Interaction between luciferases from various species of bioluminescent bacteria and the yellow fluorescent protein of Vibrio fischeri strain Y-1.

The interaction of the Yellow Fluorescent Protein (YFP) from Vibrio fischeri strain Y-1 with luciferases from other bioluminescent bacterial strains have been studied. Addition of purified YFP to a Y-1 luciferase assay results in enhancement of the intensity of blue (484 nm) bioluminescence and a new peak in the emission spectrum at about 540 nm. The bimodal spectrum also resulted when the luciferase used in the reaction was isolated from the species V. fischeri ATCC 7744, V. fischeri Y-1, Photobacterium phosphoreum, and P. leiognathi, but not when the luciferase was from V. harveyi. Analysis of the degree of enhancement versus the amount of YFP added yielded a binding constant for YFP to luciferase (V. fischeri Y-1 and V. harveyi) of about 2.4-4.0 microM.