DNA SEQUENCE-SPECIFIC RECOGNITION BY THE SACCHAROMYCES-CEREVISIAE TATA-BINDING PROTEIN - PROMOTER-DEPENDENT DIFFERENCES IN THE THERMODYNAMICS AND KINETICS OF BINDING

The equilibrium binding and association kinetics of the Saccharomyces cerevisiae TATA Binding Protein (TBP) to the E4 and Major Late promote rs of adenovirus (TATATATA and TATAAAAG, respectively), have been dire ctly compared by quantitative DNase I titration and quench-flow ''foot printing''. The equilibrium binding of TBP to both promoters is descri bed by the equilibrium TBP + DNA(''TATA'') <-> TBP-DNA(''TATA''). The salt dependence of TBP binding to both promoters is identical within e xperimental error while the temperature dependence differs significant ly. The observed rate of association follows simple second-order kinet ics over the TBP concentration ranges investigated. The salt and tempe rature dependencies of the second-order association rate constants for TBP binding the two promoters reflect the dependencies determined by equilibrium binding. The TBP-E4 promoter interaction is entropically d riven at low temperature and enthalpically driven at high temperature while the TBP-Major Late promoter reaction is entropically driven over virtually the entire temperature range investigated. These data sugge st that the reaction mechanisms of TBP-promoter interactions are TATA sequence-specific and provide for differential regulation of promoters as a function of environmental variables.