Redesigning the DNA-binding specificity of a zinc finger protein: a data base-guided approach.

A peptide corresponding to the three zinc finger domains of the human transcription factor Sp1 has been expressed and found to bind a consensus Sp1 binding site with the sequence 5'-GGGGCGGGG-3'. Examination of the amino acid distributions within a large zinc finger sequence data base and chemical arguments suggested that a particular Arg to Gln sequence change might convert binding specificity to 5'-GGGGCAGGG-3'. Experimental tests of this hypothesis revealed that such a change could be induced only when two other sequence changes, deduced from examination of sequence correlations, were made as well. These results provide the most direct information to date about how zinc finger proteins might recognize adenine-containing binding sites and bear on the existence and nature of any code between zinc finger protein and binding site sequences.