“…Several lines of evidence indicate that delivery of luciferin from the binding protein to the luciferase as well as modulation of bioluminescence spectra as a result of energy transfer to the antenna proteins, involves protein-protein interactions (Morise et al, 1974;Ward andCormier, 1976, 1978;Nicolas et al, 1991;Cutler, 1995;Schultz et al, 2005;Titushin et al, 2008Titushin et al, , 2010Stepanyuk et al, 2009;. The interactions are of a transient nature, with K D in the range of 10 −6 -10 −3 mol/L, which highly impedes direct detection of the complexes, or their structural studies with Xray crystallography or NMR methods.…”