11-01: Structural and computational characterization of a lytic polysaccharide monooxygenase from the white rot fungus Phanerochaete chrysosporium

Lytic polysaccharide monooxygenase (LPMO) comprise a newly discovered class of enzymes that cleave recalcitrant polysaccharides such as cellulose and chitin by an oxidative mechanism. [1] These enzymes have attracted significant interest from the biofuels community because they have been shown to act synergistically with conventional cellulases.

Very little is currently known about the mechanisms that these enzymes employ, but recent industrial developments indicate that they will be of major importance for the production of biofuels biomass. One of the key questions around LPMO action is why many organisms have multiple LPMO genes. [2] To answer this question will require structure-function studies of multiple LPMOs from well-characterized organisms.

This paper describes the first LPMO structure from the fungus Phanerochaete chrysosporium, which has a repertoire of more than ten LPMO genes. All studies of LPMOs to date have examined model cellulose or chitin systems. Here we elucidate the product distribution of an LPMO enzyme directly from a biomass substrate. A key outstanding issue is how LPMOs interact with and bind to their insoluble substrates. Here, we have for the first time, conducted molecular dynamics simulations of these systems on the cellulose surface, and revealed molecular-level details of the enzyme-substrate interaction.

References

1. Vaaje-Kolstad G. et al. (2010) An oxidative enzyme boosting the enzymatic conversion of recalcitrant polysaccharides. Science 330: 219-222.

2. Floudas D et al. (2012) The Paleozoic origin of enzymatic lignin decomposition reconstructed from 31 fungal genomes. Science 336: 1715-1719.