Refolding of urea-induced denaturation of model proteins by trimethylamine N-oxide

• Published in: Thermochimica acta Vol. 526; no. 1; pp. 143 - 150
• Main Authors: Attri, Pankaj, Venkatesu, Pannuru
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 10.11.2011; Elsevier
• Subjects: Biological and medical sciences; Conformational dynamics in molecular biology; Cyclic dipeptides; denaturation; dipeptides; Dynamic light scattering; energy; Fundamental and applied biological sciences. Psychology; hydrodynamics; light scattering; Molecular biophysics; proteins; Refolding; Transfer free energy; trimethylamine; Trimethylamine-N-oxide; Urea; Transfer free energy; Cyclic dipeptides; Urea; Dynamic light scattering; Refolding; Trimethylamine-N-oxide; Cyclic peptides; Light scattering; Denaturation; Conformational changes; Free energy; Protein; Dipeptides; Models; Amine oxide; Thermodynamic properties; Energy transfer
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2011.09.006

► We have studied the refolding of urea-induced denaturation of CDs by TMAO. ► We have performed Δ G′ tr and the hydrodynamic diameter ( d H ) of CDs. ► We observed positive values of Δ G′ tr for CDs from water to TMAO. ► The negative Δ G′ tr contributions were obtained for CDs from water to urea. ► Our results show that TMAO stabilize while urea destabilizes the CDs. ► Our results show that TMAO is a refolding additive for CDs. The biomolecules are known to be stabilized by osmolytes, trimethylamine-N-oxide (TMAO) while urea, destabilizes the protein structures. The deleterious effect of urea on proteins has been counteracted by TMAO is well understood; nonetheless, refolding of urea-induced conformational changes of proteins by TMAO is still an active subject. To understand the refolding ability of TMAO from urea-induced denaturation of biomolecules, we have performed transfer free energy (Δ G′ tr) and the hydrodynamic diameter ( d H ) of cyclic dipeptides (CDs) such as, cyclo(Gly–Gly), and cyclo(Leu–Ala) through solubilities and dynamic light scattering (DLS) measurements, respectively. We observed positive and negative values of Δ G′ tr for CDs from water to TMAO and urea, respectively. Our results reveal that TMAO is a refolding additive for urea deleterious actions on CDs at 1:1 and 1:2 molar ratios of TMAO and urea. However, TMAO (1 M) fails to refolding CDs structure from the urea (3–5 M)-induced conformational changes on CDs.