Site-to-site diffusion in proteins as observed by energy transfer and frequency-domain fluorometry

Joseph R. Lakowicz, Ignacy Gryczynski, Jozef Kusba, Wieslaw M. Wiczk, Henryk Szmacinski, Michael L. Johnson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

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 α-helical states. Unfolding of troponin I results in increased D-A diffusion. Surprisingly, more rapid diffusion was observed for melittin in the α-helical state, but over a limited range of distances.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherPubl by Int Soc for Optical Engineering
Pages196-211
Number of pages16
ISBN (Print)0819407860
StatePublished - 1992
EventTime-Resolved Laser Spectroscopy in Biochemistry III - Los Angeles, CA, USA
Duration: 20 Jan 199222 Jan 1992

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1640
ISSN (Print)0277-786X

Other

OtherTime-Resolved Laser Spectroscopy in Biochemistry III
CityLos Angeles, CA, USA
Period20/01/9222/01/92

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    Lakowicz, J. R., Gryczynski, I., Kusba, J., Wiczk, W. M., Szmacinski, H., & Johnson, M. L. (1992). Site-to-site diffusion in proteins as observed by energy transfer and frequency-domain fluorometry. In Proceedings of SPIE - The International Society for Optical Engineering (pp. 196-211). (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 1640). Publ by Int Soc for Optical Engineering.