1k9u
From Proteopedia
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. 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 Page seeded by OCA on Fri May 2 22:29:03 2008
