Biological Wonders of Osmolytes: The Need to Know More

Abstract

Nature has selected osmolytes to protect intracellular macromolecules against denaturing stress conditions. These molecules are accumulated in the intracellular environment at considerably high concentrations. In general, osmolytes are known to stabilize proteins. However, under certain conditions, their destabilizing properties have also been pointed out. A careful qualitative and quantitative understanding of the mechanism of action of osmolytes with proteins from native to different stages of aggregation/fibrillation is extremely important in rational drug design. This review highlights the importance of naturally occurring osmolytes in protein folding, stabilization, and prevention of fibrillation/aggregation related diseases among others. Continued efforts are required to get quantitative insights into osmolyte-protein interactions along with experimental evidences for the much claimed preferential exclusion/preferential hydration phenomenon of osmolyte action. Mechanistic insights into the disease associated roles of osmolytes needs special attention.

Role of Promising Secondary Metabolites to Confer Resistance Against Environmental Stresses in Crop Plants: Current Scenario and Future Perspectives

“…Proline is a group of tiny compounds known as osmolytes or osmoprotectants, therefore, as an osmolyte, proline is an important molecule used by various organisms to combat stress ( Judy and Kishore, 2016 ). Proline levels differ from one species to the next, and proline concentration might be 100 times higher in dry conditions than in wet conditions.…”

Cyanobacteria-Derived Proline Increases Stress Tolerance in Arabidopsis thaliana Root Hairs by Suppressing Programmed Cell Death

“…We did not confirm the identity of these additional compounds, but candidates include EPS, phytohormones, ROS-detoxifying exoproteins and phenolics. EPS such as arabinose, glucose, galactose, rhamnose, xylose and ribose have been detected in N. muscorum CM ( Mehta and Vaidya, 1978 ) and carbohydrates are organic osmolytes that protect macromolecule structure against denaturing stress conditions ( Yancey, 2005 ; Judy and Kishore, 2016 ). Microbial-derived phytohormones have been suggested to play an important role in plant survival fitness ( Fahad et al, 2015 ; Egamberdieva et al, 2017 ).…”

Protective Effect of Biological Osmolytes against Heat- and Chaotropic Agent-Induced Denaturation of Bacillus licheniformis ��-Glutamyl Transpeptidase

“…Carbohydrates, methylamines, and amino acids are three major classes of biological osmolytes [5]. These biological substances can be further categorized into (i) osmolytes, such as trim ethylamine N-oxide (TMAO), sarcosine, sorbitol, sucrose and trehalose, that stabilize proteins by raising free energy of both native and denatured states, (ii) osmolytes, such as, glycine, betaine, proline and glycerol, that only moderately enhance the thermodynamic stability of proteins, (iii) denaturing osmolytes, such asurea, and (iv) counteracting osmolytes, such as the mixture of urea and TMAO) [5].…”

“…Carbohydrates, methylamines, and amino acids are three major classes of biological osmolytes [5]. These biological substances can be further categorized into (i) osmolytes, such as trim ethylamine N-oxide (TMAO), sarcosine, sorbitol, sucrose and trehalose, that stabilize proteins by raising free energy of both native and denatured states, (ii) osmolytes, such as, glycine, betaine, proline and glycerol, that only moderately enhance the thermodynamic stability of proteins, (iii) denaturing osmolytes, such asurea, and (iv) counteracting osmolytes, such as the mixture of urea and TMAO) [5]. Over the last decades, an increasing number of studies have broadened the diverse functions of biological osmolytes pertaining to solubility of proteins [6][7][8][9][10], expression enhancement of enzymes [11,12], and protection of living organisms against extreme environmental conditions [13][14][15][16].…”