We use frequency-domain fluorometry to determine the anisotropy decays of the tryptophan emission from S. nuclease and from the model compound gly-trp-gly. Resolution of the rapid and complex anisotropy decays was enhanced by global analysis of the data measured in the presence of quenching by either oxygen or acrylamide. Data were obtained at four to six quencher concentrations, and the data analyzed globally to recover the anisotropy decay. Because the decay times were decreased by quenching, measurements were possible to a upper frequency limit of 2 GHz. The anisotropy decay of gly-trp-gly revealed 40 ps of the indole ring, which was resolved from the overall 150 ps correlation times of the tripeptide. The anisotropy decay of nuclease displayed a 90 /ps component as well as a 10 ns component due to overall rotational diffusion. We believe these highly resolved anisotropy decays are suitably for comparison with molecular dynamic simulations.
|Number of pages||8|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|State||Published - 24 Jun 1988|
|Event||Time-Resolved Laser Spectroscopy in Biochemistry 1988 - Los Angeles, United States|
Duration: 11 Jan 1988 → 17 Jan 1988