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Proceedings Paper

Transient effects in the solute quenching of tryptophan residues in proteins
Author(s): Maurice R. Eftink
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Paper Abstract

Fluorescence quenching reactions, using such quenchers as oxygen and acrylamide, have been used to obtain information about the kinetic exposure of tryptophan residues in proteins. Often, both dynamic and static quenching components can be observed. The transient term of the Smoluchowski equation has been shown by Lakowicz et al (J. Biol. Chem. 10907-10910 (1987)) to be needed to fit acrylamide and oxygen quenching lifetime data with proteins. Here we show that this transient term can also explain the apparent static quenching that can be observed in some cases. By numerical integration of an impulse-response function, which includes a transient solute quenching term, we have simultaneously fitted intensity and phase lifetime Stern-Volmer plots for the oxygen and acrylamide quenching of selected single tryptophan proteins. These fits require a single fitting parameter, the diffusion of the quencher. Using this fitting procedure we have reinvestigated the effect of bulk viscosity on the acrylamide quenching of the fluorescence of the buried tryptophan in ribonuclease T1. We show that for this protein the intensity and lifetime data sets can be better fitted by a two-step diffusion model.

Paper Details

Date Published: 1 May 1990
PDF: 9 pages
Proc. SPIE 1204, Time-Resolved Laser Spectroscopy in Biochemistry II, (1 May 1990); doi: 10.1117/12.17705
Show Author Affiliations
Maurice R. Eftink, Univ. of Mississippi (United States)

Published in SPIE Proceedings Vol. 1204:
Time-Resolved Laser Spectroscopy in Biochemistry II
Joseph R. Lakowicz, Editor(s)

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