Excitation transfer in the in-vitro reaction of photobacterium luciferase bioluminescence

摘要

Fluorescence dynamics methods are used to probe the mechanism by which the chemi-energized intermediates of the bacterial luciferase catalyzed oxidation of FMNH$-2$/ and tetradecanal are able to excite the ligand of lumazine protein to its first excited singlet state. A fluorescence dynamics study of the effect of lumazine protein on the reaction of several types of luciferase has recently been published (Biochemistry 30 6825, 1991). This present report examines the case of the Photobacterium leiognathi luciferase reaction in more detail. The fluorescence anisotropy of a mixture of this luciferase fluorescent transient mixed with lumazine protein decays rapidly with a correlation time of 5 ns, interpreted as due to energy transfer. There is no sign of a longer time corresponding to the rotation of the proteins themselves. No rise time of the lumazine (acceptor) fluorescence on exciting into the fluorescent transient (donor) absorption is measureable, so that no straightforward estimate of the energy transfer rate can be made.