Question

A binding assay is performed with a DNA - binding protein and a small DNA duplex. When the concentration of the free DNA duplex is 10 nM, 8% of the protein is bound to DNA (this assumes that the total protein concentration is much lower than that of the dup lex). What is the value of K D ?

Answer 1

The value of K_D can be calculated using the equation K_D = [protein][DNA]/[protein-DNA].

Step-by-step explanation:

The value of KD can be calculated using the equation KD = [protein][DNA]/[protein-DNA]. In this case, the concentration of the free DNA duplex is given as 10 nM and 8% of the protein is bound to DNA.

Let's assume the total protein concentration is much lower than the concentration of the DNA duplex. In that case, if 8% of the protein is bound to DNA, then 92% of the protein is free. So, the concentration of the protein-DNA complex is 8% of the total protein concentration and the concentration of the free protein is 92% of the total protein concentration.

Using the given concentration of the free DNA duplex (10 nM) and the concentration of the free protein (92% of the total protein concentration), we can calculate the concentration of the protein-DNA complex. From there, we can calculate the value of KD using the equation KD = [protein][DNA]/[protein-DNA].