Taurine as a water structure breaker and protein stabilizer

Abstract

The enhancing effect on the water structure has been confirmed for most of the osmolytes exhibiting both stabilizing and destabilizing properties in regard to proteins. The presented work concerns osmolytes, which should be classified as “structure breaking” solutes: taurine and N,N,N-trimethyltaurine (TMT). Here, we combine FTIR spectroscopy, DSC calorimetry and DFT calculations to gain an insight into the interactions between osmolytes and two proteins: lysozyme and ubiquitin. Despite high structural similarity, both osmolytes exert different influence on protein stability: taurine is a stabilizer, TMT is a denaturant. We show also that taurine amino group interacts directly with the side chains of proteins, whereas TMT does not interact with proteins at all. Although two solutes weaken on average the structure of the surrounding water, their hydration spheres are different. Taurine is surrounded by two populations of water molecules: bonded with weak H-bonds around sulfonate group, and strongly bonded around amino group. The strong hydrogen-bonded network of water molecules around the amino group of taurine further improves properties of enhanced protein hydration sphere and stabilizes the native protein form. Direct interactions of this group with surface side chains provide a proper orientation of taurine and prevents the group from negative influence. The weakened hydration sphere of TMT breaks up the hydrogen-bonded network of water around the protein and destabilizes it. However, TMT at low concentration stabilize both proteins to a small extent. This effect can be attributed to an actual osmophobic effect which is overcome if the concentration increases.Electronic supplementary materialThe online version of this article (doi:10.1007/s00726-017-2499-x) contains supplementary material, which is available to authorized users.

Taurine suppresses liquid-liquid phase separation of lysozyme protein

“…Some compounds compete with hydrophobic groups for available water molecules, thereby altering hydrophobic bonding. In the folded protein, the hydrophobic contribution is probably the most important stabilizing factor in proteins (Yancey 2005; Bruździak et al 2018). The contribution of hydrophobic bonding has been demonstrated for the regulation of temperature-induced protein unfolding, urea denaturation and protein regeneration.…”

“…Taurine is a beta-amino acid found in high concentration (typically 1∼40 mmol/kg tissue weight) in mammalian tissues (Chesney 1985; Ito et al 2008; Jentsch 2016)v. Taurine functions as a compatible organic osmolyte, which regulates intracellular ionic balance, thereby maintaining cell volume (Schaffer et al 2000, 2010). Compatible osmolytes also contribute to the thermodynamic stability of proteins by minimizing the water-protein interaction (Bruździak et al 2018). The role of compatible osmolytes in LLPS formation of proteins has been evaluated by Cinar et al, who demonstrated that trimethylamine oxide (TMAO), which is an organic osmolyte of marine fish, enhances LLPS formation of gamma-crystallin(Cinar et al 2019).…”

Neurochemical alterations of different cerebral regions in rats with myocardial ischemia-reperfusion injury based on proton nuclear magnetic spectroscopy analysis

“…Taurine is present in different brain regions and demonstrates an important inhibitory amino acid associated with extensive neuroprotective activities within the body [ 29 , 41 ]. It has a functional role in osmoregulation in the brain under pathological conditions [ 38 , 42 , 43 ]. Jakaria et al reported that taurine has potential therapeutic effects against different neurological disorders and protects against injuries and toxicities of the nervous system [ 39 ].…”

“…Compared to the control group, the rats in the IR group displayed a dramatic increase in the level of taurine in many brain regions including the PC, OC, TC, STR, HP, and THA, as well as a decrease in choline in the MID and MED-PONs but an increase in choline in the THA. It is well-known that taurine and creatine are neuroprotective metabolites [38][39][40]. Taurine is present in different brain regions and demonstrates an important inhibitory amino acid associated with extensive neuroprotective activities within the body [29,41].…”

Expedition into Taurine Biology: Structural Insights and Therapeutic Perspective of Taurine in Neurodegenerative Diseases

“…Capable of establishing water-mediated interactions, taurine gives stability to proteins against stress conditions capable of causing protein denaturation [191][192][193][194][195]. NMR (Nuclear magnetic resonance spectroscopy) studies revealed the involvement of taurine in the refolding of denatured proteins [196], while spectroscopic and calorimetric studies revealed its role in increasing the thermal stability of lysozyme [197,198]. Khan et al revealed the role of taurine in counteracting the denaturing of proteins by urea, via increasing the stability of the protein for the maintenance of its function [199].…”