Welcome new students: Anezka, Denis and Emil

We are pleased that three new bachelor students, Anezka, Denis and Emil, joined our group. They will strengthen the theoretical&computation part of the group. Denis is dealing with Transition Path Sampling and large-scale simulations of pNIPAM, Emil will focus on Kirkwood-Buff theory of model systems, and Anezka contributes the simulation support of the GACR chromatography project (Dr. Katerina Uselova) at the Faculty of Science, Charles University.
See the group web page for more details.


1 Megahour for phase-separations

model-FES1 080 000 CPU hours were granted in 10th IT4I call for our project entitled: “From single chain collapse to phase separation”. Denis and Vladimir will be in charge of modeling and revealing another from many peculiarities which are observed for PNIPAM.

More details about this IT4I call in Ostrava – link.

Guanidinium salts in the spotlight

Normal salts are well behaved and have uniform action (i.e. in the one direction)  of the collapse-swelling equilibrium. So the more salt we add, the stronger the effect. However, guanidinium thiocyanate (GndSCN) is special and collapses the polymer at first dose, but but reswells the the polymer at higher salt concentrations.Addition-of-salt-and-LCST-2

Our story, which was recently published in JACS was presented at Spring-Meeting of DPG in Dresden 2017 – pdf with presentation.


Colorful effects of guanidinium salts on biomolecules make it to JACS

Already pure guanidinum chloride (GndCl) solution is remarkable. It contains a significant fraction of guanidinium cations in direct contact, a typically rare feature, which is counterintuitive (on electrostatic grounds) link.gndx_toc_jacs

Proteins are unfolded and solutes destabilized in concentrated solutions of GndCl in general. Indeed GndCl is, after urea, the second most common denaturing agent. In the recent article we present different faces of guanidinium action, stabilizing as well as destabilizing which are intimately connected with the anion in action. This work is a joint experimental (spectroscopy & thermodynamics) computational (simulations & theory) study. link