Collapse of the hydration shell of a protein prior to thermal unfolding

Abstract

Based on high statistical quality wide-angle X-ray scattering data for the unfolding-refolding process of hen egg-white lysozyme (HEWL), we have analysed the change of the hydration shell as a function temperature using the program CRYSOL. The present results suggest that the decrease of the hydration-shell density starts from a lower temperature than the transition temperature of the collapse of the tertiary structure of HEWL. Although the use of CRYSOL for scattering data for proteins before the transition has an apparent limitation, the collapse of the hydration shell prior to the unfolding of HEWL agrees with a slight tendency of the radius of gyration to decrease during the thermal unfolding process.

The physics of pulling polyproteins: a review of single molecule force spectroscopy using the AFM to study protein unfolding

“…Water forms a hydration layer around proteins which is dynamic and exchanges with bulk water due to thermal fluctuations on the surface of the protein [45,[45][46][47][48][49][50]. The structure of the protein can be maintained by this hydration layer [51] and conformational changes are influenced by hydration dynamics [52]. The hydrogen bonding network within the water must therefore be dynamic and flexible to facilitate structural changes associated with the function of the protein [53].…”

Effect of cold stress on physicochemical characteristics and biological activity of equine chorionic gonadotropin

“…Protein denaturation involves a change in the protein structure (generally an unfolding) with the subsequent loss of activity. Heat denaturation and loss of biological activity have been linked to the breakup of the 2-Dspanning water network around protein molecules, due to increasing hydrogen bond breakage with higher temperatures (Koizumi et al, 2007). As shown in Fig.…”

Increased stability in plasma and enhanced cellular uptake of thermally denatured albumin-coated liposomes

“…The primary structure of BSA makes it more flexible and hydrophobic [28,29]. Though hydrophobic character of primary structure of protein can induce its aggregation, the protein aggregation, is inhibited by newly formed hydrogen bonds with surrounding protein chains [29,30]. These indicate that the surface of thermally denatured liposomes is changed to be hydrophilic by hydrogen bonding with water molecules.…”

“…The primary structure of BSA induced by unfolding of BSA could form new hydrogen bonds between water molecules and amide nitrogens or carbonyl oxygens of the amide bond in aqueous solution [18][19][20]. The primary structure of BSA makes it more flexible and hydrophobic [28,29]. Though hydrophobic character of primary structure of protein can induce its aggregation, the protein aggregation, is inhibited by newly formed hydrogen bonds with surrounding protein chains [29,30].…”