Generation of thermostable monomeric luciferases from Photorhabdus luminescens.
Bacterial luciferases and the genes encoding these light-emitting enzymes have an increasing number of applications in biological sciences. Temperature lability and the heterodimeric nature of these luciferases have been the major obstacles for their widespread use, for instance, as genetic reporters. Escherichia coli expressing wild-type Photorhabdus luminescens luciferase was found to produce eight times more light than the corresponding Vibrio harveyi luciferase clone in vivo at 37 degrees C. Three monomeric luciferases were created by translationally fusing the two genes encoding luxA and luxB proteins of P. luminescens. These clones were equally active in producing light in vivo when cultivated at 37 degrees C compared to cultivation at 30 degrees C. The fusion containing the longest linker showed the highest activity. In vitro, the monomeric luciferases were less active having at best 20% of activity of the wild-type enzyme due to the partial formation of insoluble aggregates. The results suggest that P. luminescens luciferase and monomeric derivatives thereof should be more suitable than the corresponding V. harveyi enzyme to be used as reporters in cell types which need cultivation at elevated temperatures.
Department of Biochemistry and Pharmacy, Abo Akademi University, FIN-20520, Turku, Finland.
Annette
A
Westerlund-Karlsson
Petri
P
Saviranta
Matti
M
Karp
D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D017930:Genes, Reporter; D008156:Luciferases / Q000235:genetics* / Q000378:metabolism*; D008163:Luminescent Measurements; D020637:Photorhabdus / Q000201:enzymology*; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013696:Temperature
D011993:Recombinant Fusion Proteins; D008156:Luciferases