title: The directionality of processive enzymes acting on recalcitrant polysaccharides is reflected in the kinetic signatures of oligomer degradation.
abstract: The enzymatic degradation of the closely related insoluble polysaccharides; cellulose (β(1-4)-linked glucose) by cellulases and chitin (β(1-4)-linked N-acetylglucosamine) by chitinases, is of large biological and economical importance. Processive enzymes with different inherent directionalities, i.e. attacking the polysaccharide chains from opposite ends, are crucial for the efficiency of this degradation process. While processive cellulases with complementary functions differ in structure and catalytic mechanism, processive chitinases belong to one single protein family with similar active site architectures. Using the unique model system of Serratia marcescens with two processive chitinases attacking opposite ends of the substrate, we here show that different directionalities of processivity are correlated to distinct differences in the kinetic signatures for hydrolysis of oligomeric tetra-N-acetyl chitotetraose.
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
authors.forename: Anne Grethe
authors.initials: AG
authors.lastname: Hamre
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schaupp
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway. Electronic address: morten.sorlie@nmbu.no.
authors.forename: Morten
authors.initials: M
authors.lastname: Sørlie
mesh_terms: D001704:Biopolymers / Q000378:metabolism*; D002384:Catalysis; D020134:Catalytic Domain; D002480:Cellulase / Q000737:chemistry / Q000378:metabolism*; D002688:Chitinases / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D011134:Polysaccharides / Q000378:metabolism*; D011487:Protein Conformation; D012706:Serratia marcescens / Q000201:enzymology
chemical_list: D001704:Biopolymers; D011134:Polysaccharides; D002688:Chitinases; D002480:Cellulase
keywords: Glycoside hydrolase; Kinetic; Processivity; Recalcitrant polysaccharide