Time-resolved fluorescence polarization from ordered biological assemblies.
We calculate the time dependence of the polarized fluorescence signal from fluorescent-labeled elements of a biological assembly that are rotationally diffusing in an arbitrary three-dimensional angular potential. We have formulated this calculation using the model-independent description of the angular potential wherein the angular potential is described by an expansion in a complete set of orthonormal functions with the expansion coefficients (or order parameters) determined by time-independent methods (Burghardt, T. P., 1984, Biopolymers, 23:2382-2406). We have applied the calculation to fluorescent-labeled myosin cross-bridges in relaxed muscle fibers. In a related paper we describe the experimental observation of the myosin cross-bridges rotationally diffusing in an angular potential (Burghardt, T. P., and N. L. Thompson, 1985, Biochemistry, 24:3731-3735).
D000818:Animals; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D009126:Muscle Relaxation; D009132:Muscles / Q000502:physiology*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors