Helix-Turn-Helix

The image shows a helix-turn-helix DNA-binding motif bound to DNA.

Examine the relationship of the two helices, the interaction of helix 1 with the major groove of the DNA, and the interaction of helix 2 with the sugar-phosphate backbone of the DNA.

A specialized form of the helix-turn-helix motif called a homeodomain can also be displayed.