title: Fungal lytic polysaccharide monooxygenases bind starch and β-cyclodextrin similarly to amylolytic hydrolases.
abstract: Starch-binding modules of family 20 (CBM20) are present in 60% of lytic polysaccharide monooxygenases (LPMOs) catalyzing the oxidative breakdown of starch, which highlights functional importance in LPMO activity. The substrate-binding properties of starch-active LMPOs, however, are currently unexplored. Affinities and binding-thermodynamics of two recombinant fungal LPMOs toward starch and β-cyclodextrin were shown to be similar to fungal CBM20s. Amplex Red assays showed ascorbate and Cu-dependent activity, which was inhibited in the presence of β-cylodextrin and amylose. Phylogenetically, the clustering of CBM20s from starch-targeting LPMOs and hydrolases was in accord with taxonomy and did not correlate to appended catalytic activity. Altogether, these results demonstrate that the CBM20-binding scaffold is retained in the evolution of hydrolytic and oxidative starch-degrading activities.
authors.affiliation: Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: Laura
authors.initials: L
authors.lastname: Nekiunaite
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
authors.forename: Trine
authors.initials: T
authors.lastname: Isaksen
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
authors.forename: Gustav
authors.initials: G
authors.lastname: Vaaje-Kolstad
authors.affiliation: Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: Maher
authors.initials: M
authors.lastname: Abou Hachem
mesh_terms: D000688:Amylose / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain / Q000235:genetics; D003300:Copper / Q000737:chemistry; D019143:Evolution, Molecular; D006867:Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020082:Magnaporthe / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D011134:Polysaccharides; D013213:Starch / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D047392:beta-Cyclodextrins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011134:Polysaccharides; D047392:beta-Cyclodextrins; D003300:Copper; D013213:Starch; D000688:Amylose; D006899:Mixed Function Oxygenases; D006867:Hydrolases
keywords: AA13; CBM20; carbohydrate-binding module; lytic polysaccharide monooxygenase; starch binding; β-cyclodextrin