Quantum yield improvement of red-light-emitting firefly luciferin analogues for in vivo bioluminescence imaging

• DOI: 10.1016/j.tet.2017.11.051
• Publication Date: 2017-11-22T02:30:20Z
• Authors: Masahiro Kiyama; Satoshi Iwano; Satoshi Otsuka; Shijia W. Lu; Rika Obata; Atsushi Miyawaki; Takashi Hirano; Shojiro A. Maki
• Keywords: Luciferin; Quantum yield; Photoprotein; Light emission; Bioluminescence imaging

Abstract The dimethylamino group of AkaLumine ((4S)-2-[(1E,3E)-4-[4-(dimethylamino)phenyl]-1,3-butadien-1-yl]-4,5-dihydro-4-thiazolecarboxylic acid), a red-light-emitting firefly luciferin analogue, was replaced by cyclic amino groups (1-pyrrolidinyl, 1-piperidino, 1-azepanyl, and 4-morpholino) to give AkaLumine analogues exhibiting desirable bioluminescence with emission maxima in the red region (656–667 nm). In particular, a bioluminescence reaction of 1-pyrrolidinyl analogue with a recombinant Photinus pyralis luciferase showed a higher quantum yield than that with AkaLumine, giving an improved bioluminescence intensity. The 1-pyrrolidinyl analogue also showed the strongest luminescence in whole-body luciferase-expressing mice among the analogues, indicating that a quantum yield improvement of a luciferin analogue is effective to increase bioluminescence imaging intensity.