2cyg
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(New page: 200px<br /><applet load="2cyg" size="350" color="white" frame="true" align="right" spinBox="true" caption="2cyg, resolution 1.45Å" /> '''Crystal structure at...)
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Revision as of 16:51, 29 January 2008
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Crystal structure at 1.45- resolution of the major allergen endo-beta-1,3-glucanase of banana as a molecular basis for the latex-fruit syndrome
Overview
Resolution of the crystal structure of the banana fruit, endo-beta-1,3-glucanase by synchrotron X-ray diffraction at 1.45-A, resolution revealed that the enzyme possesses the eightfold beta/alpha, architecture typical for family 17 glycoside hydrolases. The, electronegatively charged catalytic central cleft harbors the two, glutamate residues (Glu94 and Glu236) acting as hydrogen donor and, nucleophile residue, respectively. Modeling using a beta-1,3 linked glucan, trisaccharide as a substrate confirmed that the enzyme readily, accommodates a beta-1,3-glycosidic linkage in the slightly curved, catalytic groove between the glucose units in positions -2 and -1 because, of the particular orientation of residue Tyr33 delimiting subsite -2. The, location of Phe177 in the proximity of subsite +1 suggested that the, banana glucanase might also cleave beta-1,6-branched glucans. Enzymatic, assays using pustulan as a substrate demonstrated that the banana, glucanase can also cleave beta-1,6-glucans as was predicted from docking, experiments. Similar to many other plant endo-beta-1,3-glucanases, the, banana glucanase exhibits allergenic properties because of the occurrence, of well-conserved IgE-binding epitopes on the surface of the enzyme. These, epitopes might trigger some cross-reactions toward IgE antibodies and thus, account for the IgE-binding cross-reactivity frequently reported in, patients with the latex-fruit syndrome.
About this Structure
2CYG is a Single protein structure of sequence from Musa acuminata. Active as Glucan endo-1,3-beta-D-glucosidase, with EC number 3.2.1.39 Full crystallographic information is available from OCA.
Reference
Crystal structure at 1.45-A resolution of the major allergen endo-beta-1,3-glucanase of banana as a molecular basis for the latex-fruit syndrome., Receveur-Brechot V, Czjzek M, Barre A, Roussel A, Peumans WJ, Van Damme EJ, Rouge P, Proteins. 2006 Apr 1;63(1):235-42. PMID:16421930
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