My group uses de novo design and protein engineering to prepare artificial model proteins that can perform a desired function. The purpose of this effort is twofold: first, by reproducing the main properties and functions of natural proteins in a model system, one can test iteratively hypotheses on the specific contribution of each amino acid to the protein activity; second, once the key principles are elucidated, it will be possible to design novel proteins with activities beyond those of natural proteins. Methods utilized include computational modeling, solid phase synthesis, molecular biology techniques and enzymatic screening.

Current projects in the lab are divided in three main areas:

Artificial metalloproteins for solar to fuel energy conversion

The conversion of solar energy to usable fuel requires the assembly of a specialized chain of reactions, each typically facilitated by a metallic active site. To obtain the necessary spatial organization, we designed a family of peptides that can self assemble into large complexes functionalized with specialized active sites. We are using a variety of artificial amino acid and natural ligands to engineer [Fe4S4] clusters, diiron clusters, and manganese sites in scaffolding peptides. The ultimate goal is to catalyze biomimetic reactions such as water splitting, CO2reduction, and hydrogen production.

Design of membrane proteins

Membrane proteins function as gateways to the cell, and are crucial in a number of processes related to energy transduction and cell signaling. We are interested in learning how to control protein-protein interactions and cofactor binding in the membrane. To that end we have designed a stable, membrane soluble protein that utilizes a metal cofactor, heme, as active site.

Engineering novel glycan-binding proteins

We are using protein engineering and directed protein evolution to design reagents capable of targeting glycans with high affinity and specificity. The ability of attaching sugars to proteins, called glycosylation, is the most ubiquitous post-translational modification in eukaryotic cells. It is known to have a crucial role in many biological processes, including the immune response, inflammation, and the early stages of bacterial and viral infections. Therefore, the development of specific glycan recognition domains has applications both in basic research and in the diagnosis and therapy of diseases. As part of this effort, we have recently discovered the molecular mechanism of action of a potent anti-HIV protein, cyanovirin, paving the way for the design of improved antiviral proteins.

We are members of the EFRC Center for Bio-Inspired Solar Fuel Production (http://solarfuel.clas.asu.edu/ ) and of the Center for Membrane Proteins in Infectious Diseases (MPID, http://cemilinks.asu.edu/mpid/ )