Terbium luminescence-lifetime heterogeneity and protein equilibrium conformational dynamics.

R. H. Austin, D. L. Stein, J. Wang

    Research output: Contribution to journalArticlepeer-review


    The fluorescence decay of the rare earth terbium when bound to the protein calmodulin changes from a simple exponential decay to a complex nonexponential decay as the temperature is lowered below 200 K. We have fit the observed decay curves by assuming that the terbium emission is a forced electric dipole transition and proteins have a distribution of continuous conformational states. Quantitative fits to the data indicate that the root-mean-square configurational deviation of the atoms surrounding the terbium ion is 0.2 A, in good agreement with other measurements. We further point out that because the protein seems to undergo a glass transition yet retains configurational order at room temperature, the proper name for the physical state of a protein at room temperature is the rubber-like state.

    Original languageEnglish (US)
    Pages (from-to)1541-1545
    Number of pages5
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number6
    StatePublished - Mar 1987

    ASJC Scopus subject areas

    • General


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