12th International Symposium on Bioluminescence & Chemiluminescence

Symposium abstracts:

Mechanistic and mutagenesis studies of firefly luciferase bioluminescence color

Branchini, B.R., Murtiashaw, M.H., Southworth, T.L, Ruggiero, M.C.

Dept. of Chemistry, Connecticut College, New London, CT 06320, USA

Email: brbra@conncoll.edu

Beetle luciferases use the same luciferin substrate to naturally display light ranging in color from green (l_max ~530 nm) to red (l_max ~635 nm). We have prepared the adenylate of D-5,5-dimethylluciferin and have shown that it is transformed into the putative emitter 5,5-dimethyloxyluciferin in bioluminescence reactions catalyzed by luciferases from Photinus pyralis and the green light-emitting click beetle. 5,5-Dimethyloxyluciferin is constrained to exist in the keto form and fluoresces in the red. However, biolumi-nescence spectral measurements revealed that green light emission was produced by the firefly enzyme and red light was observed with the click beetle protein. These results and others from mutational studies of active site residues, including Gly246, are the basis of a new explanation of firefly bioluminescence color that we will present.

This is a preprint of an article accepted for publication in Luminescence: Copyright 2001 John
Wiley & Sons, Ltd (Wiley website)