3EQN

Crystal structure of beta-1,3-glucanase from Phanerochaete chrysosporium (Lam55A)

Summary for 3EQN

• Entry DOI: 10.2210/pdb3eqn/pdb
• Related: 3EQO
• Descriptor: Glucan 1,3-beta-glucosidase, beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ZINC ION, ... (7 entities in total)
• Functional Keywords: tandem beta-helix domains, glycosidase, hydrolase
• Biological source: Phanerochaete chrysosporium (White-rot fungus)
• Total number of polymer chains: 2
• Total formula weight: 163073.32

Authors

Ishida, T.,Fushinobu, S.,Kawai, R.,Kitaoka, M.,Igarashi, K.,Samejima, M. (deposition date: 2008-10-01, release date: 2009-02-03, Last modification date: 2024-10-09)

Primary citation

Ishida, T.,Fushinobu, S.,Kawai, R.,Kitaoka, M.,Igarashi, K.,Samejima, M.
Crystal structure of glycoside hydrolase family 55 beta -1,3-glucanase from the basidiomycete Phanerochaete chrysosporium
J.Biol.Chem., 284:10100-10109, 2009

PubMed Abstract: Glycoside hydrolase family 55 consists of beta-1,3-glucanases mainly from filamentous fungi. A beta-1,3-glucanase (Lam55A) from the Basidiomycete Phanerochaete chrysosporium hydrolyzes beta-1,3-glucans in the exo-mode with inversion of anomeric configuration and produces gentiobiose in addition to glucose from beta-1,3/1,6-glucans. Here we report the crystal structure of Lam55A, establishing the three-dimensional structure of a member of glycoside hydrolase 55 for the first time. Lam55A has two beta-helical domains in a single polypeptide chain. These two domains are separated by a long linker region but are positioned side by side, and the overall structure resembles a rib cage. In the complex, a gluconolactone molecule is bound at the bottom of a pocket between the two beta-helical domains. Based on the position of the gluconolactone molecule, Glu-633 appears to be the catalytic acid, whereas the catalytic base residue could not be identified. The substrate binding pocket appears to be able to accept a gentiobiose unit near the cleavage site, and a long cleft runs from the pocket, in accordance with the activity of this enzyme toward various beta-1,3-glucan oligosaccharides. In conclusion, we provide important features of the substrate-binding site at the interface of the two beta-helical domains, demonstrating an unexpected variety of carbohydrate binding modes.

PubMed: 19193645
DOI: 10.1074/jbc.M808122200

Experimental method

X-RAY DIFFRACTION (1.7 Å)