HOPS: A Distributed Hybrid Optimization Technique for Protein Structure Prediction Alberto Maria Segre Department of Management Sciences Department of Computer Science Program in Applied Mathematical and Computational Sciences The University of Iowa Iowa City, IA (USA) The key to understanding the mechanism of life lies in understanding how proteins work. Nearly all functional aspects of an organism rely on proteins; enzymes, brain chemicals like dopamine, hormones, and hundreds of thousands of others. Surprisingly, a properly working protein works because it has just the right three dimensional shape, a shape determined by its molecular composition, which is described in the genomic code. Given that we now have access to extensive genomic information, the next challenge for computational biologists is to determine a protein's three dimensional shape -- and, consequently, its biological function -- from its primary structure, expressed as the sequence of constituent amino acids. We have been working on a new hybrid optimization approach to this problem that builds on previous work in distributed search techniques for mechanized reasoning and combinatorial optimization, various continuous optimization methods, and protein energetics. In this talk, I will describe the general architecture of our system, give an update on our recent progress, and demonstrate some preliminary folding results. Joint work with Yinyu Ye (Management Sciences/Applied Mathematics), Kenneth Murphy (Biochemistry), Mauro Leoncini (CNR, Pisa, Italy), and Giovanni Resta (CNR, Pisa, Italy).