A <i>Photinus pyralis</i> and <i>Luciola italica</i> Chimeric Firefly Luciferase Produces Enhanced Bioluminescence

We report the enhanced bioluminescence properties of a chimeric enzyme (PpyLit) that contains the N-domain of recombinant <i>Photinus pyralis</i> luciferase joined to the C-domain of recombinant <i>Luciola italica</i> luciferase. Compared to the <i>P. pyralis</i> enzyme, the novel PpyLit chimera exhibited 1.8-fold enhanced flash-height specific activity, 2.0-fold enhanced integration-based specific activity, 2.9-fold enhanced catalytic efficiency (<i>k</i><sub>cat</sub>/<i>K</i><sub>m</sub>), and a 1.4-fold greater bioluminescence quantum yield. The results of this study provide an underlying basis of this unusual example of a chimeric enzyme with enhanced catalytic properties that are not simply the sum of the contributions of the two luciferases.