Campus Units

Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

10-1991

Journal or Book Title

Journal of Physical Chemistry

Volume

95

Issue

22

First Page

8663

Last Page

8670

DOI

10.1021/j100175a046

Abstract

7-Azaindole is the chromophoric side chain of the nonnatural amino acid 7-azatryptopha11, which we have shown can be incorporated into bacterial protein and is amenable to peptide synthesis. Timeresolved fluorescence measurements of 7-amindole are performed as a function of solvent, pH, and temperature in order to characterize its behavior and to establish criteria for the interpretation of its photophysics when it is incorporated into, or interacts with, proteins. The first time-resolved measurements of 7-azaindole in water are presented. The dependence of the fluorescence properties of 7-azaindole in water with respect to that in various solvents of differing polarity and the temperature dependence of the fluorescence lifetimes of 7-azaindole in H20 and D20, and in CHBOH and CH30D, suggest that the fuorescent species of 7-azaindole in water is a tautomerized excited-state solutesolvent complex. Time-resolved fluorescence measurements as a function of temperature verify the existence in methanol of a ground-state precursor to the 7-azaindole *tautomer” species. Upon optical excitation, this precursor decays into the tautomer in less than 30 ps. Our results are used to rationalize the sensitivity of the fluorescence lifetime of a synthetic peptide containing 7-azatryptophan alone in aqueous solution and in complex with a protein.

Comments

Reprinted (adapted) wit permission from Journal of Physical Chemistry 95 (1991): 8663, doi: 10.1021/j100175a046. Copyright 1991 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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