Biomass processing: Mechanistic aspects of lytic polysaccharide monooxygenases
In a recent PNAS paper, the OxyMod team describes novel catalytic features of a lytic polysaccharide monooxygenase (LPMO) that may facilitate future applications of these enzymes in biomass processing.
The novel insights were obtained from the combination of structural studies by NMR (at OxyMod partner NTNU, who led this subproject), studies of active site electronics using EPR by collaborators at York University, and enzymological studies at NMBU. This is the second time this year that the OxyMod team has published novel insights into LPMO functionality in PNAS.
Structural data for an LPMO (BlLPMO10A) obtained by NMR. The bound copper ion is shown as an orange sphere. Structures of apo- and Cu(I)-BlLPMO10A. (A) Ensemble of the 10 lowest-energy conformers of apo-BlLPMO10A (PDB ID code 5LW4). (B) Overlay of apo-BlLPMO10A (green) and Cu(I)-BlLPMO10A (PDB ID code 6TWE; blue). (C) Zoomed-in view of the overlay in B showing details of the catalytic copper site. (D) Ensemble of five lowest-energy conformers of Cu(I)-BlLPMO10A, showing the copper site.
In OxyMod the idea is to study the interplay between multiple redox enzymes involved in degradation of lignocellulosic biomass. The connections between the various enzymes in this enzyme system involve transport of electrons and the production and consumption of various reactive oxygen species. The most important group of enzymes under study are the lytic polysaccharide monooxygenases (LPMOs), which were discovered at NMBU in 2010 and which have revolutionized our thinking about enzymes degrade recalcitrant polysaccharides such as cellulose. Although not recognized until 2010, today, it seems that complex systems of interacting redox enzymes may become crucial for developing commercially viable biorefining processes and OxyMod aims at unraveling and applying these enzyme systems.
Mechanistic basis of substrate-O2 coupling within a chitin-active lytic polysaccharide monooxygenase: An integrated NMR/EPR study
Proc Natl Acad Sci U S A. 2020 Aug 11;117(32):19178-19189. doi:10.1073/pnas.2004277117.
Courtade G, Ciano L, Paradisi A, Lindley PJ, Forsberg Z, Sørlie M, Wimmer R, Davies GJ, Eijsink VGH, Walton PH, Aachmann FL.