So alpha carotene is the type of fibrous protein that is found in our hair and in our nails. Now, alpha carotene consists of these two individual and long fibers. These polypeptide chains as shown in the following diagram. And both of these polypeptide chains essentially are composed of these right handed alpha helixes and these right handed alpha helixes together intertwined to form a left handed coil known as the alpha coiled coil. Now, how exactly are these polypeptide chains? How exactly are these two subunits actually held together?