Lumazine protein

Two types of fluorescent proteins have been isolated from luminous bacteria and studied in detail. The first of them are the blue fluorescent lumazine proteins (LumPs) containing lumazine as their chromophores, which were isolated from P. phosphoreum and P. fischeri (Gast and Lee, 1978 Koda and Lee, 1979 O Kane et al.y 1985). The second are the yellow fluorescent proteins (YFPs) containing a chromophore of FMN or riboflavin, isolated from P. fischeri strain Y-l (Daubner et al., 1987 Macheroux et ai, 1987 ... 

Fig. 2.4 The spectrum of bacterial luminescence measured with B. harveyi luciferase, FMN, tetradecanal and NADH, in 50 mM phosphate buffer, pH 7.0, at 0°C (dashed line from Matheson et al., 1981) and the absorption and fluorescence emission spectra of LumP (solid lines) and Rf-LumP (dotted lines) obtained from P. leiog-natbi, in 25 mM phosphate buffer, pH 7.0, containing 1 mM EDTA and 10 mM 2-mercaptoethanol, at room temperature (from Petushkov et al, 2000, with permission from Elsevier). LumP is a lumazine protein, and Rf-LumP contains riboflavin instead of lumazine in the lumazine protein. Fluorescence emission curves are at the right side of the absorption curves.

Lee, J. (1990). Lumazine protein and the bioluminescence of Photobacterium. In Curtius, H.-C., et al. (eds.), Chem. Biol. Pteridines, Proc. Int. Symp. Pteridines Folic Acid Deriv., 9th, 1989, pp. 445-456. de Gruyter, Berlin. 

Lee, J. (1993). Lumazine protein and the excitation mechanism in bacterial bioluminescence. Biophys. Chem. 48 149-158. 

Lee, J., O Kane, D. J., and Gibson, B. G. (1989). Bioluminescence spectral and fluorescence dynamics study of the interaction of lumazine protein with the intermediates of bacterial luciferase bioluminescence. Biochemistry 28 4263-4271. 

O Kane, D. J., Karle, V. A., and Lee, J. (1985). Purification of lumazine proteins from Photobacterium leiognathi and Photobacterium... 

Small, E. D., Koda, P., and Lee, J. (1980). Lumazine protein from the bio-luminescent bacterium Photobacterium phosphoreum. Purification and characterization./. Biol. Chem. 255 8804—8810. 

Lumazine proteins (LumPs), 44, 45 Lumbricidae, 234 Luminodesmus photoprotein,... 

In this study, we examined the effect of the O2 concentration on BL with varying hydrogen ion (H concentrations and cell density. Moreover, the effect of O2 on the BL of Photobacterium phosphoreum, carrying the lumazine protein responsible for the blue-shifted BL, was also examined. 

The change in the intensity of the blue-shifted BL of P. phosphoreum (Fig. 3) may be ascribed to the change in apportionment of the respiratory reducing power to the luciferases reaction. Furthermore, it seems that the highly fluorescent property of lumazine protein is hardly influenced by the redox state of the respiratory components unlike YFP. That is, the cellular redox state may not be influential in the electronic excitation transfer interaction responsible for the blue-shifted BL. 

Lee J. Sensitization by lumazine proteins of the bioluminescence emission ft om the reaction of bacterial luciferases. Photochem Photobiol 1982 36 689-97. 

Paralogues of eubacterial riboflavin synthase (designated as lumazine protein, yellow fluorescent protein, and blue fluorescent protein) without enzymatic activity have been isolated from several luminescent bacteria. These proteins are highly fluorescent and are believed to modulate to serve as optical transponders that modulate the spectral characteristics of bacterial bioluminescence.Energy is believed to be transferred from activated bacterial luciferase to the fluorescent proteins by radiation-less transfer. 

Figure 23 Structural superposition of lumazine protein (green, PDB entry code 3DDY ) and riboflavin synthase from Schizosaccharomycespombe (yellow, PDB entry code 1KZC ). The C-terminal segment of riboflavin synthase is marked by red color.

Certain proteins have been known to function as secondary emitters, affecting the wavelength and efficiency of the light emission. For example, a yellow fluorescent protein (YFP) of a V. fischeri strain accepts excitation energy from a lucifer-ase-bound intermediate and emits yellow light (23). In contrast, the lumazine protein (21 kDa), a fluorescent protein from Photobacterium phosphoreum (24), causes an apparent blue shift of the light produced by the luciferase reaction. The absorption maximum shifts from 496 to 475 nm in the presence of the lumazine protein. 

Lee, J., Wang, Y., and Gibson, B.G., Electronic excitation transfer in the complex of lumazine protein with bacterial bioluminescence intermediates. Biochemistry, 30, 6825, 1991. 

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