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Both time-resolved fluorescence

Recent contributions that both time-resolved fluorescence intensity and anisotropy decay studies have made to om understanding of the structure and d3mamics of proteins and nucleic acids are reviewed in (27). [Pg.77]

Product and services of interest include genomics, proteomics, custom research and services, and instruments, accessories, consumables and software. PerkinElmer proprietary technologies include time-resolved fluorescence which is employed in the sensitive Wallac DELFIA system and Wallac LANCE homogeneous assay system, and fluorescence polarization, [FP]2 , a robust fluorescence-based technique for receptor binding assays that is both fast and easy-to-use. [Pg.274]

Zhu L, Stryjweski WJ, Soper SA (2004) Multiplexed fluorescence detection with micro-fabricated devices with both time-resolved and spectral-discrimination capabilities using near-infrared fluorescence. Anal Biochem 330 206-218... [Pg.36]

As outlined in Section 9.2.1, orientational heterogeneity may affect the determination of a distance distribution, especially in the case of static orientation. Time-resolved fluorescence experiments provide an apparent average distance and an apparent distance distribution containing contributions from both distance and orientation (Wu and Brand, 1992). [Pg.256]

Photodiodes occur in many different varieties and are useful in both steady-state and time-resolved fluorescence studies. Photodiodes designed for use in steady-state or on microsecond time-scales are inexpensive and have effective areas up to a few square millimeters, and are capable of efficiently matching to simple focusing optics. However, as the temporal resolution increases so does the cost, and the effective area has to be reduced. For example, APDs with response times in the 50 psec region have effective diameters ofca. 10 /small active area of high-speed devices is currently the primary drawback in fluorescence studies. Also, photodiodes other... [Pg.406]

Permyakov et alS32) have compared the effects of calcium binding upon the steady-state and time-resolved fluorescence of two different species of fish parvalbumin, one with a single tryptophan (whiting) and one with a single tyrosine (pike). The fluorescence decays of both proteins were best fit by double exponentials either in the presence or absence of calcium. We focus here on the tyrosine results from pike parvalbumin. Calcium binding causes a 50% increase in the tyrosine steady-state fluorescence quantum yield and... [Pg.32]

The first decision to be made in designing an experiment to measure the motional properties of membrane lipids concerns the type of probe molecule. Too often, this choice is made from the point of view of convenience or tradition rather than suitability, although there is now a considerable range of suitable fluorophores from which to choose. The second consideration is the type of measurement to be made. The most detailed and complete motional information is obtained from a time-resolved fluorescence anisotropy measurement which is able to separate the structural or orientational aspects from the dynamic aspects of fluorophore motion. Steady-state anisotropy measurements, which are much easier to perform, provide a more limited physical parameter relating to both of these aspects. [Pg.240]

FIGURE 3.12 Time-resolved fluorescence traces measured at the positions (A) and (B) indicated in Fig. 3.11a. Both time-resolved data were fitted by double exponential functions with the time constant of Tj = 0.3 ps and = 28 ps. (From Fujino, T., Fujima, T., and Tahara, T., Appl. Phys. Lett. 87 131105-131107, 2005. Used with permission.)... [Pg.68]

The transient absorption spectrum of DMABN-F4 in acetonitrile, recorded at 1-ps delay shows an absorption band near 360 nm (Fig. 3a). This band can be attributed to the CT state by comparison with that reported for DMABN in acetonitrile at lOOps (Fig. 3b). For the latter, both the LE state decay and CT state risetime were found to be 6 ps in time-resolved fluorescence measurements with a 4-ps time-resolution streak-camera [6]. From various studies, the CT formation time is now well known to be 4-6 ps [1] so that, at 100 ps, only the CT state is present. Fig. 3a shows that, for DMABN-F4, the CT state is populated in less than 1 ps in acetonitrile. We can thus conclude from the present observation that the access to the CT state for DMABN-F4 is significantly faster than for DMABN in acetonitrile. [Pg.325]

To study the excited state one may use transient absorption or time-resolved fluorescence techniques. In both cases, DNA poses many problems. Its steady-state spectra are situated in the near ultraviolet spectral region which is not easily accessible by standard spectroscopic methods. Moreover, DNA and its constituents are characterised by extremely low fluorescence quantum yields (<10 4) which renders fluorescence studies particularly difficult. Based on steady-state measurements, it was estimated that the excited state lifetimes of the monomeric constituents are very short, about a picosecond [1]. Indeed, such an ultrafast deactivation of their excited states may reduce their reactivity something which has been referred to as a "natural protection against photodamage. To what extent the situation is the same for the polymeric DNA molecule is not clear, but longer excited state lifetimes on the nanosecond time scale, possibly of excimer like origin, have been reported [2-4],... [Pg.471]

There is an equilibrium between DNA binding to the two sites. Time-resolved fluorescence spectroscopy of labeled duplex DNA bound to the Klenow fragment shows that 12% occupies the editing, site and 88% the polymerization.42 The presence of mismatches both slows down elongation and increases the occupancy of the editing site 43 Comparison of all the steps for correct and incorrect nucleotide incorporation confirms that the fidelity stems from discrimination in... [Pg.207]

Various mechanisms for the photoinduced geometrical isomerization of 9-styrylanthracenes have been proposed recently [90-93]. From steady-state and time-resolved fluorescence measurements on the parent 9-styrylanth-racenes 68a/69a and their formyl and 4-phenylsulfonyl derivatives (681/691 68j/69j), it has been concluded that the geometrical isomerization is an adiabatic process which occurs both in the excited singlet and triplet states [90]. Thus, for the conversion of the parent cis compound 68a into 69a, 85%... [Pg.172]

Subsequently, fluorescent MIPs for cGMP were fabricated [46 18, 66, 67]. For that, 1,3-diphenyl-6-vinyl-1 //-pyrazolo 3.4-/ quinoline (PAQ) was introduced as the fluorescent indicator to interact with cGMP in a thin-layer fluorescent MIP chemosensor. Both steady-state (Fig. 1) and time-resolved fluorescence spectroscopy were used as two independent analytical techniques for investigation of the chemosensor properties in the presence of cGMP. Steady-state fluorescence spectroscopy is a common technique applied to MIP sensing. Nevertheless, the use of time-resolved fluorescence spectroscopy combined with microscopy was a new approach to MIP sensing. [Pg.191]

Figure 8 shows a pair of typical time-resolved fluorescence decay traces for 100 / M pyrene in supercritical CO2 (Tr = 1.02 pr = 1.17). Note that the ordinate is logarithmic. The upper and lower panels show results for selective observation in the monomer (400 +. 10 nm) and excimer (460 + 10 nm) regions of the pyrene emission spectrum. Several interesting features are apparent from these traces. First, both decay processes are not single exponential. Second, the excimer emission has a significant contribution from a species that "grows in" between 30 - 75 ns this is a result of the excimer taking time to form (i.e., k in Figure 1). Third, the fits between the experimental data and the model shown in Figure 1 are good. Detailed analysis of these decay traces (10,11,21-26) yields the entire ensemble of photophysical kinetic parameters for the pyrene excimer in supercritical C02. Figure 8 shows a pair of typical time-resolved fluorescence decay traces for 100 / M pyrene in supercritical CO2 (Tr = 1.02 pr = 1.17). Note that the ordinate is logarithmic. The upper and lower panels show results for selective observation in the monomer (400 +. 10 nm) and excimer (460 + 10 nm) regions of the pyrene emission spectrum. Several interesting features are apparent from these traces. First, both decay processes are not single exponential. Second, the excimer emission has a significant contribution from a species that "grows in" between 30 - 75 ns this is a result of the excimer taking time to form (i.e., k in Figure 1). Third, the fits between the experimental data and the model shown in Figure 1 are good. Detailed analysis of these decay traces (10,11,21-26) yields the entire ensemble of photophysical kinetic parameters for the pyrene excimer in supercritical C02.
The above described model sequences have been studied both as oligomers [7,8,11-13,19] and as polymers [9,11,20]. An increase in the size of the helix is known to reinforce its stability, as revealed by their melting curves [18] and attested by X-ray diffraction measurements in solution [21]. Therefore, in this chapter we focus on the polymeric duplexes poly(dGdC).poly(dGdC) [= 1000 base-pairs], poly(dAdT).poly(dAdT) [= 200-400 base-pairs] and poly(dA).poly(dT) [= 2000 base-pairs] studied by us. First we discuss the absorption spectra, which reflect the properties of Franck-Condon states, in connection with theoretical studies. Then we turn to fluorescence properties fluorescence intensity decays (hereafter called simply fluorescence decays ), fluorescence anisotropy decays and time-resolved fluorescence spectra. We... [Pg.128]

This simple RNA stemloop serves as an illustration of how both steady-state and time-resolved fluorescence together provide a detailed description of the properties of an RNA (Hall and Williams, 2004). The sequence of the iron response element (IRE) RNA hairpin loop [C6A7G8U9G10C11] is phylogenetically conserved (numbered from our construct). Cytidine 6 and... [Pg.278]

Normally w-amino-a-arylalkanes can adopt a conformation which produces exciplex fluorescence by a process involving C—C-bond rotation which is very fast. Both 3-(4-dimethylaminophenyl)-l-(9-anthracenyl)propane and 3-(4-dimethylaminophenyl)-l-(l-pyrenyl)propane form fluorescent exciplexes, which by means of picosecond time-resolved fluorescence spectroscopy have been shown to take a few nanoseconds to be formed (Migita et al., 1980, 1981). The rate of intramolecular fluorescent exciplex formation has also been shown to be dependent upon the length of the linking chain, the polarity of the solvent (the build up time decreases as solvent polarity is increased)... [Pg.30]


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Time-resolved fluorescence

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