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Picosecond relaxation of the fluorescence probes ANS and TNS in aqueous solutions
Author(s) -
May P.G.,
Sibbett W.,
Taylor J.R.
Publication year - 1981
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(81)80610-2
Subject(s) - section (typography) , library science , computer science , operating system
Fluorescent dyes whose quantum yields are particularly sensitive to their environment have been extensively used as probes in structural studies of biological species [I]. Interpretation of the emission properties is used to give information on structure and relaxation dynamics. Dyes of the N-arylaminonaphthalene sulfonate family have been widely applied as probes of the polarity of sites in proteins or as hydrophobic probes since the fluorescence of these molecules in non-polar solvents varies dramatically from that in polar solvents [2,3]. The fluorescence properties of these organic dyes covalently linked to proteins has been shown to depend upon the conformational state of the protein [4]. Generally, the most common feature of the fluorescence examined is the quantum yield. However, interest now is being directed towards understanding the kinetics of many of the processes in biological specimens following excitation with a short burst of energy. Therefore, time-resolved emission of the fluorescence is essential for an indication of the conformational changes in the specimen following excitation, solvent reorientation, complex formation or energy transfer processes, which straightforward measurement of quantum yield is incapable of providing. To understand these processes, it is first needed to examine the fluorescence decay of the fluorescence probes themselves following excitation. In the past, information of this type has been rather limited. This is due to the fact that many of the probes in aqueous solutions for example have extremely low quantum yields [5 J and ultrafast (-ps) decays, making accurate measurement difficult. However, our recently developed synchroscan streak camera used in conjunction with a low average power CW mode-locked dye laser, enables picosecond lifetimes to be examined routinely with a resolution of -3 ps. Here, we report on the measurement of the decay kinetics of the commonly used fluorescence probes, determining their radiative and non-radiative decay rates and examining these decays in various mixed solvent solutions of variable viscosity and polarity.