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Proceedings Paper

Site-to-site diffusion in proteins as observed by energy transfer and frequency-domain fluorometry
Author(s): Joseph R. Lakowicz; Ignacy Gryczynski; Jozef Kusba; Wieslaw M. Wiczk; Henryk Szmacinski; Michael L. Johnson
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Paper Abstract

We report measurements of site-to-site diffusion in proteins, using frequency-domain measurements of time-dependent energy transfer. The possibility of such measurements is shown from simulations which demonstrate that donor-to-acceptor (D-to-A) diffusion alters the donor frequency response, and that this effect is observable in the presence of a distribution of distances. For decay times typical of tryptophan fluorescence, the simulations indicate D-to-A diffusion coefficients can be measured ranging from 10-7 to 10-5 cm2/s. This possibility was verified by studies of a methylene-chain linked D-A pairs in solutions of varying viscosity. D-to-A diffusion was also measured for acceptor-labeled melittin in the random coil and (alpha) -helical states. Unfolding of troponin I results in increased D-A diffusion. Surprisingly, more rapid diffusion was observed for melittin in the (alpha) -helical state, but over a limited range of distances.

Paper Details

Date Published: 1 April 1992
PDF: 16 pages
Proc. SPIE 1640, Time-Resolved Laser Spectroscopy in Biochemistry III, (1 April 1992); doi: 10.1117/12.58215
Show Author Affiliations
Joseph R. Lakowicz, Univ. of Maryland School of Medicine (United States)
Ignacy Gryczynski, Univ. of Maryland School of Medicine (United States)
Jozef Kusba, Univ. of Maryland School of Medicine (United States)
Wieslaw M. Wiczk, Univ. of Maryland School of Medicine (United States)
Henryk Szmacinski, Univ. of Maryland School of Medicine (United States)
Michael L. Johnson, Univ. of Virginia School of Medicine (United States)


Published in SPIE Proceedings Vol. 1640:
Time-Resolved Laser Spectroscopy in Biochemistry III
Joseph R. Lakowicz, Editor(s)

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