Protein Design: The Choice of de Novo Sequences

Protein design ultimately comes down to choosing amino acid sequences. In contrast to traditional studies of protein folding and function, the choice is not limited to sequences that nature has provided. Advances in molecular biology and synthetic chemistry have made it possible to produce virtually any sequence of amino acids. The number of possible sequences from which to choose is enormous, and even for a small design, one cannot sample all possibilities. For example, for a relatively short sequence of 100 residues composed of the 20 naturally occurring amino acids, there are 20100 possibilities.