Full Text PDFJ Adv Res
January 2025
State Key Laboratory of Chemical Biology and Drug Discovery and the Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Shenzhen Key Laboratory for Food Biological Safety Control, Food Safety and Technology Research Centre, The Hong Kong PolyU Shenzhen Research Institute, Shenzhen, PR China. Electronic address:
Introduction: Infections stemming from multidrug-resistant bacteria present a substantial threat to public health today. Discovering or synthesizing novel compounds is crucial to alleviate this pressing situation.
Objective: The main purpose of this study is to verify the antibacterial activity of LTX-315 and explore its primary action mode.
Chem Biol Interact
January 2025
College of Chemistry and Materials, Jiangxi Normal University, Nanchang, 330022, China. Electronic address:
As a replacement of bisphenol A, bisphenol S (BPS) is commonly used in the wrappers and food containers of daily life. Epidemiological studies demonstrate a close link between BPS exposure and vascular diseases, where the biological activities of BPS remain scarcely known. Herein, the effects of BPS on endothelial function as well as the underlying mechanism were investigated in human umbilical vein endothelial cells (HUVECs) and mouse arteries.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Life Science, Northwest A&F University, Yangling 712100, China. Electronic address:
Amycolatopsis sp. BJA-103 was isolated for its exceptional feather-degradation capability, leading to the purification, cloning, and heterologous expression of the keratinase enzyme, KER0199. Sequence analysis places KER0199 within the S8 protease family, revealing <60 % sequence similarity to known proteases.
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