(136a) Enzymatic Activity from a Designed Model Proteome

Enzyme engineering seeks to modify or create proteins with an enhanced ability for catalysis or binding. Protein and enzyme engineering often begin with naturally occurring proteins. However, natural proteins have evolved for specific purposes and are already biased towards particular tasks. Proteins that are designed de novo have the potential to be used in a wider variety of bioengineering applications since they have not evolved for specific functions. In order to probe the potential for enzymatic activity within unselected proteins, we are studying a designed artificial proteome comprised of a combinatorial library of de novo, four-helix bundle proteins. Libraries of genes encoding four-helix bundle proteins were constructed using binary patterning of hydrophobic and hydrophilic residues. By screening sequences that were not designed for any particular function, we determined the likelihood of finding rudimentary activity within the model proteome. Once activity was discovered within the proteome, we implemented directed evolution on selected sequences to improve activity. This approach yielded novel proteins with several types of catalytic activity.