Local solvation structures govern the mixing thermodynamics of glycerol–water solutions

Abstract

Glycerol is a major cryoprotective agent and is widely used to promote protein stabilization. Through a combined experimental and theoretical study, we show that global thermodynamic mixing properties of glycerol...

Impact of hydrophobicity on local solvation structures and its connection with the global solubilization thermodynamics of amphiphilic molecules

“…36 The second peak appearing at ∼550 cm −1 characterises the bound water population in the solution which directly are H-bonded to the hydrophilic (–OH) part of the alcohol(s). 25 The peak frequencies are found to change as a function of X w (Fig. 1(c) and (d)).…”

“…12,[22][23][24] Our primary objective is to establish a connection between the influence of polarity on the local solvation properties (microscopic) and the role of these local hydration motifs in governing the overall mixing (solubilization) thermodynamics. 25 We analyse the THz spectral fingerprints of local hydration structures and their associated ultrafast dynamics using THz time domain spectroscopic (TTDS) measurements. Additionally, we perform MD simulations of these aqueous solutions to gain a microscopic perspective on solvation structures.…”

Hydration makes a difference! How to tune protein complexes between liquid–liquid and liquid–solid phase separation

“…contribution (y-axis) we use the slope (Da/Dn) obtained by linearly fitting the Da increase/decrease in the 400-650 cm À1 frequency range, previously demonstrated to be the best choice to quantify the contribution in a robust and transferable way. 8,27,28,31,32,34 Each point in the THz phase diagram corresponds to a measured sample. Non phase-separating systems provide points close to (0,0), by construction.…”

“…Therefore, such constant correlation factors are general and system independent, as detailed in previous works. 31,32,36 The negative sign of D % S wrap , combined with the negative amplitude, i.e. Da wrap o 0 of the wrap spectroscopic population, already tells us that the release of cavity-wrap water into the diluted phase provides a hydration driving force for phase separation, as it increases the entropy.…”

“…For bound water, the steric constraints in water rotational motions induced by the proximity to and direct H-bonding with the solutes cause a reduction in the amplitude of soft librational modes and an increase in that of hard librations, resulting in a characteristic Da linear increase in the 4400 cm À1 frequency range. 31,32 The combination of these two observables is characteristic of the occurrence of LLPS. 8,11 In order to understand what makes the difference between forming either liquid condensates or solid aggregates, we here focus on the cellular prion protein (PrP), which can be driven to undergo LLPS vs. LSPS with few mutations.…”