Don't Fret! The Synthesis of a FRET Labeled Probe for the Identification of Lignin Depolymerization
Lignin, a complex polymer found in the cell walls of plants, is the second most abundant natural polymer, a major waste product of wood processing, and an underutilized source for biofuel production. In order to efficiently use it as an energy source, it is necessary to understand the pathways of lignin depolymerization and search for enzymes that are capable of depolymerization. This project attempts to synthesize a FRET labeled probe to find new enzymes in unexplored ecological systems. The FRET (Forster Resonance Energy Transfer) probe builds upon a lignin dimer, with the highly abundant β-O-4 linkage, that was previously shown to be cleaved by lignin peroxidase. This project is a continuation of a method development study aimed to incorporate a fluorophore molecule (TAMRA) on one end and a quencher molecule (BHQ-2) on the other to allow for in vivo digestion to be observed. When excited, this probe would transfer energy to a quencher molecule on the other end, which would absorb the fluorescence instead. When cleaved, the FRET pair of molecules would separate, stopping the energy transfer and allowing the probe to fluoresce. This probe would be useful for finding the precise location of evolutionary unique depolymerizing enzymes from organisms like termites and shipworms. We hypothesize these will be catalytically more proficient than the well-characterized lignin peroxidases from fungal sources. Identification of new, highly efficient lignin depolymerizing enzymes could improve the ability to use lignin for the production of biofuels and other usable organic molecules on an industrial scale.