Abstract
A dynamic light scattering (DLS) experiment is quick and nondestructive, and it requires a minimum of purified material (typically <1 mg). Macromolecular samples can be assayed routinely for monodispersity as a function of solvent conditions; the presence of ligands, inhibitors, or cofactors; or following posttranslational modifications or partial proteolysis. A DLS experiment can be used as the screening step in a crystallization strategy that involves the use of protein engineering to generate a number of related recombinant constructs of a macromolecule or macromolecular complex. This approach may also find some application in the challenging arena of membrane-protein crystallization, where it could be used to screen different recombinant constructs and monitor various detergent solubilization strategies. Sample monodispersity is also critical for other biophysical methods, including nuclear magnetic resonance spectroscopy and small-angle X-ray and neutron scattering. DLS is a useful screening step for the samples prepared for these solution-based techniques; it represents an important method for quality control during the manufacture of recombinant proteins for therapeutic use.