title: Structure and function of α-glucan debranching enzymes.
abstract: α-Glucan debranching enzymes hydrolyse α-1,6-linkages in starch/glycogen, thereby, playing a central role in energy metabolism in all living organisms. They belong to glycoside hydrolase families GH13 and GH57 and several of these enzymes are industrially important. Nine GH13 subfamilies include α-glucan debranching enzymes; isoamylase and glycogen debranching enzymes (GH13_11); pullulanase type I/limit dextrinase (GH13_12-14); pullulan hydrolase (GH13_20); bifunctional glycogen debranching enzyme (GH13_25); oligo-1 and glucan-1,6-α-glucosidases (GH13_31); pullulanase type II (GH13_39); and α-amylase domains (GH13_41) in two-domain amylase-pullulanases. GH57 harbours type II pullulanases. Specificity differences, domain organisation, carbohydrate binding modules, sequence motifs, three-dimensional structures and specificity determinants are discussed. The phylogenetic analysis indicated that GH13_39 enzymes could represent a "missing link" between the strictly α-1,6-specific debranching enzymes and the enzymes with dual specificity and α-1,4-linkage preference.
authors.affiliation: Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark. mariesofiemoller@gmail.com.|Center for Molecular Protein Science, Department of Chemistry, Lund University, 221 00, Lund, Sweden. mariesofiemoller@gmail.com.
authors.forename: Marie Sofie
authors.initials: MS
authors.lastname: Møller
authors.affiliation: Global Research Unit, Department of Large Protein Biophysics and Formulation, Novo Nordisk A/S, Novo Nordisk Park, 2760, Måløv, Denmark.
authors.forename: Anette
authors.initials: A
authors.lastname: Henriksen
authors.affiliation: Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
authors.forename: Birte
authors.initials: B
authors.lastname: Svensson
mesh_terms: D005936:Glucans / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D007221:Industry; D040681:Structural Homology, Protein
chemical_list: D005936:Glucans; D006003:Glycogen; D006026:Glycoside Hydrolases; C100181:pullulanase
keywords: Carbohydrate binding modules; Domain architecture; Glycoside hydrolase family 13 subfamilies; Multi-domain three-dimensional structure; Phylogeny; Sequence motifs and determinants; Structure–function relationship; Substrate specificity