Single channel recordings were used to determine the effect of direct electrostatic interactions between sulfonate-coated gold nanoparticles and the constriction of the Staphylococcus aureus α-hemolysin protein channel on the ionic current amplitude. We provide evidence that Lys147 of α-hemolysin can interact with the sulfonate groups at the nanoparticle surface, and these interactions can reversibly block 100% of the residual ionic current. Lys147 is normally involved in a salt bridge with Glu111. The capture of a nanoparticle leads to a partial current block at neutral pH values, but protonation of Glu111 at pH 2.8 results in a full current block when the nanoparticle is captured. At pH 2.8, we suggest that Lys147 is free to engage in electrostatic interactions with sulfonates at the nanoparticle surface. To verify our results, we engineered a mutation in the α-hemolysin protein, where Glu111 is substituted by Ala (E111A), thus removing Glu111-Lys147 interactions and facilitating Lys147-sulfonate electrostatic interactions. This mutation leads to a 100% current block at pH 2.8 and a 92% block at pH 8.0, showing that electrostatic interactions are formed between the nanopore and the nanoparticle surface. Besides demonstrating the effect of electrostatic interactions on cross channel ionic current, this work offers a novel approach to controlling open and closed states of the α-hemolysin nanopore as a function of external gears.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/la302613g | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Computational Modeling of Electrocatalysts for CO Reduction: Probing the Role of Primary, Secondary, and Outer Coordination Spheres.
Acc Chem Res
January 2025
The Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
ConspectusIn the search for efficient and selective electrocatalysts capable of converting greenhouse gases to value-added products, enzymes found in naturally existing bacteria provide the basis for most approaches toward electrocatalyst design. Ni,Fe-carbon monoxide dehydrogenase (Ni,Fe-CODH) is one such enzyme, with a nickel-iron-sulfur cluster named the C-cluster, where CO binds and is converted to CO at high rates near the thermodynamic potential. In this Account, we divide the enzyme's catalytic contributions into three categories based on location and function.
View Article and Find Full Text PDFBoosting Cu ion capture in high-salinity environments with amino-functionalized millispheres.
Nanoscale
January 2025
College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China.
High salinity in wastewater often hampers the performance of traditional adsorbents by disrupting electrostatic interactions and ion exchange processes, limiting their efficiency. This study addresses these challenges by investigating the salt-promoted adsorption of Cu ions onto amino-functionalized chloromethylated polystyrene (EDA@CMPS) millispheres. The adsorbent was synthesized by grafting ethylenediamine (EDA) onto CMPS, which significantly improved Cu adsorption, achieving nearly three times the capacity in saline solutions (1.
View Article and Find Full Text PDFExtending Badger's rule. I. The relationship between energy and structure in hydrogen bonds.
J Chem Phys
January 2025
Department of Chemistry, University of Washington, Seattle, Washington 98185, USA.
We derive a new expression for the strength of a hydrogen bond (VHB) in terms of the elongation of the covalent bond of the donor fragment participating in the hydrogen bond (ΔrHB) and the intermolecular coordinates R (separation between the heavy atoms) and θ (deviation of the hydrogen bond from linearity). The expression includes components describing the covalent D-H bond of the hydrogen bond donor via a Morse potential, the Pauli repulsion, and electrostatic interactions between the constituent fragments using a linear expansion of their dipole moment and a quadratic expansion of their polarizability tensor. We fitted the parameters of the model using ab initio electronic structure results for six hydrogen bonded dimers, namely, NH3-NH3, H2O-H2O, HF-HF, H2O-NH3, HF-H2O, and HF-NH3, and validated its performance for extended parts of their potential energy surfaces, resulting in a mean absolute error ranging from 0.
View Article and Find Full Text PDFInterfacial Adsorption Interactions of Dyes and Chitosan/Activated Carbon@Curcumin Derivatives in Single-Component and Binary Solutions.
Langmuir
January 2025
Hephaestus Laboratory, School of Chemistry, Faculty of Sciences, Democritus University of Thrace, GR-65404 Kavala, Greece.
The remediation of wastewaters contaminated with dyes (discharged mainly from industry) is very important for preserving environmental quality and human health. In this study, a new composite chitosan (CS)-based adsorbent combined with activated carbon (AC) and curcumin (Cur) (abbreviated hereafter as CS/AC@Cur) in three different ratios (12.5%, 25%, and 50%) was synthesized for the removal of anionic [reactive black 5 (RB5)] and cationic [methylene blue (MB)] dyes in single-component or binary systems.
View Article and Find Full Text PDF[The many ways flowers send signals to pollinators].
Biol Aujourdhui
January 2025
Institut d'Écologie et des Sciences de l'Environnement de Paris (iEES Paris), Paris, France - Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
The evolutionary success of angiosperms, which make up more than 95 percent of the world's terrestrial flora, is largely based on their interactions with animal pollinators. Indeed, it is estimated that, on average, 87.5 percent of flowering plants are pollinated by animals.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!