AKTAxpress FPLC System for Protein Purification 1) Project Summary/Abstract Protein purification capabilities underlie structural biology, protein design, and all aspects of protein science. High-throughput automated protein purification can greatly enhance research productivity when many samples must be handled and multi-step purification protocols optimized. Three leading protein research laboratories at Caltech (Arnold, Rees, Tirrell) are requesting support to purchase an AKTAxpress FPLC (Fast Protein Liquid Chromatography) system. This instrument is capable of performing fully- automated, multi-step purifications in an unattended fashion, resulting in highest possible purity and high yields for applications such as crystallography and biochemical protein characterization. The modular setup allows different purification protocols to be run simultaneously on different modules, enabling the three research groups to purify their proteins without interfering with each other. This instrument will remove a very significant bottleneck to our research efforts: protein purification. Time on current purification systems is fully booked, and requires significant researcher input that will be minimized with the AKTAxpress. The modular setup also allows expansion of capabilities when needed (with addition of new purification 'modules', for a total of up to 12). This instrument will support research into the structural basis of cytochrome P450 function and engineering new P450s for synthesis of human metabolites and drug lead diversification (Arnold), membrane protein crystallographic structure analysis (Rees), and engineering proteins through incorporation of nonnatural amino acids (Tirrell). Cytochrome P450 enzymes are key players in human drug metabolism, and understanding their function is critical to development of safe, effective therapeutics. These enzymes can be used to synthesize authentic metabolites for clinical testing (e.g. for toxicity or enhanced therapeutic function). Integral membrane proteins are targets of most popularly prescribed drugs, yet their structural analysis is still in its infancy. Protein engineering via incorporation of nonnatural amino acids offers exciting new opportunities for protein-based therapeutics and diagnostics as well as new research tools. PUBLIC HEALTH RELEVANCE: The research supported by this instrumentation grant will lead to a better understanding of drug metabolism, drug-drug interactions, and mechanisms of drug action. Protein purification is a fundamental tool in structural biology, protein design, and all aspects of protein science. Protein purification is currently a bottleneck for all three groups requesting this instrumentation, and their research productivity will be significantly enhanced by the requested protein purification system.