CRYSTAL-STRUCTURE OF YEAST TATA-BINDING PROTEIN AND MODEL FOR INTERACTION WITH DNA

The C-terminal 179-aa region of yeast (Saccharomyces cerevisiae) TATA- binding protein (TBP), phylogenetically conserved and sufficient for m any functions, formed crystals diffracting to 1.7-angstrom resolution. The structure of the protein, determined by molecular replacement wit h coordinates from Arabidopsis TBP and refined to 2.6 angstrom, differ ed from that in Arabidopsis slightly by an angle of about 12-degrees b etween two structurally nearly identical subdomains, indicative of a d egree of conformational flexibility. A model for TBP-DNA interaction i s proposed with the following important features: the long dimension o f the protein follows the trajectory of the minor groove; two rows of basic residues conserved between the subdomains lie along the edges of the protein in proximity to the DNA phosphates; a band of hydrophobic residues runs down the middle of the groove; and amino acid residues whore mutation alters specificity for the second base of the TATA sequ ence are juxtaposed to that base.