9418053 Bloomfield DNA functions in crowded, strongly interacting solutions. The equilibrium and dynamic aspects of its behavior are strongly influenced by its environment. When the volume occupancy of a solution reaches several tens of percent, as it does within cells, simple extrapolations from dilute solution behavior become totally inadequate. Experimental and theoretical approaches will be applied to study the ways in which high polymer concentrations influence the diffusion of DNA, and of proteins which bind to DNA. Fluorescence photo bleaching recovery will be used as a major experimental technique, and modern polymer theoretical concepts and computer simulation as theoretical tools. %%% The goal in this project is to develop a solid experimental and theoretical understanding of the ways in which high polymer concentrations influence the diffusion of DNA, and of proteins which bind to DNA. This should shed light on some important questions in cell biology, such as the segregation of plasmids during cell division in microorganisms, and the location by binding proteins of their specific binding sites in a background of nonspecific DNA. ***
