CONSTRUCTION AND CHARACTERIZATION OF HYBRID LUCIFERASES CODED BY lux GENES FROM Xenorhabdus luminescens AND Vibrio fischeri

Abstract— Molecular cloning techniques were employed to obtain hybrid luciferases with their α and β subunits encoded by lux A and lux B genes, respectively, from Xenorhabdus luminescens strain HW or Vibrio fischeri. Although the two wild-type luminous bacteria are phylogenetically diverged, the hybrid luciferase Xf comprising an α from V. fischeri and a β from X. luminescens HW were both functional in bioluminescence. Their general kinetic properties were close to the wild type enzymes from which the α subunit was derived. The X. luminescens HW enzyme is distinct in having a high optimal temperature for in vitro bioluminescence, a high thermal stability and a sensitivity to aldehyde substrate inhibition. Comparisons of the Xf and VI hybrid luciferases with the two wild-type enzymes indicated that these unusual properties of the X. luminescens HW luciferase originated primarily from the α subunit.