Structure and boosting activity of a starch-degrading lytic polysaccharide monooxygenase.

Leila Lo Leggio, Thomas J Simmons, Jens-Christian N Poulsen, Kristian E H Frandsen, Glyn R Hemsworth, Mary A Stringer, Pernille von Freiesleben, Morten Tovborg, Katja S Johansen, Leonardo De Maria, Paul V Harris, Chee-Leong Soong, Paul Dupree, Theodora Tryfona, Nicolas Lenfant, Bernard Henrissat, Gideon J Davies, Paul H Walton

Index: Nat. Commun. 6 , 5961, (2015)

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Abstract

Lytic polysaccharide monooxygenases (LPMOs) are recently discovered enzymes that oxidatively deconstruct polysaccharides. LPMOs are fundamental in the effective utilization of these substrates by bacteria and fungi; moreover, the enzymes have significant industrial importance. We report here the activity, spectroscopy and three-dimensional structure of a starch-active LPMO, a representative of the new CAZy AA13 family. We demonstrate that these enzymes generate aldonic acid-terminated malto-oligosaccharides from retrograded starch and boost significantly the conversion of this recalcitrant substrate to maltose by β-amylase. The detailed structure of the enzyme's active site yields insights into the mechanism of action of this important class of enzymes.