HOW PROTEINS RECOGNIZE THE TATA BOX

The crystal structure of a complex of human TATA-binding protein with TATA-sequence DNA has been solved, complementing earlier TBP/DNA analy ses from Saccharomyces cerevisiae and Arabidopsis thaliana. Special in sight into TATA box specificity is provided by considering the TBP/DNA complex, not as a protein molecule with bound DNA, but as a DNA duple x with a particularly large minor groove ligand. This point of view pr ovides explanations for: (1) why T-A base-pairs are required rather th an C-G; (2) why an alternation of T and A bases is needed; (3) how TBP recognizes the upstream and downstream ends of the TATA box in order to bind properly; and (4) why the second half of the TATA box can be m ore variable than the first. (C) 1996 Academic Press Limited