Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedGlycoside 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. Crystal structure of glycoside hydrolase family 55 {beta}-1,3-glucanase from the basidiomycete Phanerochaete chrysosporium.,Ishida T, Fushinobu S, Kawai R, Kitaoka M, Igarashi K, Samejima M J Biol Chem. 2009 Apr 10;284(15):10100-9. Epub 2009 Feb 4. PMID:19193645[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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