4DNS

Crystal structure of Bermuda grass isoallergen BG60 provides insight into the various cross-allergenicity of the pollen group 4 allergens

Summary for 4DNS

• Entry DOI: 10.2210/pdb4dns/pdb
• Descriptor: FAD-linked oxidoreductase BG60, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, FLAVIN-ADENINE DINUCLEOTIDE, ... (5 entities in total)
• Functional Keywords: fad binding domain, oxidoreductase
• Biological source: Cynodon dactylon (Bermuda grass)
• Total number of polymer chains: 2
• Total formula weight: 112698.66

Authors

Huang, T.H.,Peng, H.J.,Su, S.N.,Liaw, S.H. (deposition date: 2012-02-08, release date: 2012-12-05, Last modification date: 2024-10-30)

Primary citation

Huang, T.H.,Peng, H.J.,Su, S.N.,Liaw, S.H.
Various cross-reactivity of the grass pollen group 4 allergens: crystallographic study of the Bermuda grass isoallergen Cyn d 4.
Acta Crystallogr.,Sect.D, 68:1303-1310, 2012

PubMed Abstract: The structure of Cyn d 4, the group 4 allergen from Bermuda grass, is reported at 2.15 Å resolution and is the first crystal structure of a naturally isolated pollen allergen. A conserved N-terminal segment that is only present in the large isoallergens forms extensive interactions with surrounding residues and hence greatly enhances the structural stability of the protein. Cyn d 4 contains an FAD cofactor that is covalently linked to His88 and Cys152. To date, all identified bicovalent flavoproteins are oxidases and their substrates are either sugars or secondary metabolites. A deep large hydrophobic substrate-binding cleft is present. Thus, Cyn d 4 may be an oxidase that is involved in the biosynthesis of a pollen-specific metabolite. Cyn d 4 shares ~70% sequence identity with the Pooideae group 4 allergens. Various cross-reactivities between grass pollen group 4 allergens have previously been demonstrated using sera from allergic patients. The protein surface displays an unusually large number of positively charged clusters, reflecting the high pI of ~10. 38 decapeptides that cover the solvent-accessible sequences did not show any significant IgE-binding activity using sera with high Cyn d 4 reactivity from four patients, suggesting that the IgE epitopes of Cyn d 4 are predominantly conformational in nature. Several group 4 structures were then modelled and their potential cross-reactive and species-specific IgE epitopes were proposed.

PubMed: 22993084
DOI: 10.1107/S0907444912027552

Experimental method

X-RAY DIFFRACTION (2.15 Å)