THz absorption spectroscopy of solvated β-lactoglobulin

Abstract

The influence of β-lactoglobulin (βLG) on the fast sub-picosecond collective hydration dynamics in the solvent was investigated by THz absorption spectroscopy as a function of pH. It is well-known that a change in pH from pH 6 to pH 8 reversibly opens or closes the binding cavity by a transition of the E-F loop. Furthermore, the aggregation of the protein into dimers is affected, which is thought to be triggered by changes in the enzyme's electrostatic potential. Our data reveal that pH has a clear influence on the THz absorption of βLG. We discuss this influence in light of the changes observed in the sub-psec solute/solvent dynamics when probed by THz spectroscopy, which are, in turn, seen to correlate with changes in the pH value.

Tuning the local solvent composition at a drug carrier surface: the effect of dimethyl sulfoxide/water mixture on the photofunctional properties of hypericin–β-lactoglobulin complexes

“…Furthermore, mapping of the highly populated binding sites for organic probes is valuable to identify 'hot spots' for the binding of small molecules. [30][31][32][33] The distribution of DMSO molecules on the protein surface is consistent with the observation, based on THz spectroscopy, that bLG is a relatively hydrophobic protein not displaying an extended long-range hydration dynamics, 34 as is observed for other hydrophilic proteins. 35,36 Hence, these results suggest that DMSO might stabilize the attachment of monomeric Hyp to the clefts located at the interface of 2bLG.…”

Solvent dynamics play a decisive role in the complex formation of biologically relevant redox proteins

“…the hydration shell, have a distinct absorption which differs from bulk water, consistent with previous studies of proteins in solution. 18,36,37,39 However, the manner in which water interacts with the two proteins is different, evidenced by the opposite behavior in a avg . Coupling of water to the protein depends upon its surface properties, in which the local topography influences interactions with water.…”

“…previous measurements of other proteins. [34][35][36][37] If the decrease in absorption is occurring solely due to a lowered water concentration, a linear decrease at every measured frequency as a function of protein concentration would be observed.…”

Methanol–Water-Dependent Structural Changes of Regenerated Silk Fibroin Probed Using Terahertz Spectroscopy

“…[34][35][36] However, the absorption spectra for complex protein are always featureless and changes monotonically with frequency. [37][38][39][40] The THz spectra analysis for large proteins is hampered by the absence of distinct spectral features.…”