TY - JOUR
T1 - Complex homogeneous and heterogeneous fluorescence anisotropy decays
T2 - Enhancing analysis accuracy
AU - Bajzer, Željko
AU - Moncrieffe, Martin C.C.
AU - Penzar, Ivo
AU - Prendergast, Franklyn G.
N1 - Funding Information:
This work was supported by NIH Grant GM 34847 and the Mayo Foundation.
PY - 2001
Y1 - 2001
N2 - In biological macromolecules, fluorophores often exhibit multiple depolarizing motions that require multiple lifetimes and rotational relaxation times to define fluorescence intensity and anisotropy decays. The related analysis of time-correlated single-photon counting data becomes uncertain due to the multitude of decay parameters and numerical sensitivity to deconvolution of the instrument response function (IRF) via discretization of integrals. By using simulations we show that improved discretizations based on quadratic and cubic local approximations of the IRF yield more accurate estimation of short rotational relaxation times and lifetimes than the commonly used Grinvald-Steinberg discretization, which in turn appears more reliable than two discretizations based on linear local approximations of the IRF. In addition, our simulation suggests that cubic approximation is the most advantageous in discriminating complex heterogeneous and homogeneous anisotropy decay. We show that among three different information criteria, the Akaike information criterion is best suited for detection of heterogeneity in rotational relaxation times. It is capable of detecting heterogeneity even when anisotropy decay appears homogeneous within statistical errors of estimation.
AB - In biological macromolecules, fluorophores often exhibit multiple depolarizing motions that require multiple lifetimes and rotational relaxation times to define fluorescence intensity and anisotropy decays. The related analysis of time-correlated single-photon counting data becomes uncertain due to the multitude of decay parameters and numerical sensitivity to deconvolution of the instrument response function (IRF) via discretization of integrals. By using simulations we show that improved discretizations based on quadratic and cubic local approximations of the IRF yield more accurate estimation of short rotational relaxation times and lifetimes than the commonly used Grinvald-Steinberg discretization, which in turn appears more reliable than two discretizations based on linear local approximations of the IRF. In addition, our simulation suggests that cubic approximation is the most advantageous in discriminating complex heterogeneous and homogeneous anisotropy decay. We show that among three different information criteria, the Akaike information criterion is best suited for detection of heterogeneity in rotational relaxation times. It is capable of detecting heterogeneity even when anisotropy decay appears homogeneous within statistical errors of estimation.
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U2 - 10.1016/S0006-3495(01)75827-4
DO - 10.1016/S0006-3495(01)75827-4
M3 - Article
C2 - 11509386
AN - SCOPUS:0034866087
SN - 0006-3495
VL - 81
SP - 1765
EP - 1775
JO - Biophysical Journal
JF - Biophysical Journal
IS - 3
ER -