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Proceedings Paper

Mag-indo-1 as a potential reporter of the 3D conformation of protein subdomains
Author(s): Pierre M. Viallet; Tuan Vo-Dinh; Terry Bunde; Anne-Cecile Ribou; Jean Vigo; Jean-Marie Salmon
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Paper Abstract

Mag-indo-1 is a well known fluorescent probe. Magnesium complexation results in a shift of the emission fluorescence spectrum from 480 nm to 417 nm with an intensity proportional to the magnesium concentration in the range 0.6 to 30 mM. Although designed as a specific magnesium chelator, Mag-indo-1 is also able to bind calcium and zinc. All these cationic interactions induced the same spectral shift but the fluorescence intensity and the dissociation constant are dependent of the nature of the cation. Furthermore Mag-indo-1 can also bind proteins through a specific interaction with some histidin residues. That interaction induces a characteristic spectral shift of the emission fluorescence spectra from 480 to 457 nM. All these properties suggest that Mag-indo-1 could be used to study the protein-cation binding. Emission and synchronous fluorescence techniques have been used to monitor that interaction with proteins such as bovine serum albumin, human serum albumin, turkey white egg lysozyme. Using a method of resolution of complex fluorescence spectra, it has been possible to calculate the number of interaction sites and the correlative dissociation constants. Depending on the nature of the protein a quenching of the natural fluorescence of the protein was observed, associated with an energy transfer from some tryptophan(s) to Mag-indo-1. All these data were tentatively correlated with the available information on the 3D conformation of the proteins. These results suggest that Mag-indo-1 could be used as an intramolecular fluorescent ruler to monitor the changes in 3D conformation of specific sub-domains of proteins.

Paper Details

Date Published: 1 May 1998
PDF: 12 pages
Proc. SPIE 3253, Biomedical Sensing and Imaging Technologies, (1 May 1998); doi: 10.1117/12.308035
Show Author Affiliations
Pierre M. Viallet, Univ. de Perpignan (France)
Tuan Vo-Dinh, Oak Ridge National Lab. (United States)
Terry Bunde, Oak Ridge National Lab. (United States)
Anne-Cecile Ribou, Univ. de Perpignan (France)
Jean Vigo, Univ. de Perpignan (France)
Jean-Marie Salmon, Univ. de Perpignan (France)

Published in SPIE Proceedings Vol. 3253:
Biomedical Sensing and Imaging Technologies
Robert A. Lieberman; Tuan Vo-Dinh, Editor(s)

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