Structure Of Proteins

amino acids, while the two  chains each contain 146 amino acids. Its hydrophobic side chains point inwards to the centre of the molecule, and its hydrophilic side chains face outwards, making it soluble in water. A mutation which causes one of the hydrophilic amino acids to be replaced by a hydrophobic amino acid, thereby reducing its solubility, is responsible for the disease sickle cell anaemia.

The protein coats of some viruses such as the tobacco mosaic virus, are composed of many polypeptide chains arranged in a highly ordered fashion.