Abstract
Macromolecular crowding is known to affect protein folding, binding of small molecules, interaction with nucleic acids, enzymatic activity, protein-protein interactions, and protein aggregation. Although for a long time it was believed that the major mechanism of the action of crowded environments on structure, folding, thermodynamics, and function of a protein can be described in terms of the excluded volume effects, it is getting clear now that other factors originating from the presence of high concentrations of “inert” macromolecules in crowded solution should definitely be taken into account to draw a more complete picture of a protein in a crowded milieu. This review shows that in addition to the excluded volume effects important players of the crowded environments are viscosity, perturbed diffusion, direct physical interactions between the crowding agents and proteins, soft interactions, and, most importantly, the effects of crowders on solvent properties.
Highlights
Macromolecular crowding is known to affect protein folding, binding of small molecules, interaction with nucleic acids, enzymatic activity, protein-protein interactions, and protein aggregation
To check the hypothesis that the changes in the solvent properties of aqueous media might be induced by the crowding agents, the solvatochromic comparison method was used to determine the solvent dipolarity/polarizability (π*), hydrogen-bond donor acidity (α), and hydrogen-bond acceptor basicity (β) of aqueous solutions of different polymers (Dextran, PEG, Ficoll, UCON, and PVP) with the polymer concentration up to 40% typically used as crowding agents [159]
It is clear that the excluded volume effect is not the only factor affecting the behavior of various biomolecules in a crowded environment
Summary
Cells are tightly packed with various biological macromolecules (proteins, protein complexes, nucleic acids, ribonucleoproteins, polysaccharides, etc.), suggesting that the intracellular environment is extremely crowded and has rather limited free space. Proteins are not bound covalently to the highly porous silica matrix, and encapsulated macromolecules are unable to escape the glass under most solvent conditions [19], the sol-gel glass matrix does substantially limit the rotational freedom of the protein [22] not limiting the exchange of the solvent that freely permeates the silica matrix Another important advantage of this approach is the optical transparency of the resulting glass products that allows application of the majority of spectroscopic techniques used to monitor the structure of proteins in dilute solutions, such as fluorescence [23,24] and circular dichroism (CD) [19,20]. All aforementioned encapsulation techniques provide suitable conditions for studying the effects of molecular confinement on different aspect of protein structure and dynamics and on the solvent dynamics and properties, the use of solutions with high concentrations of inert polymers represents the most common approach to model the various effects of macromolecular crowding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
