Project Summary A Chirascan V100 circular dichroism (CD) spectrometer is requested for the University of Missouri. CD is a widely applicable biochemical method for probing the secondary- and tertiary structures of proteins and nucleic acids in solution. It is also useful for evaluating macromolecular stability, monitoring the effects of various perturbants (pH, temperature, etc.) and can be used to study ligand-binding events. Data obtained from the proposed instrument will benefit the entire life sciences community on our campus, including the 6 major and 5 minor NIH-funded users on this proposal. In particular, research programs in structural biology and virology will be heavy users of this instrument. The Chirascan V100 will provide a state-of-the-art instrument with new features and accessories that are otherwise unavailable on campus. Among its advantages are superior sensitivity and accuracy, automatic calibration, an inexpensive air-cooled illumination source, and low nitrogen consumption. The Chirascan V100 is easy to use, compact, and requires minimal consumables. We request the following accessories to meet the needs of our user community: sample titrator with pH meter; fluorometer and fluorescence anisotropy detector; and a multi-cell sample turret. Justification for each of these is detailed in the proposal. The requested instrument will replace a non-functional, >25 year old Aviv spectrometer owned by the Biochemistry Department, which was the only shared CD on campus. Although painstakingly maintained for many years, this instrument was retired in 2018, due to an accumulation of problems that are beyond repair. The Chirascan V100 will be housed and administered in the Molecular Interactions research core facility in the centrally located Life Sciences Center. Instrument operation, supervision, and user training will be conducted by the Assistant Director of the core, a highly qualified research scientist. Detailed information on a financial plan, institutional commitment, and an external advisory committee for the instrument is provided. The Chirascan V100 will maximize recent campus investments in structural biology, and greatly benefit the overall growth and development of the life sciences community on our campus.