Resolution of the three-dimensional structures of beetle luciferases and related enzymes by X-ray crystallography: relationship between structure, bioluminescence spectra and oxygenase activity

Abstract

Bioluminescence is the emission of visible light by living organisms, which has important intra- and inter-specific communicative functions, among which are the sexual attraction, defense, camouflage and attraction of prey. A bioluminescent reaction involves, basically, oxygen oxidation of compounds generally known as luciferins. These reactions are catalyzed by enzymes called luciferases. In beetle luciferases, the structural determinants of bioluminescence spectra and pH sensitivity are still unclear. Luciferases that emit at the extremes of the bioluminescence spectra offer models to elucidate these determinants. Furthermore, the structural determinants and origin of oxygen / luciferase activity in luciferases and CoA ligases have not yet been determined. In this work, the green light-emitting luciferases of Pyrearinus termitilluminans, red light of Phrixotrix hirtus and pH-sensitive of Macrolampis sp2 in the presence of luciferin analogs or metals, will be crystallized to determine the three-dimensional structure and recognition of the active and binding sites of metals. It is expected that by comparing the three-dimensional structures obtained and those described in the literature we can identify the residues and catalytic groups responsible for oxygen activity and understand how the structure influences the emitted light spectrum. By understanding the relationship between structure and function of these proteins, it will be possible to increase their catalytic properties so that they can be used in biotechnological and biomedical applications.