Atomistic Insights into Photoprotein Formation: Computational Prediction of the Properties of Coelenterazine and Oxygen Binding in Obelin

Bioluminescence in marine systems is dominated by the use of one ligand for light production, coelenterazine. The bioluminescent reaction of coelenterazine is an enzyme catalysed, oxidative decarboxylation. During the reaction coelenterazine reacts with molecular oxygen to form carbon dioxide, coelenteramide and light. One such class of bioluminescent systems is the Ca[sup]2+-regulated photoproteins. These proteins, rather than continuously processing substrate, bind 2-hydroperoxycoelenterazine as an intermediate along the reaction pathway. The reaction is halted here until an external stimulus triggers the continuation of the bioluminescent reaction. There are currently no reported experimental, atomistic descriptions of the states that lead to this ternary michaelis complex. This study utilises computational techniques to develop an atomistic description of the complex of coelenterazine with one photoprotein, obelin.