Ionic interactions. Subnanoscale hydrophobic modulation of salt bridges in aqueous media.

Science

Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.

Published: May 2015

Polar interactions such as electrostatic forces and hydrogen bonds play an essential role in biological molecular recognition. On a protein surface, polar interactions occur mostly in a hydrophobic environment because nonpolar amino acid residues cover ~75% of the protein surface. We report that ionic interactions on a hydrophobic surface are modulated by their subnanoscale distance to the surface. We developed a series of ionic head groups-appended self-assembled monolayers with C2, C6, C8, and C12 space-filling alkyl chains, which capture a dendritic guest via the formation of multiple salt bridges. The guest release upon protonolysis is progressively suppressed when its distance from the background hydrophobe changes from 1.2 (C2) to 0.2 (C12) nanometers, with an increase in salt bridge strength of ~3.9 kilocalories per mole.

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aaa7532DOI Listing

Publication Analysis

Top Keywords

ionic interactions
8
salt bridges
8
polar interactions
8
protein surface
8
interactions subnanoscale
4
subnanoscale hydrophobic
4
hydrophobic modulation
4
modulation salt
4
bridges aqueous
4
aqueous media
4

Similar Publications

The development of stable, high-performance electrolytes is essential to addressing the safety concerns and limited lifespan caused by the thermal and chemical instability of traditional organic carbonate-based electrolytes in lithium-ion batteries (LIBs). This study examined the potential of mixed solvent systems, specifically ethyl methyl carbonate (EMC) and tetramethylene sulfone (TMS), to modify ion solvation and improve ionic conductivity in LIB electrolytes. Through molecular dynamics simulations, we investigated the solvation structure and transport properties of lithium ions (Li) in these solvent environments.

View Article and Find Full Text PDF

Developing hydrogels with high conductivity and toughness a facile strategy is important yet challenging. Herein, we proposed a new strategy to develop conductive hydrogels by growing metal dendrites. Water-soluble Sn ions were soaked into the gel and then converted to Sn dendrites an electrochemical reaction; the excessive Sn ions were finally removed by water dialysis, accompanied by dramatic shrinkage of the gel.

View Article and Find Full Text PDF

This study proposes fluorenylmethoxycarbonyl (Fmoc)-protected single amino acids (Fmoc-AAs) as a minimalistic model system to investigate liquid-liquid phase separation (LLPS) and the elusive liquid-to-solid transition of condensates. We demonstrated that Fmoc-AAs exhibit LLPS depending on the pH and ionic strength, primarily driven by hydrophobic interactions. Systematic examination of the conditions under which each Fmoc-AA undergoes LLPS revealed distinct residue-dependent trends in the critical concentrations and phase behavior.

View Article and Find Full Text PDF

Proteins' flexibility is a feature in communicating changes in cell signaling instigated by binding with secondary messengers, such as calcium ions, associated with the coordination of muscle contraction, neurotransmitter release, and gene expression. When binding with the disordered parts of a protein, calcium ions must balance their charge states with the shape of calcium-binding proteins and their versatile pool of partners depending on the circumstances they transmit. Accurately determining the ionic charges of those ions is essential for understanding their role in such processes.

View Article and Find Full Text PDF

ConspectusLithium-ion batteries (LIBs) based on graphite anodes are a widely used state-of-the-art battery technology, but their energy density is approaching theoretical limits, prompting interest in lithium-metal batteries (LMBs) that can achieve higher energy density. In addition, the limited availability of lithium reserves raises supply concerns; therefore, research on postlithium metal batteries is underway. A major issue with these metal anodes, including lithium, is dendritic formation and insufficient reversibility, which leads to safety risks due to short circuits and the use of flammable electrolytes.

View Article and Find Full Text PDF

Want 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!