Thursday, November 5, 2009: 9:40 AM
Hereford (Camino Real Hotel)
The cellular milieu is rich in diversity of both simple and complex molecules and is also quite crowded. By contrast, typical sample concentrations employed for in vitro investigations in biophysics and structural biology make use of purified macromolecules in simple buffer systems at concentrations that range from micromolar to millimolar. Although this reductionist approach has proven to be compatible with a wide range of biological and structural studies, it is quite different from the relatively crowded conditions typically found within cells. The importance of these crowding effects for proteins has been recognized for some time, but methods for quantitatively evaluating such effects have been very limited. Furthermore, the influence of crowding on the physical behavior of nucleic acid oligomers remains relatively unexplored. Encapsulation with surfactant-based reverse micelles has emerged as an effective biophysical tool, allowing study of the influence of ionic strength, pH, hydration, and crowding on biologically active macromolecules over a wide range of conditions. Specifically, proteins and nucleic acid oligomers encapsulated within reverse micelles can be studied to determine the effects of confinement and excluded volume. Data from encapsulation studies provide an important bridge between commonly employed dilute in vitro studies and studies of the effects of a crowding environment, as is found in vivo.