Abstract
I will discuss our protein design based-efforts to rationally modify the properties of existing proteins and to create novel proteins from first principals. The results of these studies greatly contribute to our understanding of the structure and activity of natural proteins. Moreover, they allow us to create novel proteins with hitherto unseen properties. Specific examples that I will discuss include modification of the stability of biomedically important proteins, design and selection strategies to investigate and change protein-protein interactions and the design of novel protein-based catalysts.