Funds are requested for the purchase of a stand-alone molecular modeling system to be shared by nine scientists for investigating a range of problems in macromolecular structure. The molecular systems to be investigated include proteins, nucleic acids, polysaccharides and lipids. For all of these, the modeling studies are coupled to experimental investigations that use a variety of spectroscopic and biochemical methods. In addition to serving as a research tool, the system will be used for the development of new modeling software for very large nucleic acids and for lipids. It will also serve as the principal resource for a graduate course in molecular modeling.