Share Email Print
cover

Proceedings Paper

A new approach to interpretation of heterogeneity of fluorescence decay in complex biological systems
Author(s): Jakub Wlodarczyk; Borys Kierdaszuk
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Decays of tyrosine fluorescence in protein-ligand complexes are described by a model of continuous distribution of fluorescence lifetimes. Resulted analytical power-like decay function provides good fits to highly complex fluorescence kinetics. Moreover, this is a manifestation of so-called Tsallis q-exponential function, which is suitable for description of the systems with long-range interactions, memory effect, as well as with fluctuations of the characteristic lifetime of fluorescence. The proposed decay functions were applied to analysis of fluorescence decays of tyrosine in a protein, i.e. the enzyme purine nucleoside phosphorylase from E. coli (the product of the deoD gene), free in aqueous solution and in a complex with formycin A (an inhibitor) and orthophosphate (a co-substrate). The power-like function provides new information about enzyme-ligand complex formation based on the physically justified heterogeneity parameter directly related to the lifetime distribution. A measure of the heterogeneity parameter in the enzyme systems is provided by a variance of fluorescence lifetime distribution. The possible number of deactivation channels and excited state mean lifetime can be easily derived without a priori knowledge of the complexity of studied system. Moreover, proposed model is simpler then traditional multi-exponential one, and better describes heterogeneous nature of studied systems.

Paper Details

Date Published: 7 October 2005
PDF: 8 pages
Proc. SPIE 5862, Diagnostic Optical Spectroscopy in Biomedicine III, 58620X (7 October 2005); doi: 10.1117/12.633038
Show Author Affiliations
Jakub Wlodarczyk, Warsaw Univ. (Poland)
Borys Kierdaszuk, Warsaw Univ. (Poland)


Published in SPIE Proceedings Vol. 5862:
Diagnostic Optical Spectroscopy in Biomedicine III
Mary-Ann Mycek, Editor(s)

© SPIE. Terms of Use
Back to Top