This article reports a free-solution, label-free method for quantitative characterization of macromolecular interactions using dynamic light scattering, a temperature-controlled plate reader, and a multi-well concentration gradient. This nondestructive technique enabled determination of stoichiometry of binding, equilibrium dissociation constant, and thermodynamic parameters, as well as the impact of temperature, buffer salinity, and a small-molecule inhibitor. The low volume capability of dynamic light scattering reduced the required sample to 426 pmol/experiment, with detection limits for 150 kDa proteins anticipated to be in the low femtomole range.
Hanlon, A. D.; Larkin, M. I.; Reddick, R. M. Biophysical Journal 2010, 98, 297-304. DOI: 10.1016/j.bpj.2009.09.061