Oxygen Activation at the Active Site of a Fungal Lytic Polysaccharide Monooxygenase. (22nd December 2016)

• Record Type: Journal Article
• Authors: O'Dell, William B.; Agarwal, Pratul K.; Meilleur, Flora
• Is Part Of: Angewandte Chemie. Volume 129:Number 3(2017)
• Page Start: 785
• Page End: 788
• Publication Date: 2016-12-22
• Subjects: Kupfer -- Oxidoreduktasen -- Polysaccharid-Monooxygenasen -- Proteinstrukturen -- Sauerstoffaktivierung; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201610502
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Lytic polysaccharide monooxygenases have attracted vast attention owing to their abilities to disrupt glycosidic bonds via oxidation instead of hydrolysis and to enhance enzymatic digestion of recalcitrant substrates including chitin and cellulose. We have determined high‐resolution X‐ray crystal structures of an enzyme from Neurospora crassa in the resting state and of a copper(II) dioxo intermediate complex formed in the absence of substrate. X‐ray crystal structures also revealed "pre‐bound" molecular oxygen adjacent to the active site. An examination of protonation states enabled by neutron crystallography and density functional theory calculations identified a role for a conserved histidine in promoting oxygen activation. These results provide a new structural description of oxygen activation by substrate free lytic polysaccharide monooxygenases and provide insights that can be extended to reactivity in the enzyme–substrate complex. Abstract : Aufspüren von Sauerstoff : Röntgenkristallographie liefert die erste Struktur einer lytischen Polysaccharid‐Monooxygenase (LPMO) mit einer gebundenen aktivierten Dioxospezies in der Ebene der Histidinklammer (siehe Strukturen, rechts: O rot, Cu kupferfarben, N blau, C grün). Eine Präbindungsstelle für molekularen Sauerstoff wird ebenfalls identifiziert und mit Neutronenproteinkristallographie und DFT‐Rechnungen (links) charakterisiert.