Analytical ultracentrifugation studies on the self-association of yeast TBP

In eukaryotes, there is a universal requirement for the TA 1 A binding pio tent, TBP, in transcriptional initiation. Although its roles in tranrriptiouaJ initiation are becoming well-defined, very little is known about the physicochemical basis of TBP interactions with other macromolecules. As a first step in this direction, we have started to characterize the self-association reactions of TBP. Sedimentation equilibrium studies reveal that yeast TBP is involved in a monomer to tetrarner association. The effects of KCI. and temperature on the monomer lo tetramer association constant will be presented. Shape information on the TBP oligonter, obtained from analysis of sedimentation velocity experiments, will also be presented.