Team UALberta's Beetector system relies on the use of visual reporter called amajLime (BBa_K1033916) which has been used in a variety of BioBricks. The characterization of the spectral properties of amajLime is well documented by Hong Kong 2017. However, their characterization lacked information regarding amajLime's relative quantum yield, which is a parameter needed to tune our model for the Beetector's visual signal strength (See Model).
Figure 1:Extracted amajLime under white light (top) and UV light (bottom)
In order to determine this value, our team measured the absorbance and fluorescence data of amajLime and made subsequent calculations according to established methods [1] to obtain amajLime's relative quantum yield to a fluorescein standard with a quantum yield of 0.5. Thus, our contribution to the characterization of the amajLime basic part BBa_K includes an independent measurement the amajLime's spectral data and relative quantum yield determination.
A summary of the data added onto the Registry page for BBa_K1033916 is shown below. See Results for a detailed description of the methodology used:
Figure 2:Emission and Excitation spectra of amajLime in Tris-buffered Saline (50 mmol Tris-Cl pH 9.1, 150 mmol NaCl)
Discussion
Our results are consistent with the data previously obtained by Hong Kong 201, however, our absorbance data does display offset error at longer wavelengths. This error may be attributed to inefficient purification of amajLime, differences in pathlength of the samples, and other confounding factors. Our determined relative quantum yield for amajLime of 0.65 with a standard quantum yield of 0.5 is also consistent with the previously published value of 0.71 for wild type amajLime [2].
References
[1] P. J. Cranfill et al., “Quantitative assessment of fluorescent proteins,” Nat. Methods, vol. 13, no. 7, pp. 557–562, Jul. 2016.
[2] J. N. Henderson and S. J. Remington, “Crystal structures and mutational analysis of amFP486, a cyan fluorescent protein from Anemonia majano,” Proc. Natl. Acad. Sci. U. S. A., vol. 102, no. 36, pp. 12712–12717, Sep. 2005.
