1K9U

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

Summary for 1K9U

• Entry DOI: 10.2210/pdb1k9u/pdb
• Descriptor: Polcalcin Phl p 7, SULFATE ION, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: pollen allergen, calcium-binding, ef-hand, cross-reactivity, allergen
• Biological source: Phleum pratense (timothy grass)
• Total number of polymer chains: 2
• Total formula weight: 17817.89

Authors

Verdino, P.,Westritschnig, K.,Valenta, R.,Keller, W. (deposition date: 2001-10-30, release date: 2003-04-30, Last modification date: 2024-03-13)

Primary citation

Verdino, P.,Westritschnig, K.,Valenta, R.,Keller, W.
The cross-reactive calcium-binding pollen allergen, Phl p 7, reveals a novel dimer assembly
EMBO J., 21:5007-5016, 2002

PubMed Abstract: 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.

PubMed: 12356717
DOI: 10.1093/emboj/cdf526

Experimental method

X-RAY DIFFRACTION (1.75 Å)