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Proceedings Paper

Comparison of tyrosine and tryptophan decay kinetics in small peptides
Author(s): J B.A. Ross; W R Laws; H R Wyssbrod; M F Lulka; S J Prestrelski; J D Glass; A Buku
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Paper Abstract

The fluorescence intensity decay of many tryptophan and tyrosine analogues and single tryptophan- or tyrosine-containing peptides and proteins exhibits complex kinetic behavior. Many kinetic schemes have been proposed, invoking either ground-state or excited-state interactions, but the multi-exponentional decays have yet to be explained by a comprehensive model. Our approach has been to try to resolve ground-state from excited-state interactions. We have recently demonstrated that the complex fluorescence decay of tyrosine in model compounds and small peptides can be explained by a ground-state model which predicts a single exponential decay for each rotamer about the Ca-0 bond of the aromatic residue.1'2 This model also predicts that the interconversion between rotamers is much slower than the decay of the excited state of the aromatic side chain. Consequently, the weighting of the expo-nential components should correlate with the ground-state rotamer populations, which can be estimated from proton NMR results. To incorporate the ground-state rotamer populations directly into the analysis of the fluorescence decay data, we developed a linked-function analysis3 which restricts the parameter search space; as a result, proposed kinetic mechanisms can be more rigorously tested. The linked-function can be applied either to the analysis of a single decay curve or to a global analysis4 of a set of related decay curves.

Paper Details

Date Published: 24 June 1988
PDF: 2 pages
Proc. SPIE 0909, Time-Resolved Laser Spectroscopy in Biochemistry, (24 June 1988); doi: 10.1117/12.945385
Show Author Affiliations
J B.A. Ross, Mount Sinai School of Medicine (United States)
W R Laws, Mount Sinai School of Medicine (United States)
H R Wyssbrod, Mount Sinai School of Medicine (United States)
M F Lulka, Mount Sinai School of Medicine (United States)
S J Prestrelski, Mount Sinai School of Medicine (United States)
J D Glass, Mount Sinai School of Medicine (United States)
A Buku, Mount Sinai School of Medicine (United States)

Published in SPIE Proceedings Vol. 0909:
Time-Resolved Laser Spectroscopy in Biochemistry
Joseph R. Lakowicz, Editor(s)

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