Using MD simulations, we study ion-ion interactions in water. We study the potentials of mean force for the full set of alkali halide ion pairs, and we test different parameter sets for modeling the water and the ions. We also calculate association equilibrium constants and compare them to experiments. From observations on the relative depths of the free energies of the contact and the solvent-shared ion pair, we find a good correlation with Collins proposition: two small and two large ions should associate in water, and small-large combination of ions should be more dissociated.
COBISS.SI-ID: 30430213
This work presented Monte Carlo and integral equation studies of the contribution of the solvent to the force between the colloidal particles. The effective inter-colloidal force showed oscillatory repulsive and attractive character with the period equal to the diameter of the solvent molecules. At sufficient strength of the inter-particle attractive interactions, these oscillations disappeared, the force becoming long-ranged and attractive at all separations. These results are very important for the understanding of the stability of colloidal dispersions.
COBISS.SI-ID: 30270469
Gyrase, an essential bacterial topoisomerase, is the target of several antibiotics as well as of bacterial toxin CcdB. This toxin poisons gyrase by causing inhibition of both transcription and replication of DNA. Since the molecular driving forces of gyrase unfolding and CcdB:gyrase binding were unknown we performed a detailed thermodynamic analysis of these processes. The dissection of energetics suggests that the CcdB:gyrase recognition is accompanied by extensive structural rearrangements of gyrase which is in accordance with the proposed structural model of CcdB:gyrase binding.
COBISS.SI-ID: 30725381
The role of the polyion's charge density and the nature of the counterions has been investigated using the dielectric relaxation spectroscopy. The results presented in this contribution combined with insights from existing experimental and theoretical studies lead us to the conclusion that fluoride counterions were to a lesser extent affected by the polyion than bromide counterions.
COBISS.SI-ID: 30525189
We perform isothermal-isobaric Monte Carlo simulations on the 3D MB model of water. An additional purpose of this work is to develop and test Wertheim’s Ornstein–Zernike integral equation and thermodynamic perturbation theories. The two analytical approaches are orders of magnitude more efficient than simulations. The ultimate goal is to develop statistical mechanical theory that can efficiently predict the properties of systems of orientation-dependent molecules, such as water.
COBISS.SI-ID: 33405957