ANISOTROPY DECAYS of SINGLE TRYPTOPHAN PROTEINS MEASURED by GHz FREQUENCY-DOMAIN FLUOROMETRY with COLLISIONAL QUENCHING

Joseph R. Lakowicz, Ignacy Gryczynski, Henryk Szmacinski, Henryk Cherek, Nanda Joshi

Research output: Contribution to journalConference articlepeer-review

Abstract

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.

Original languageEnglish
Pages (from-to)178-185
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume909
DOIs
StatePublished - 24 Jun 1988
EventTime-Resolved Laser Spectroscopy in Biochemistry 1988 - Los Angeles, United States
Duration: 11 Jan 198817 Jan 1988

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