2CYG

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

Summary for 2CYG

• Entry DOI: 10.2210/pdb2cyg/pdb
• Descriptor: beta-1, 3-glucananse (2 entities in total)
• Functional Keywords: endo-beta-1, 3-glucanase, (beta-alpha)8-tim-barrel, b-cell epitopes, allergen, banana, hydrolase
• Biological source: Musa acuminata
• Total number of polymer chains: 1
• Total formula weight: 33442.40

Authors

Receveur-Brechot, V.,Czjzek, M.,Barre, A.,Roussel, A.,Peumans, W.J.,Van Damme, E.J.M.,Rouge, P. (deposition date: 2005-07-07, release date: 2005-11-22, Last modification date: 2023-10-25)

Primary citation

Receveur-Brechot, V.,Czjzek, M.,Barre, A.,Roussel, A.,Peumans, W.J.,Van Damme, E.J.M.,Rouge, P.
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
Proteins, 63:235-242, 2006

PubMed Abstract: 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.

PubMed: 16421930
DOI: 10.1002/prot.20876

Experimental method

X-RAY DIFFRACTION (1.45 Å)