Cloning and Characterization of Luciferase from the Chinese Firefly Lamprigera yunnana

Lamprigera (Lampyridae) is a small genus with only 17 species distributing in Asian countries. Its larviform females and alate males can produce continuously strong yellow-green light at night. However, no luciferase gene was reported for this genus and its subfamily-level phylogenetic position still remains uncertain. Here, we cloned the luciferase gene from one Chinese species, Lamprigera yunnana, by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). This luciferase includes 551 deduced amino acids (AA) with the sequence identity of 71.8-76.8%, 67.5-70.7%, 68.4-75.3%, 77.8% and 59.5% to those from Lampyrinae, Luciolinae, Ototretinae, Cyphonocerinae and Photurinae, respectively. Phylogenetic analyses of deduced AA of luciferases suggest that Lamprigera locates outside Lampyrinae, in which it was originally placed in traditional taxonomy. The luciferase was produced in vitro as recombinant protein, and its biochemical properties were characterized. It possesses significant luminescence activity at pH 7.8, and its K_M for D-luciferin and ATP are 61 μm and 122 μm, respectively. It shows the highest activity at 37°C and is completely inactivated at 55°C. It is pH-sensitive with the maximum emission spectrum of 566 nm at pH 7.8. Our data provide new insights into Lamprigera luciferase and its phylogenetic position.