QM/MM Study of Bioluminescent Systems

Abstract

Bioluminescence is a chemical reaction of (usually multi-steps) oxidation of a substrate (luciferin) in the presence of an enzyme (luciferase). The oxidation leads to a product in its electronic excited state, which releases the chemical energy in the form of light. Quantum mechanic/molecular mechanic (QM/MM) methods are approaches of choice to study bioluminescent reactions as they allow the study of electronic transitions taking into account the protein environment. In this chapter, we will present the QM/MM methods that are used for studying bioluminescent reactions. How the enzymatic environment can be taken into account? What are the difficulties to describe the excited states? Which experimental data are needed to be able to perform studies of bioluminescent systems? How simulations can help interpreting and predicting experimental observation? Tentative answers to these questions and some examples of studies of firefly’s bioluminescent system have been reported in this chapter.