The information content or complexity of an homologous protein family

Functionally equivalent amino acids

The specificity of proteins is determined, not only by the amino acid sequence, but also by the active pocket of amino acids that contains metal ions such as iron, zinc, copper and manganese (Thompson and Orvig, 2003). Thyroxine, which contains iodine, is the major hormone secreted by the thyroid gland. Thyroid gland deficiency disease is very common, especially in women.

Some substitutions of amino acids at certain sites may have a destabilizing effect on the protein-folding pathways. Thus, the selectivity of amino acids is determined by the primary role played in the protein folding process as well as by the requirements of the activity of the completed and folded molecule (Hoang et al., 2002). Proteins that misfold can form extracellular or intracellular aggregates, resulting in disastrous cellular dysfunction. Human protein-folding disorders include Alzheimer's and Parkinson's diseases (Selkoe, 2003).

The sequence hypothesis of Watson and Crick and Shannon's information theory

We now are able to address the application of Shannon's information theory to the sequence hypothesis of Watson and Crick. Usually in the olive groves of academe, suggestions from other departments are not received gladly. Nevertheless, Gamow's proposal that the sequence hypothesis could bring biology over into the group of the exact sciences could not be ignored.