title: A C4-oxidizing lytic polysaccharide monooxygenase cleaving both cellulose and cello-oligosaccharides.
abstract: Lignocellulosic biomass is a renewable resource that significantly can substitute fossil resources for the production of fuels, chemicals, and materials. Efficient saccharification of this biomass to fermentable sugars will be a key technology in future biorefineries. Traditionally, saccharification was thought to be accomplished by mixtures of hydrolytic enzymes. However, recently it has been shown that lytic polysaccharide monooxygenases (LPMOs) contribute to this process by catalyzing oxidative cleavage of insoluble polysaccharides utilizing a mechanism involving molecular oxygen and an electron donor. These enzymes thus represent novel tools for the saccharification of plant biomass. Most characterized LPMOs, including all reported bacterial LPMOs, form aldonic acids, i.e., products oxidized in the C1 position of the terminal sugar. Oxidation at other positions has been observed, and there has been some debate concerning the nature of this position (C4 or C6). In this study, we have characterized an LPMO from Neurospora crassa (NcLPMO9C; also known as NCU02916 and NcGH61-3). Remarkably, and in contrast to all previously characterized LPMOs, which are active only on polysaccharides, NcLPMO9C is able to cleave soluble cello-oligosaccharides as short as a tetramer, a property that allowed detailed product analysis. Using mass spectrometry and NMR, we show that the cello-oligosaccharide products released by this enzyme contain a C4 gemdiol/keto group at the nonreducing end.
authors: From the Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432 Ås, Norway.
authors: Trine
authors: T
authors: Isaksen
authors: Bjørge
authors: B
authors: Westereng
authors: Finn L
authors: FL
authors: Aachmann
authors: Jane W
authors: JW
authors: Agger
authors: Daniel
authors: D
authors: Kracher
authors: Roman
authors: R
authors: Kittl
authors: Roland
authors: R
authors: Ludwig
authors: Dietmar
authors: D
authors: Haltrich
authors: Vincent G H
authors: VG
authors: Eijsink
authors: Svein J
authors: SJ
authors: Horn
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D013058:Mass Spectrometry; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009492:Neurospora crassa / Q000201:enzymology* / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism
chemical_list: D056804:Biofuels; D009844:Oligosaccharides; D011134:Polysaccharides; D002244:Carbon; D002482:Cellulose; D006899:Mixed Function Oxygenases; D010100:Oxygen
keywords: AA10; AA9; Biofuel; CBM33; Cellulase; GH61; Lytic Polysaccharide Monooxygenase (LPMO); Mass Spectrometry (MS); Metalloenzymes; NMR