1h4b
From Proteopedia
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SOLUTION STRUCTURE OF THE BIRCH POLLEN ALLERGEN BET V 4
Overview
Birch pollinosis is one of the prevailing allergic diseases. In all, 5-20%, of birch pollinotics mount IgE antibodies against the minor birch pollen, allergen Bet v 4, a Ca2+-binding polcalcin. Due to IgE cross-reactivity, among the polcalcins these patients are polysensitized to various plant, pollens. Determination of the high-resolution structure of holo Bet v 4 by, heteronuclear NMR spectroscopy reveals a canonical two EF-hand assembly in, the open conformation with interhelical angles closely resembling holo, calmodulin. The polcalcin-specific amphipathic COOH-terminal alpha-helix, covers only a part of the hydrophobic groove on the molecular surface., Unlike the polcalcin Phl p 7 from timothy grass, which was recently shown, to form a domain-swapped dimer, the hydrodynamic parameters from NMR, relaxation, NMR translational diffusion, and analytical, ultracentrifugation indicate that both apo and holo Bet v 4 are, predominantly monomeric, raising the question of the physiological and, immunological significance of the dimeric form of these polcalcins, whose, physiological function is still unknown. The reduced helicity and heat, stability in the CD spectra, the poor chemical shift dispersion of the NMR, spectra, and the slightly increased hydrodynamic radius of apo Bet v 4, indicate a reversible structural transition upon Ca2+ binding, which, explains the reduced IgE binding capacity of apo Bet v 4. The remarkable, structural similarity of holo Bet v 4 and holo Phl p 7 in spite of, different oligomerization states explains the IgE cross-reactivity and, indicates that canonical monomers and domain-swapped dimers may be of, similar allergenicity. Together with the close structural homology to, calmodulin and the hydrophobic ligand binding groove this transition, suggests a regulatory function for Bet v 4.
About this Structure
1H4B is a Single protein structure of sequence from Betula pendula with CA as ligand. Full crystallographic information is available from OCA.
Reference
Solution structure, dynamics, and hydrodynamics of the calcium-bound cross-reactive birch pollen allergen Bet v 4 reveal a canonical monomeric two EF-hand assembly with a regulatory function., Neudecker P, Nerkamp J, Eisenmann A, Nourse A, Lauber T, Schweimer K, Lehmann K, Schwarzinger S, Ferreira F, Rosch P, J Mol Biol. 2004 Mar 5;336(5):1141-57. PMID:15037075
Page seeded by OCA on Tue Nov 20 16:24:57 2007
