A new technique has recently been developed which extends the time resolution of measurements of circular dichroism (CD) from the millisecond time regime which standard techniques can resolve to the nanosecond time regime. It is proposed that this technique be refined so that CD measurements can be made with even better time resolution and with more sensitivity. An effective technique for measuring CD signals with good time resolution would be an important tool for biophysics since it would be a link between structural studies and kinetic studies. Since biological processes clearly depend on structural properties of biological molecules and are dynamic in nature, this linkage has great potential utility. It is thus the goal of this research to make the transient CD technique a useful tool. To do this studies will be made to increase the capabilities of the technique and to test the limitations of the technique. With this information it will be possible to determine for what types of biophysical studies the technique would be valuable. In the process of characterizing the transient CD technique, three applications will initially be studied. First, the CD spectrum of the triplet state of Ru(bpy)+2,3 will be measured. This system will provide a good test of a multi-channel detection scheme for measuring transient CD spectra. In addition myoglobin and hemoglobin transient CD spectra and kinetics will be studied. These systems will be useful in extending the time resolution and sensitivity of the transient CD technique. Finally, the transient CD spectra of rhodopsin photolysis intermediates will be determined.
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