Monte Carlo simulations are used to calculate the binding constant of two Ca2+ ions to the protein bovine calbindin D9k. The change in binding constant with respect to mutation of charged amino acids, presence of various electrolytes, protein concentration, solution pH, and competitive binding of monovalent ions is investigated. Each of these factors may have a large influence on the binding co...

A model of active transport of monovalent cations in mitochondria is developed. The model is based on the coupling of electron transfer to the generation of a metastable protein conformation which in turn leads to the generation of an asymmetric surface charge, a membrane potential, and a redistribution of diffusible ions across the inner mitochondrial membrane. The ions at all times move spont...

A horde of cation-nonselective ion channel clans populate cell membranes. Their number is further augmented by removing extracellular calcium ([Ca 2 ] o ), turning well-behaved Ca 2 -selective channels into less discriminating sieves (Kostyuk and Krishtal, 1977; Almers and McCleskey, 1984). The Ca 2 ion stems the flood of ions moving through many cation channels by lodging in their throats, obs...

Simultaneous occupancy of the two binding sites in gramicidin A by monovalent cations is a well known property of this channel, but the energetic feasibility of this process in molecular dynamics simulations has not been established so far. Here the authors study the energetics of single and double ion occupancy in gramicidin A by constructing the potential of mean force for single and pair of ...

The effect of the simultaneous presence of mono- and divalent cations on the thermodynamics of polyelectrolyte solutions is not fully understood. In physiological conditions, combinations of these ions affect structure formation in biopolymer systems. It is known that divalent counterions form a tight sheath around the polymer backbone, while monovalent ions are distributed in a diffuse cloud. ...

The effective force between two parallel DNA molecules is calculated as a function of their mutual separation for different valencies of counterion and salt ions and different salt concentrations. Computer simulations of the primitive model are used and the shape of the DNA molecules is accurately modeled using different geometrical shapes. We find that multivalent ions induce a significant att...