PROJECT SUMMARY/ABSTRACT Investigators at the University of Iowa have a growing need to analyze macromolecular interactions and conformational dynamics at a single-molecule level. For over a decade, University of Iowa Carver College of Medicine Protein and Crystallography (P&C) Facility has been providing the University of Iowa investigators access to and help in operating of basic and state-of-the-art instrumentation for biophysical and structural analysis of proteins and nucleic acids. Addition of an instrument that will allow researchers to visualize and study biologically important molecules individually, in real time, and under physiological conditions will significantly enhance research programs at the University of Iowa. It will provide a much- needed tool for developing mechanistic understanding of how cells work and communicate, how molecular machines assemble and function. While several groups at the University of Iowa have built systems for single-molecule analysis in their labs, none of these instruments allows for simultaneous visualization and manipulation of biological macromolecules. Currently, there is also no single-molecule instruments centrally available to non-expert users at the University of Iowa. This proposal requests funds for a LUMICKS C-Trap(R) instrument, the first and only commercial instrument for single-molecule analysis of macromolecular interactions that combines high resolution optical tweezers, fluorescence microscopy and microfluidics, and therefore allows simultaneous manipulation and visualization of the macromolecular complexes. It is an important tool for the single- molecule multiparameter analysis of macromolecular interactions, assembly and function of molecular machines and conformational dynamics of proteins and nucleic acids. The C-Trap(R) will be housed at the P&C Facility whose personnel will be responsible for the instrument maintenance, user training, and will assist the investigators with experimental design, instrument operation and data analysis. The C-Trap(R) instrument will have an immediate impact on numerous NIH- funded research projects at the University of Iowa and collaborators, and will also serve as an important resource for our collaborators in regional institutions. The projects that will immediately benefit from this instrument include studies of the molecular processes that ensure genome stability, assembly and dynamics of multicomponent molecular machines, viral genome folding, chromatin organization, as well as enzymes that represent attractive targets for development of new anticancer, anti-neurodegeneration, anti-viral and antimicrobial therapies.