Use of DLS/Raman to study the thermal unfolding process of lysozyme
The combination of dynamic light scattering (DLS) and Raman spectroscopy has the ability to extract a wealth of chemical, structural, and physical parameters from aqueous protein suspensions. By merging both techniques into one instrument, protein secondary and tertiary structure, along with size changes, can be determined simultaneously from a single experiment on a single small volume sample. Because of its ability to monitor protein structural changes and size changes concurrently, this interleaved technique is particularly useful when studying protein unfolding, as during an unfolding process, the secondary and tertiary structure of a protein change, along with the size.
Here we demonstrate the viability of using a combined DLS/Raman instrument for study of the lysozyme unfolding process as a result of thermal stress. Thermal jump and ramp experiments are performed on lysozyme solutions at pH 4. Raman and DLS results indicate that any protein structural and size changes that occur as the result of increased temperature (up to 80°C) are reversible.