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The Gaussia Lucriferase and the bioluminescence reaction

The Gaussia luciferase (GLuc) was identified from the marine copepod Gaussia princeps. Discovered relatively recently, this luciferase has been attracting attention as a potential reporter protein [1]and as a useful tool for bio-imaging application. However, its biophysical properties remain to be fully characterized.[2]

GLuc shows the strongest bioluminescence intensity (over 200 fold the firefly and the Renilla luciferase bioluminescence activity). Moreover, this luciferase shows a narrow substrate specificity which is highly specific for native coelenterazine. Among all the others luciferase, GLuc has the highest ability to catalyze the oxidation of coelenterazine for the luminescence reaction and this catalysis activity was found to be highly stable under a wide range of temperatures and in an acidic environment. Its activity is however salt dependent (with the highest activity at 50mM NaCl), strongly inhibited by heavy metal ions (Cu2+) and stimulated by monovalent ions (Cl−, I−, Br−).[2][4]

Gluc Structure

[GLuc's sequence (mRNA, complete cds) was first reported in 1999. With a molecular mass of 19.9 kDa, it is the smallest known luciferase. This protein is composed of two domains (Domain1: 27–97; Domain 2: 98–168) linked together and precede by a pre-sequence (1 – 26). GLuc is predicted to be a helical protein, and sequence alignment predicts that each domain contains two intra-domain disulfide bonds and an inter-domain disulfide bond between cysteines C59 and C120. The highly conserved regions 52–77 in domain 1 and 123–148 in domain 2 seems to overlap with the active site. [2][4]

Gaussia Luciferase possesses a natural secretory signal and upon expression is secreted into the cell medium. Therefore, lysing cells in order to assay GLuc activity is not necessary.[2]

[1] Wille, T., Blank, K., Schmidt, C., Vogt, V., and Gerlach, R.G. (2012). Gaussia princeps Luciferase as a Reporter for Transcriptional Activity, Protein Secretion, and Protein-Protein Interactions in Salmonella enterica Serovar Typhimurium. Applied and Environmental Microbiology 78, 250–257 [2] Wu, N., Rathnayaka, T., and Kuroda, Y. (2015). Bacterial expression and re-engineering of Gaussia princeps luciferase and its use as a reporter protein. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 1854, 1392–1399. [3] Inouye, S., Sahara-Miura, Y., Sato, J., Iimori, R., Yoshida, S., and Hosoya, T. (2013). Expression, purification and luminescence properties of coelenterazine-utilizing luciferases from Renilla, Oplophorus and Gaussia: Comparison of substrate specificity for C2-modified coelenterazines. Protein Expression and Purification 88, 150–156. [4] S. Inouye, Y. Sahara, Identification of two catalytic domains in a luciferase secreted by the copepod Gaussia princeps, Biochem. Biophys. Res. Commun. 365 (2008) 96–101.