Cation-assisted interactions between N-containing heterocycles (NHCs) and CO2 have been systematically studied by using density functional theory (DFT). For neutral and anionic (non-carbenoid) NHCs, the effects of monovalent cations (i.e., alkali metal ions) are moderate to small (the NHC-CO2 binding energy change, ΔBE usually < 25 kJ mol(-1)). However, for NHC carbenes, due to their strong bas...

Structured RNA molecules play roles in central biological processes and understanding the basic forces and features that govern RNA folding kinetics and thermodynamics can help elucidate principles that underlie biological function. Here we investigate one such feature, the specific interaction of monovalent cations with a structured RNA, the P4-P6 domain of the Tetrahymena ribozyme. We employ ...

We have investigated the reduction of steady state sodium channel currents by a monovalent and a divalent guanidinium analogue. The amount of block by the divalent compound at a constant membrane potential was dramatically reduced by an increase in the internal salt concentration. Channel block by the monovalent molecule was a less steep function of salt concentration. These results would be ex...

The effects of monovalent (Na, K) and divalent (Mg, Ca, Mn) ions on the interaction between DNA and histone are studied using the molecular combing technique. λ-DNA molecules and DNA-histone complexes incubated with metal cations (Na, K, Mg, Ca, Mn) are stretched on hydrophobic surfaces, and directly observed by fluorescence microscopy. The results indicate that when these cations are added int...

Adsorption of monovalent and multivalent cat-and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple ...

In a combined experimental and theoretical study, we show that capacitive charging of porous electrodes in multicomponent electrolytes may lead to the phenomenon of time-dependent ion selectivity of the electrical double layers (EDLs) in the electrodes. This effect is found in experiments on capacitive deionization of water containing NaCl/CaCl(2) mixtures, when the concentration of Na(+) ions ...

The mechanisms underlying ion transport and selectivity in calcium channels are examined using electrostatic calculations and Brownian dynamics simulations. We model the channel as a rigid structure with fixed charges in the walls, representing glutamate residues thought to be responsible for ion selectivity. Potential energy profiles obtained from multi-ion electrostatic calculations provide i...