Exploring the Piezophilic Behavior of Natural Cosolvent Mixtures

Abstract

Marine organisms have evolved a surprising mechanism to counteract the deleterious effects of urea by trimethylammonium N‐oxide (TMAO). The effect of pressure on the structure and intermolecular interactions of lysozyme in urea and TMAO solutions was studied (see picture). These findings help to understand the compensatory effect of urea–TMAO mixtures in deep‐sea organisms.

Cosolvent and Crowding Effects on the Temperature and Pressure Dependent Conformational Dynamics and Stability of Globular Actin

“…Such effect on the stability of the protein may be largely due to indirect, i.e., solvent-mediated interactions of the two agents. 59 High-pressure NMR spectroscopy can be used for technical reasons only in the pressure range up to 2500 bar, where complete denaturation of G-actin does not occur, yet. However, in the lower pressure range additional conformational transitions could be observed.…”

Probing volumetric properties of biomolecular systems by pressure perturbation calorimetry (PPC) – The effects of hydration, cosolvents and crowding

“…Presumably, similar to the effect of polar surface groups of proteins, urea forms a hydration layer that is slightly denser than bulk water [45]. On the other hand, TMAO is known from experimental and molecular dynamics simulation studies to enhance the number of strong hydrogen bonds of the water structure, that is, TMAO serves as ''water structure maker'' [46][47][48][49]. In the presence of proteins, a direct interaction between the protein and the osmolyte is disfavored, and it is the depletion of TMAO from the surface of the protein that gives rise to the increased protein stability as the cosolvent is added [46].…”

“…The data for the 1:2 TMAOurea mixture are located between those of TMAO and urea, indicating their opposite impact on the water structure. Interestingly, the addition of TMAO to urea in a concentration ratio of 1:2 leaves the protein folding equilibrium essentially unaffected, i.e., their stabilizing and destabilizing effect cancel each other largely [46,49]. Moreover, a 1:2 M ratio of TMAO to urea has often been found in deep-sea organisms where the presence of TMAO counteracts the denaturing effect of urea on proteins and allows cells to maintain their cellular function also under high pressure conditions [46,47].…”

“…The adiabatic and isothermal compressibility of the folded protein decrease with Table 1 Results from DSC (unfolding temperature, T m ) and PPC (relative volume change upon unfolding, DV/V) data for the unfolding transition of lysozyme (at pH 7) for various cosolvent concentrations (adopted from Ref. [49]). The maximum estimated error for T m is ±0.2°C, and for DV/V it is 0.004%.…”

How Osmolytes Counteract Pressure Denaturation on a Molecular Scale

“…This can be directly attributed to the relative technical difficulty of high-pressure experiments compared to their high temperature analogues. [37,39–41] However, Winter and coworkers [37,41] have reported experimental data (summarized in Table 1) that can be used directly to calculate the necessary input for the theory resulting in Eq. (2) and (4)–(6).…”