title: X-ray crystal structures of Phanerochaete chrysosporium Laminarinase 16A in complex with products from lichenin and laminarin hydrolysis.
abstract: The 1,3(4)-beta-D-glucanases of glycoside hydrolase family 16 provide useful examples of versatile yet specific protein-carbohydrate interactions. In the present study, we report the X-ray structures of the 1,3(4)-beta-D-glucanase Phanerochaete chrysosporium Laminarinase 16A in complex with beta-glucan products from laminarin (1.6 A) and lichenin (1.1 A) hydrolysis. The G6G3G3G glucan, in complex with the enzyme, showed a beta-1,6 branch in the acceptor site. The G4G3G ligand-protein complex showed that there was no room for a beta-1,6 branch in the -1 or -2 subsites; furthermore, the distorted residue in the -1 subsite and the glucose in the -2 subsite required a beta-1,3 bond between them. These are the first X-ray crystal structures of any 1,3(4)-beta-D-glucanase in complex with glucan products. They provide details of both substrate and product binding in support of earlier enzymatic evidence.
authors.affiliation: Department of Molecular Biology, University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Vasur
authors.forename: Rie
authors.initials: R
authors.lastname: Kawai
authors.forename: Evalena
authors.initials: E
authors.lastname: Andersson
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Igarashi
authors.forename: Mats
authors.initials: M
authors.lastname: Sandgren
authors.forename: Masahiro
authors.initials: M
authors.lastname: Samejima
authors.forename: Jerry
authors.initials: J
authors.lastname: Ståhlberg
mesh_terms: D044602:Cellulases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005936:Glucans / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D008024:Ligands; D008958:Models, Molecular; D020075:Phanerochaete / Q000201:enzymology*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D005656:Fungal Proteins; D005936:Glucans; D008024:Ligands; D011134:Polysaccharides; C008247:laminaran; D044602:Cellulases; C015968:lichenin