INTERACTION OF PHOTOBACTERIUM-LEIOGNATHI AND VIBRIO-FISCHERI Y1 LUCIFERASES WITH FLUORESCENT (ANTENNA) PROTEINS - BIOLUMINESCENCE EFFECTS OF THE ALIPHATIC ADDITIVE

The kinetics of the bacterial bioluminescence reaction is altered in t he presence of the fluorescent (antenna) proteins, lumazine protein (L umP) from Photobacterium or the yellow fluorescence proteins (YFP) hav ing FMN or Rf bound, from Vibrio fischeri strain Y1, Depending on reac tion conditions, the bioluminescence intensity and its decay rate may be either enhanced or strongly quenched in the presence of the fluores cent proteins. These effects call be simply explained on the basis of the same protein-protein complex model that accounts for the biolumine scence spectral shifts induced by these fluorescent proteins. In such a complex, when the fluorophore evidently is in proximity to the lucif erase active site, it is expected that the on-off rate of certain alip hatic components of the reaction should be altered with a consequent s hift in the equilibria among the luciferase intermediates, as recently elaborated in a kinetic scheme, These aliphatic components are the bi oluminescence reaction substrate, tetradecanal or other long-chain ald ehyde, its carboxylic acid product, or dodecanol used as a stabilizer of the luciferase peroxyflavin. No evidence can be found or the protei n-protein interaction in the absence of the aliphatic component.