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PHYSICS AND ASTRONOMY Science at the Edge Friday, May 21, 2010 11:30a 1400 Biomedical & Physical Sciences Bldg Refreshments at 11:15a in 1400 BPS Bldg Jose Onuchic University of California at San Diego "sharing the energy landscape for folding and function: from small proteins to molecular motors" Globally the energy landscape of a folding protein resembles a partially rough funnel with reduced energetic frustration. A consequence of minimizing energetic frustration is that the topology of the native fold also plays a major role in the folding mechanism. Some folding motifs are easier to design than other suggesting the possibility that evolution not only selected sequences with sufficiently small energetic frustration but also selected more easily designable native structures. The overall structure of the on-route and off-route (traps) intermediates for the folding of more complex proteins is also strongly influenced by topology. Many cellular functions rely on interactions among proteins and between proteins and nucleic acids. The limited success of binding predictions may suggest that the physical and chemical principles of protein binding have to be revisited to correctly capture the essence of protein recognition. Going beyond folding, the power of reduced models to study the physics of protein assembly will be discussed. Since energetic frustration is sufficiently small, native topology-based models, which correspond to perfectly unfrustrated energy landscapes, have shown that binding mechanisms are robust and governed primarily by the protein's native topology. These models impressively captured many of the binding characteristics found in experiments and highlighted the fundamental role of flexibility in binding. Deciphering and quantifying the key ingredients for biological self-assembly is invaluable to reading out genomic sequences and understanding cellular interaction networks. Going even beyond binding and recognition, we will be discussing the energy landscape for the molecular motor kinesin. ***To make an appointment to meet with the speaker, contact Prof. Lisa Lapidus ( <mailto:[log in to unmask]> [log in to unmask])*** Kim Crosslan Undergraduate Secretary, Dept. Physics & Astronomy Michigan State University 1312 Biomedical & Physical Sciences East Lansing, MI 48824 517-884-5531 <mailto:[log in to unmask]> [log in to unmask]