Figure 2 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
The gene organization of lux operon region in bioluminescence bacteria of Photobacterium species. Photobacterium leiognathi ATCC 25,521 (Pl), Photobacterium leiognathi 741 (Pl), Photobacterium phosphoreum NCMB 844 (Pp). Arrow indicates the direction of transcription. 'r' represent for riboflavin and the functions of genes are shown in Figure 1.
Source publication
Lumazine protein is a member of the riboflavin synthase superfamily and the intense fluorescence is caused by non-covalently bound to 6,7-dimethyl 8-ribityllumazine. The pRFN4 plasmid, which contains the riboflavin synthesis genes from Bacillus subtilis, was originally designed for overproduction of the fluorescent ligand of 6,7-dimethyl 8-ribityll...
Context in source publication
Context 1
... genes coding for the enzymes and proteins responsible for the light-emitting reaction in the bioluminescent bacteria exist in a cluster forming an operon [4]. The genes related to riboflavin (vitamin B 2 ) biosynthesis on the downstream of the lux operon of Photobacterium species were reported [5][6][7] (Figure 2). The biosynthesis of riboflavin is essential in the bioluminescent bacteria, as it is a precursor of FMNH 2 (riboflavin 5 -phosphate), which is the substrate of the bioluminescence reaction as shown in Figure 1. ...
Citations
... In a series of studies regarding the generation of fluorescent bacteria, we initially started to work with pRFN4 plasmids by inserting the lumazine protein gene from P. leiognathi to test fluorescence intensities and single-cell imaging [10]. By binding one molecule of lumazine to the protein, the fluorescence intensity of N-LumP is increased because of its lumazine chromophore [12]. ...
... Proteins are as follows: lumazine protein (LuxL), α and β subunits of luciferase (LuxAB), fatty acid reductase complex (LuxCDE), non-fluorescent flavoprotein (LuxF), flavin reductase (LuxG), GTP cyclohydrolaseII (RibA), dihydroxy-butanone 4-phosphate synthase (RibB), lumazine synthase (RibH), and riboflavin synthase (RibE). Modified from reference[10]. ...
Lumazine protein from marine luminescent bacteria of Photobacterium species bind with very high affinity to the fluorescent chromophore 6,7-dimethyl-8-ribitylumazine. The light emission of bacterial luminescent systems is used as a sensitive, rapid, and safe assay for an ever-increasing number of biological systems. Plasmid pRFN4, containing the genes encoding riboflavin from the rib operon of Bacillus subtilis, was designed for the overproduction of lumazine. To construct fluorescent bacteria for use as microbial sensors, novel recombinant plasmids (pRFN4-Pp N-lumP and pRFN4-Pp luxLP N-lumP) were constructed by amplifying the DNA encoding the N-lumP gene (luxL) from P. phosphoreum and the promoter region (luxLP) present upstream of the lux operon of the gene by PCR and ligating into the pRFN4-Pp N-lumP plasmid. A new recombinant plasmid, pRFN4-Pp luxLP-N-lumP, was constructed with the expectation that the fluorescence intensity would be further increased when transformed into Escherichia coli. When this plasmid was transformed into E. coli 43R, the fluorescence intensity of transformants was 500 times greater than that of E. coli alone. As a result, the recombinant plasmid in which the gene encoding N-LumP and DNA containing the lux promoter exhibited expression that was so high as to show fluorescence in single E. coli cells. The fluorescent bacterial systems developed in the present study using lux and riboflavin genes can be utilized in the future as biosensors with high sensitivity and rapid analysis times.
