Biopolym. Cell. 2001; 17(3):221-224.
http://dx.doi.org/10.7124/bc.0005AE
Structure and Function of Biopolymers
On the interpretation of decay-associated fluorescence spectra in proteins
1Ladokhin A. S.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680
  2. Department of Physiology and Biophysics University of California
    Irvine, CA 92697-4560, USA

Abstract

Calculating decay-associated spectra (DAS) is a common mode of analyzing complex fluorescence decay in proteins. Unfortunately, these spectra are attributed almost exclusively to certain species in the population of macromolecules (retainers), often without sufficient evidence. An alternative explanation of decay heterogeneity, based on structural relaxation., was believed to require a negative DAS component. Here we demonstrate that dipolar relaxation of the indole molecule, lacking any rotameric forms, doesn't always result in negative pre-exponential amplitude. We conclude that the shape of DAS alone is not sufficient to differentiate among various causes of heterogeneity of tryptophan fluorescence decay in proteins.
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