Forster resonance energy transfer studies

The Forster resonance energy transfer can be used as a spectroscopic ruler in the range of 10-100 A. The distance between the donor and acceptor molecules should be constant during the donor lifetime, and greater than about 10 A in order to avoid the effect of short-range interactions. The validity of such a spectroscopic ruler has been confirmed by studies on model systems in which the donor and acceptor are separated by well-defined rigid spacers. Several precautions must be taken to ensure correct use of the spectroscopic ruler, which is based on the use of Eqs (9.1) to (9.3) ... 

While the complementary technique Forster resonant energy transfer (FRET), which is widely used for studying distances in proteins requires two different, relatively large chromophores, which must be chosen according to the expected distance, EPR distance measurements can be performed using two identical much smaller nitroxide labels and are precise over a broad range of distances [51,65,66]. 

Fluorescence (or Forster) Resonance Energy transfer (FRET) has been used in many different contexts from mechanism of action to structural studies. These include the mechanism of action of DNA hairpin folding, 523,524 quadruplex folding and unfolding, and the transition of quadruplex to duplex. FRET is also often used to study the mechanism of nucleic acid bending ... 

Finally, studies of the Forster resonance energy transfer between 6-carboxyfluorescein (6-CF) and rhodamine B-labeled melamine formaldehyde particles covered by PAH/PSS multilayers showed that 6-CF interacts with PAH when the outer polyelectrolyte layer is PAH [96] upon increasing the 6-CF concentration, an increase of the fluorescence intensity is observed only above a critical concentration, assumed to correspond to the saturation of the charged groups of PAH by the anionic 6-CF. This phenomenon has been used to titrate the number of amino sites of PAH not interacting with PSS in the polyelectrolyte multilayer film it has been estimated as 1.6/nm. ... 

QDs have been linked to phthalocyanines for Forster resonance energy transfer (FRET) [119-123] and for switch on sensing studies [124—126]. Figure 32 shows a linked nickel tetra amino conjugate (CdTe-QDs-(5-NiTAPc) conjugate for electrochemical studies. 

The elucidation of the structure, dynamics and self assembly of biopolymers has been the subject of many experimental, theoretical and computational studies over the last several decades. [1, 2] More recently, powerful singlemolecule (SM) techniques have emerged which make it possible to explore those questions with an unprecedented level of detail. [3-55] SM fluorescence resonance energy transfer (FRET), [56-60] in particular, has been established as a unique probe of conformational structure and dynamics. [26-55] In those SM-FRET experiments, one measures the efficiency of energy transfer between a donor dye molecule and an acceptor dye molecule, which label specific sites of a macromolecule. The rate constant for FRET from donor to acceptor is assumed to be given by the Forster theory, namely [59,61-64]... 

Forster s theory [1], has enabled the efficiency of EET to be predicted and analyzed. The significance of Forster s formulation is evinced by the numerous and diverse areas of study that have been impacted by his paper. This predictive theory was turned on its head by Stryer and Haugland [17], who showed that distances in the range of 2-50 nm between molecular tags in a protein could be measured by a spectroscopic ruler known as fluorescence resonance energy transfer (FRET). Similar kinds of experiments have been employed to analyze the structure and dynamics of interfaces in blends of polymers. 

Rao M, Mayor S. Use of Forster s resonance energy transfer microscopy to study lipid rafts. Biochim. Biophys. Acta 2005 1746 221-233. 

The Forster-type resonance energy transfer (FRET) has become a common practice in the study of macromolecular structures, conformational changes, in vitro and cellular complex formation, and so on [15]. Ullman introduced its use for clinical diagnostics as a way to make homogeneous immunoassays [16]. 

In 1948 Forster proposed a theory for the resonance energy transfer. He postulated that the rate of transfer depends on the inverse sixth power of the distance between the donor and the acceptor. This predicted distance dependence was verified later by experimental studies of fluorescent donor-acceptor pairs separated by a known distance in defined systems. 

More convincing proof for a particle-enhanced energy transfer mechanism comes from a study of the concentration dependence of the transfer. Bulk Forster transfer leads to a linear dependence on acceptor concentration with constant donor-to-acceptor ratio. The resonance mechanism would be expected to saturate at (relatively) high concentrations and fall off linearly at very low concentrations. 

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