Proteins are the basis of how biology gets things done. As enzymes , they are the driving force behind all of the biochemical reactions which makes biology work. As antibodies , they recognize invading elements and allow the immune system to get rid of the unwanted invaders.
Genes are the functional units of the genome .
Each gene encodes the information for how to make a specific protein. What we don't understand is how and why many different protein sequences , each encoded by a different gene, can form the same three-dimensional protein structure . The number of different genes, each encoding a specific protein sequence, is thousands of times greater than the number of different three-dimensional protein structures. Protein sequence design seeks to understand this mystery by designing as many sequences as possible that could form the same structure. Because there are twenty different amino acids, and proteins contain dozens to hundreds of amino acids, the number of possible protein sequences is astronomically large.