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Impact of site-directed mutant luciferase on quantitative green and orange/red emission intensities in firefly bioluminescence.

Wang Y, Akiyama H, Terakado K, Nakatsu T - Sci Rep (2013)

Bottom Line: While the mutation caused different emission spectra, the spectra differed only in the intensity of the green component (λmax ~ 560 nm).In contrast, the orange (λmax ~ 610 nm) and red (λmax ~ 650 nm) components present in all the spectra were almost unaffected by the modifications to the luciferases and changes in pH.Our results reveal that the intensity of the green component is the unique factor that is influenced by the luciferase structure and other reaction conditions.

View Article: PubMed Central - PubMed

Affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 2778584, Japan. wang@issp.u-tokyo.ac.jp

ABSTRACT
Firefly bioluminescence has attracted great interest because of its high quantum yield and intriguing modifiable colours. Modifications to the structure of the enzyme luciferase can change the emission colour of firefly bioluminescence, and the mechanism of the colour change has been intensively studied by biochemists, structural biologists, optical physicists, and quantum-chemistry theorists. Here, we report on the quantitative spectra of firefly bioluminescence catalysed by wild-type and four site-directed mutant luciferases. While the mutation caused different emission spectra, the spectra differed only in the intensity of the green component (λmax ~ 560 nm). In contrast, the orange (λmax ~ 610 nm) and red (λmax ~ 650 nm) components present in all the spectra were almost unaffected by the modifications to the luciferases and changes in pH. Our results reveal that the intensity of the green component is the unique factor that is influenced by the luciferase structure and other reaction conditions.

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Related in: MedlinePlus

Green (~560 nm) Gaussian components in the spectra of wild-type and Y257F/A/E mutant Lcr luciferases at pH 8.0.
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f3: Green (~560 nm) Gaussian components in the spectra of wild-type and Y257F/A/E mutant Lcr luciferases at pH 8.0.

Mentions: The spectra of the WT and the four mutant Lcr luciferases showed three patterns of pH sensitivity: the intensities and peak wavelengths of the WT Lcr and Y257F spectra were very sensitive to the change in pH, and their spectra included the green component whose intensity was sensitive to pH; those of the Y257A spectra were less sensitive to pH, and the spectra had a weak green component; in contrast, those of the Y257E and Y257R spectra were insensitive to pH, and the green components were negligible or absent from their spectra. Therefore, we conclude that the intensity of the green Gaussian component dominantly determines the shape and peak wavelength of the spectrum and thus regulates the pH sensitivity of the spectrum and quantum yield. To further illustrate this feature, in Fig. 3, we picked out the green Gaussian components (~560 nm) in the spectra of the WT and Y257F/A/E mutant luciferases at pH 8.0. This figure clearly shows that the substitution for the amino acid residue at position 257 principally modifies the emission intensity of the green Gaussian component and thus regulates the pH sensitivity of the bioluminescent spectra. Only the intensity of the green component was sensitive to pH changes. Since the green component was present in the spectra of the Y257F mutant and WT luciferase, their spectra were pH dependent. However, the green component was absent in the spectra of Y257E and Y257R, and hence their spectra and quantum yields were insensitive to pH.


Impact of site-directed mutant luciferase on quantitative green and orange/red emission intensities in firefly bioluminescence.

Wang Y, Akiyama H, Terakado K, Nakatsu T - Sci Rep (2013)

Green (~560 nm) Gaussian components in the spectra of wild-type and Y257F/A/E mutant Lcr luciferases at pH 8.0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750616&req=5

f3: Green (~560 nm) Gaussian components in the spectra of wild-type and Y257F/A/E mutant Lcr luciferases at pH 8.0.
Mentions: The spectra of the WT and the four mutant Lcr luciferases showed three patterns of pH sensitivity: the intensities and peak wavelengths of the WT Lcr and Y257F spectra were very sensitive to the change in pH, and their spectra included the green component whose intensity was sensitive to pH; those of the Y257A spectra were less sensitive to pH, and the spectra had a weak green component; in contrast, those of the Y257E and Y257R spectra were insensitive to pH, and the green components were negligible or absent from their spectra. Therefore, we conclude that the intensity of the green Gaussian component dominantly determines the shape and peak wavelength of the spectrum and thus regulates the pH sensitivity of the spectrum and quantum yield. To further illustrate this feature, in Fig. 3, we picked out the green Gaussian components (~560 nm) in the spectra of the WT and Y257F/A/E mutant luciferases at pH 8.0. This figure clearly shows that the substitution for the amino acid residue at position 257 principally modifies the emission intensity of the green Gaussian component and thus regulates the pH sensitivity of the bioluminescent spectra. Only the intensity of the green component was sensitive to pH changes. Since the green component was present in the spectra of the Y257F mutant and WT luciferase, their spectra were pH dependent. However, the green component was absent in the spectra of Y257E and Y257R, and hence their spectra and quantum yields were insensitive to pH.

Bottom Line: While the mutation caused different emission spectra, the spectra differed only in the intensity of the green component (λmax ~ 560 nm).In contrast, the orange (λmax ~ 610 nm) and red (λmax ~ 650 nm) components present in all the spectra were almost unaffected by the modifications to the luciferases and changes in pH.Our results reveal that the intensity of the green component is the unique factor that is influenced by the luciferase structure and other reaction conditions.

View Article: PubMed Central - PubMed

Affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 2778584, Japan. wang@issp.u-tokyo.ac.jp

ABSTRACT
Firefly bioluminescence has attracted great interest because of its high quantum yield and intriguing modifiable colours. Modifications to the structure of the enzyme luciferase can change the emission colour of firefly bioluminescence, and the mechanism of the colour change has been intensively studied by biochemists, structural biologists, optical physicists, and quantum-chemistry theorists. Here, we report on the quantitative spectra of firefly bioluminescence catalysed by wild-type and four site-directed mutant luciferases. While the mutation caused different emission spectra, the spectra differed only in the intensity of the green component (λmax ~ 560 nm). In contrast, the orange (λmax ~ 610 nm) and red (λmax ~ 650 nm) components present in all the spectra were almost unaffected by the modifications to the luciferases and changes in pH. Our results reveal that the intensity of the green component is the unique factor that is influenced by the luciferase structure and other reaction conditions.

Show MeSH
Related in: MedlinePlus