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Biochemistry. 2013 Jun 11;52(23):3963-73. doi: 10.1021/bi400141u. Epub 2013 May 30.

A route from darkness to light: emergence and evolution of luciferase activity in AMP-CoA-ligases inferred from a mealworm luciferase-like enzyme.

Author information

1
Graduate Program of Biotechnology and Environmental Monitoring, Federal University of São Carlos (UFSCar), Rodovia João Leme dos Santos, km 110, Itinga, Sorocaba, SP, Brazil. viviani@ufscar.br

Abstract

The origin of luciferases and of bioluminescence is enigmatic. In beetles, luciferases seem to have evolved from AMP-CoA-ligases. How the new oxygenase luminogenic function originated from AMP-ligases leading to luciferases is one of the most challenging mysteries of bioluminescence. Comparison of the cloned luciferase-like enzyme from the nonluminescent Zophobas morio mealworm and beetle luciferases showed that the oxygenase activity may have emerged as a stereoselective oxidative drift with d-luciferin, a substrate that cannot be easily thioesterified to CoA as in the case of the l-isomer. While the overall kcat displayed by beetle luciferases is orders of magnitude greater than that of the luciferase-like enzyme, the respective oxidation rates and quantum yields of bioluminescence are roughly similar, suggesting that the rate constant of the AMP-ligase activity exerted on the new d-luciferin substrate in beetle protoluciferases was the main enzymatic property that suffered optimization during the evolution of luciferases. The luciferase-like enzyme and luciferases boost the rate of luciferyl-adenylate chemiluminescent oxidation by factors of 10(6) and 10(7), respectively, as compared to the substrate spontaneous oxidation in buffer. A similar enhancement of luciferyl-adenylate chemiluminescence is provided by nucleophilic aprotic solvents, implying that the peptide bonds in the luciferin binding site of beetle luciferase could provide a similar catalytically favorable environment. These data suggest that the luciferase-like enzyme and other similar AMP-ligases are potential alternative oxygenases. Site-directed mutagenesis studies of the luciferase-like enzyme and the red light-producing luciferase of Phrixotrix hirtus railroadworm confirm here a critical role for T/S345 in luciferase function. Mutations such as I327T/S in the luciferase-like enzyme, which simultaneously increases luciferase activity and promotes blue shifts in the emission spectrum, could have been critical for evolving functional bioluminescence from red-emitting protoluciferases. Through the combination of I327T/S mutations and N-terminal fusion, the luminescence activity of this enzyme was increased to visible levels, with the development of a totally new orange-emitting luciferase. These results open the possibility of engineering luciferase activity in a set of AMP-CoA-ligases.

PMID:
23705763
DOI:
10.1021/bi400141u
[Indexed for MEDLINE]

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