Ligand fluorescence

Fluorescence energy transfer. Panel (a) shows the fluorescence characteristics of a hypothetical protein A (excitation and emission maxima at 290 nm and 350 nm, respectively). In (b). Ligand B fluoresces with an emission maximum at 450 nm when excited at 350 nm. Panel (c) shows that the formation of the protein-ligand complex can be monitored using an excitation wavelength of 290 nm and recording the decrease in protein fluorescence at 350 nm or the increase in ligand fluorescence at 450 nm... 

Figure 11.20 The ligand fluorescence arising from the sensitiser is much broader than the lanthanide-based lines (reproduced by permission of The Royal Society of Chemistry).

To further extend the utility of CPMV virions as tools in nanobiotechnology, it was shown that CPMV particles can be utilized as building blocks for the construction of monolayer, bilayer, and multilayer arrays on surfaces in a controlled manner [109]. CPMV virions were labeled with two different ligands fluorescent dyes that enabled differential detection, and biotin molecules that allowed the... 

Water-soluble cyclophane 86145 exhibited a well-defined fluorescence band at 290 nm with a 210 nm excitation. The emission intensity was markedly increased by complexation with Zn2+ which forms a 2 1 (metal-ligand) complex. The fluorescence emission is pH-independent to pH 2. The fluorescence enhancement factor is 5.0 at pH 6 and 50 at pH 8.6 (due to the pH dependence of the free ligand). Ni2+ and Cu2+ ions quenched the ligand fluorescence via a PET mechanism. Furthermore, when cyclophane 86 was coordinated to Cu2+, the molar absorptivity of the transition band observed at 260 nm was increased by a factor of about 10. Such a large spectral change was not observed for the Zn2+ and Ni2+ complexes. In the Cu2+ complex, the two phenyl rings of the cyclophane are expected to be... 

Burd, J.F., Carrico, R.J., Fetter, M.C., Buckler, R.T., Johnson, R.D., Bo-guslaski, R.C. and Christner, J.E. (1977). Specific protein-binding reactions monitored by enzymatic hydrolysis of ligand-fluorescent dye conjugates. Anal. Biochem. 77, 56-57. 

Copper(ll) complexes of a glutamic acid derived diamido-diamino ligands 12 (Fig. 5c) containing anthracene units were also used as enantioselective sensors for a-hydroxy acids (in particular mandelate) and amino acids [68]. The ligand fluorescence was quenched by copper(ll) and recovered by addition of the analytes. A mechanism involving photoinduced electron transfer (PET) was proposed, and the conditional stability constants of the ternary complexes was found to be different for the two mandelate enantiomers (with KiJK = 15.2) in this study. 

Chen Z-H, He Y-B, Hu C-G et al (2008) Preparation of a metal-ligand fluorescent chemosensor and enantioselective recognition of carboxylate anions in aqueous solution. Tetrahedron Asymmetry 19 2051-2057... 

Weber, G., Daniel, E. Cooperative effects in binding by bovine serum albumin. II. The binding of l-anilino-8-naphthalenesulfonate. Polarization of the ligand fluorescence and quenching of protein fluorescence. Biochemistry 5, 1900-1907 (1966)... 

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