Crowders and Cosolvents—Major Contributors to the Cellular Milieu and Efficient Means to Counteract Environmental Stresses

Abstract

The free energy and conformational landscape of biomolecular systems as well as biochemical reactions depend not only on temperature and pressure, but also on the particular solution conditions. Such conditions include the effects of cosolvents (for example osmolytes) and macromolecular crowding, which are crucial components to understand the energetics and kinetics of biological processes in living system. Such conditions are also important for the understanding of many debilitating diseases, such as those where misfolding and amyloid formation of proteins are involved. Moreover, understanding their effects on biomolecular processes is prerequisite for designing industrially relevant enzymatic reactions, which seldom take place under neat conditions. Here, we review and discuss experimental and theoretical studies on the characterization of cosolvent and crowding induced effects in biologically relevant systems, approaching even the complexity of living organisms. In particular, we focus on cosolvent and crowding effects on the conformational equilibrium and folding kinetics of proteins and nucleic acids as well as on enzymatic reactions, including their effects on the temperature and pressure dependence of these processes. By presenting a few representative examples, we show how such effects are unveiled and described in thermodynamic and kinetic terms.

Choline Chloride as a Nano‐Crowder Protects HP‐36 from Urea‐Induced Denaturation: Insights from Solvent Dynamics and Protein‐Solvent Interactions

“…The findings of this investigation summarize that the role of the bulky choline ion can be viewed as that of a nano‐crowder, which suppresses the dynamics of the protein and the other co‐solvents, thereby preventing the unfolding. The role of choline can be compared to the role of another osmolyte TMAO, which also acts as a crowding agent and results in entropic stabilization of the protein . Due to this effect, TMAO has been often referred to as nano‐crowder also.…”

“…The role of choline can be compared to the role of another osmolyte TMAO, which also acts as a crowding agent and results in entropic stabilization of the protein. [12,93] Due to this effect, TMAO has been often referred to as nano-crowder also. We hope that the current work is extremely useful in understanding the role of protecting osmolytes at the microscopic level and will contribute to designing potential candidates for this purpose.…”

Temperature, Hydrostatic Pressure, and Osmolyte Effects on Liquid–Liquid Phase Separation in Protein Condensates: Physical Chemistry and Biological Implications

“…[1][2][3][4][5] The interior of ab iological cell, for example, is an extraordinarily crowded environment, consisting of nucleic acids, polysaccharides,p roteins, ribonucleoproteins, etc. [4][5][6] Cases in point include red blood cells, which contain about 35 %p rotein by weight, and eye lens cells, which containu pt o 60 %p rotein. Proteini nteractions that lead to condensed or aggregated states also play crucial roles in many diseases, including cataracts, sickle cell anemia, and amyloidosis (e.g.…”

Printing Life‐Inspired Subcellular Scale Compartments with Autonomous Molecularly Crowded Confinement

“…The above different size regimes from the pL to the aL scale are expected to present distinct physicochemical features also in connection to their different surface/volume ratios. Focusing on the subcellular systems with more complex activities, different biomacromolecules (DNA, proteins, enzymes) are highly crowded occupying a large part of the compartment volume . Crowding may induce volume exclusion, i.e., limited accessible space and available water molecules for biomolecules .…”

“…Focusing on the subcellular systems with more complex activities, different biomacromolecules (DNA, proteins, enzymes) are highly crowded occupying a large part of the compartment volume . Crowding may induce volume exclusion, i.e., limited accessible space and available water molecules for biomolecules . Moreover, crowding is often associated to confinement effects, as evolution has selected the spatial localization of fundamental processes by spontaneous phase separation processes .…”