Metal binding and DNA recognition in transcription factor Sp1.

DNA binding domain of Sp1 encompassing three Cys2His2-type Zn-finger motifs is cloned and expressed in E.coli. The Sp1 fragment shows metal-dependent folding and DNA binding. The Zn(II)-induced folding of the three fingers is probably cooperative. Release of one equivalent of Zn decreases but does not abolish DNA binding activity of Sp1.