A view on the active site of firefly luciferase

The bioluminescent enzyme firefly luciferase has been the subject of detailed biochemical studies since the late 1940s. These studies have culminated in the cloning and sequence determination of some 161 different c-DNAs and/or genes for firefly luciferase and the determination of 6 crystallographic structures with and without reactants/products/analogs bound. This paper reviews these studies, searches for which amino acid residues are involved in the enzyme's action using chemical modification experiments, and analyzes the structure/function relationships of the various conserved amino acid residues. There are 71/550 amino acid residues conserved in the 161 different firefly luciferases. In my laboratory K-206, K-529, and R-437 were chemically modified; ATP inhibited these modifications suggesting that they are involved in the reaction. An integrated picture of the active site is postulated.