Distribution of distances in native and denatured troponin i, from frequency-domain measurements of fluorescence energy transfer

Herbert C. Cheung, Chien Kao Wang, Ignacy Gryczynski, Michael L. Johnson, Joseph R. Lakowicz

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We used time-dependent fluorescence energy transfer to determine the distribution of donor-to-acceptor distances in native and denatured troponin I(TnI). The single tryptophan residue (trp 158) of TnI served as the donor (D), and the acceptor (A) was a labeled cysteine residue (cys 133). The time-dependent intensity decays of the donor were measured by the frequency-domain method. The frequency-response of the donor emission, in the absence and presence of acceptor, was used to recover the distribution of D to Å distances, using an algorithm which accounts for the intrinsic multi-exponential decay of the donor. In the native state the D-A distribution is characterized by an average distance of 23 A and a half-width of 12 Å. Denaturation results in a modest increase in the average distance to 27 A, and a dramatic increase in half-width to 47 Å. We believe the ability to recover distance distributions will have numerous applications in the characterization of biological macromolecules.

Original languageEnglish
Pages (from-to)163-169
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume909
DOIs
StatePublished - 24 Jun 1988

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