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Oxidative Cleavage of Cellulose by Fungal Copper-Dependent Polysaccharide Monooxygenases
- Beeson, William
T., Phillips, Christopher M., Cate, Jamie H. D., Marletta, Michael A.
- Journal of the American Chemical Society 2012 v.134 no.2 pp. 890-892
- Neurospora crassa, cellobiose dehydrogenase, cellulose, fungi, glycosidic linkages, isotope labeling, oxygen, oxygenases, proteins
- Fungal-derived, copper-dependent polysaccharide monooxygenases (PMOs), formerly known as GH61 proteins, have recently been shown to catalyze the O₂-dependent oxidative cleavage of recalcitrant polysaccharides. Different PMOs isolated from Neurospora crassa were found to generate oxidized cellodextrins modified at the reducing or nonreducing ends upon incubation with cellulose and cellobiose dehydrogenase. Here we show that the nonreducing end product formed by an N. crassa PMO is a 4-ketoaldose. Together with isotope labeling experiments, further support is provided for a mechanism involving oxygen insertion and subsequent elimination to break glycosidic bonds in crystalline cellulose.