Chapter 12, Problem 7CONQ

In Chapter 9, we considered the dimensions of the double helix (see Figure 9.12). In an $\alpha$ helix of a protein, there are 3.6 amino acids per complete turn. Each amino acid advances the $\alpha$

helix by $\text{0}\text{.15 nm;}$

a complete turn of an $\alpha$

helix is $\text{0}\text{.54 nm}$

in length. As shown in Figure 12.6, two α helices of a transcription factor occupy the major groove of the DNA. According to Figure 12.6, estimate the number of amino acids that bind to this region. How many complete turns of the $\alpha$

helices occupy the major groove of DNA?