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spinqualitylabelsall models 1k9u, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure of the Calcium-Binding Pollen Allergen Phl p 7 (Polcalcin) at 1.75 Angstroem

Overview

The timothy grass pollen allergen Phl p 7 assembles most of the IgE, epitopes of a novel family of 2 EF-hand calcium-binding proteins and, therefore represents a diagnostic marker allergen and vaccine candidate, for immunotherapy. Here we report the first three-dimensional structure of, a representative of the 2 EF-hand allergen family, Phl p 7, in the, calcium-bound form. The protein occurs as a novel dimer assembly with, unique features: in contrast to well known EF-hand proteins such as, calmodulin, parvalbumin or the S100 proteins, Phl p 7 adopts an extended, conformation. Two protein monomers assemble in a head-to-tail arrangement, with domain-swapped EF-hand pairing. The intertwined dimer adopts a, barrel-like structure with an extended hydrophobic cavity providing a, ligand-binding site. Calcium binding acts as a conformational switch, between an open and a closed dimeric form of Phl p 7. These findings are, interesting in the context of lipid- and calcium-dependent pollen tube, growth. Furthermore, the structure of Phl p 7 allows for the rational, development of vaccine strategies for treatment of sensitized allergic, patients.

About this Structure

1K9U is a Single protein structure of sequence from Phleum pratense with SO4 and CA as ligands. Full crystallographic information is available from OCA.

Reference

The cross-reactive calcium-binding pollen allergen, Phl p 7, reveals a novel dimer assembly., Verdino P, Westritschnig K, Valenta R, Keller W, EMBO J. 2002 Oct 1;21(19):5007-16. PMID:12356717

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