AA13 lytic polysaccharide monooxygenase, and similar proteins
This family contains starch-degrading (also called starch-active) lytic polysaccharide monooxygenase (LPMO), a representative of the new CAZy AA13 family and classified as an auxiliary activity enzyme. This enzyme acts on alpha-linked glycosidic bonds and displays a binding surface that is quite different from those of LPMOs acting on beta-linked glycosidic bonds, indicating that the AA13 family proteins interact with their substrate in a distinct fashion. The active site contains an amino-terminal histidine-ligated mononuclear copper. This enzyme generates aldonic acid-terminated malto-oligosaccharides from retrograded starch and significantly boosts the conversion of this recalcitrant substrate to maltose by beta-amylase.
Comment:LPMOs are copper-dependent enzymes that oxidatively cleave polysaccharides
Comment:copper coordination is provided by the terminal NH2 and the pi-N of the side chain of the N-terminal histidine, the tau-N of a further histidine side chain and a tyrosine; latter 2 residues are invariant across the AA13 family
Jiyao W et al.(2023). "The conserved domain database in 2023.",