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2opo

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[[Image:2opo.gif|left|200px]]
[[Image:2opo.gif|left|200px]]
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{{Structure
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|PDB= 2opo |SIZE=350|CAPTION= <scene name='initialview01'>2opo</scene>, resolution 1.75&Aring;
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The line below this paragraph, containing "STRUCTURE_2opo", creates the "Structure Box" on the page.
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|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>
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{{STRUCTURE_2opo| PDB=2opo | SCENE= }}
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|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2opo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2opo OCA], [http://www.ebi.ac.uk/pdbsum/2opo PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2opo RCSB]</span>
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'''Crystal structure of the calcium-binding pollen allergen Che a 3'''
'''Crystal structure of the calcium-binding pollen allergen Che a 3'''
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==Overview==
==Overview==
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BACKGROUND: Little is known about the molecular properties of chenopod allergens. Recently, profilin and 2 EF-hand calcium-binding protein (polcalcin) have been shown to play a role in chenopod pollinosis. OBJECTIVE: We sought to analyze these panallergens in chenopod pollen and to evaluate their involvement in the allergy to this biologic source. METHODS: Profilin and polcalcin were purified to homogeneity and characterized by using spectrometric and chemical methods. Immunologic analyses were performed by means of immunoblotting, ELISA, and competitive inhibition assays with olive profilin- and polcalcin-specific rabbit polyclonal antibodies and sera from patients with chenopod allergy. cDNAs encoding these proteins were cloned by means of PCR and sequenced. RESULTS: Purified Che a 2 (profilin) and Che a 3 (polcalcin) exhibited prevalences of 55% and 46%, respectively, in patients (n=104) hypersensitive to chenopod pollen. Both purified allergens individually inhibited the IgE binding to the whole pollen extract and showed strong cross-reactivity with the corresponding olive pollen profilin (Ole e 2) and polcalcin (Ole e 3). Chenopod profilin consists of a 131-amino-acid chain that displays identities of approximately 75% and 82% with pollen and food profilins, respectively. Che a 3 (86 amino acids) displays similarity (65% to 82% identity) with polcalcins from pollens of olive, birch, alder, rapeseed, and timothy. CONCLUSION: Profilin and polcalcin are relevant panallergens in chenopod pollen and good candidates to be involved in IgE cross-reactivity with other pollen sources, thus explaining the highly frequent polysensitization of patients allergic to chenopod.
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Two EF-hand calcium-binding allergens (polcalcins) occur in the pollen of a wide variety of unrelated plants as highly cross-reactive allergenic molecules. We report the expression, purification, immunological characterization, and the 1.75-A crystal structure of recombinant Che a 3 (rChe a 3), the polcalcin from the weed Chenopodium album. The three-dimensional structure of rChe a 3 resembles an alpha-helical fold that is essentially identical with that of the two EF-hand allergens from birch pollen, Bet v 4, and timothy grass pollen, Phl p 7. The extensive cross-reactivity between Che a 3 and Phl p 7 is demonstrated by competition experiments with IgE Abs from allergic patients as well as specific Ab probes. Amino acid residues that are conserved for the two EF-hand allergen family were identified in multiple sequence alignments of polcalcins from 15 different plants. Next, the three-dimensional structures of rChe a 3, rPhl p 7, and rBet v 4 were used to identify conserved amino acids with high surface exposition to visualize surface patches as potential targets for the polyclonal IgE Ab response of allergic patients. The essentially identical three-dimensional structures of rChe a 3, rPhl p 7, and rBet v 4 explain the extensive cross-reactivity of allergic patients IgE Abs with two EF-hand allergens from unrelated plants. In addition, analyzing the three-dimensional structures of cross-reactive Ags for conserved and surface exposed amino acids may be a first approach to mapping the conformational epitopes on disease-related Ags that are recognized by polyclonal patient Abs.
==About this Structure==
==About this Structure==
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2OPO is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Chenopodium_album Chenopodium album]. This structure supersedes the now removed PDB entry 1PMZ. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OPO OCA].
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2OPO is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Chenopodium_album Chenopodium album]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1pmz 1pmz]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OPO OCA].
==Reference==
==Reference==
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Profilin (Che a 2) and polcalcin (Che a 3) are relevant allergens of Chenopodium album pollen: isolation, amino acid sequences, and immunologic properties., Barderas R, Villalba M, Pascual CY, Batanero E, Rodriguez R, J Allergy Clin Immunol. 2004 Jun;113(6):1192-8. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15208604 15208604]
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Three-dimensional structure of the cross-reactive pollen allergen Che a 3: visualizing cross-reactivity on the molecular surfaces of weed, grass, and tree pollen allergens., Verdino P, Barderas R, Villalba M, Westritschnig K, Valenta R, Rodriguez R, Keller W, J Immunol. 2008 Feb 15;180(4):2313-21. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18250440 18250440]
[[Category: Chenopodium album]]
[[Category: Chenopodium album]]
[[Category: Single protein]]
[[Category: Single protein]]
[[Category: Keller, W.]]
[[Category: Keller, W.]]
[[Category: Verdino, P.]]
[[Category: Verdino, P.]]
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[[Category: calcium-binding protein]]
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[[Category: Allergen]]
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[[Category: dimer]]
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[[Category: Calcium-binding protein]]
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[[Category: domain-swapping]]
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[[Category: Dimer]]
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[[Category: ef-hand]]
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[[Category: Domain-swapping]]
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[[Category: Ef-hand]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:21:19 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Apr 9 14:40:42 2008''

Revision as of 11:40, 9 April 2008

Template:STRUCTURE 2opo

Crystal structure of the calcium-binding pollen allergen Che a 3


Overview

Two EF-hand calcium-binding allergens (polcalcins) occur in the pollen of a wide variety of unrelated plants as highly cross-reactive allergenic molecules. We report the expression, purification, immunological characterization, and the 1.75-A crystal structure of recombinant Che a 3 (rChe a 3), the polcalcin from the weed Chenopodium album. The three-dimensional structure of rChe a 3 resembles an alpha-helical fold that is essentially identical with that of the two EF-hand allergens from birch pollen, Bet v 4, and timothy grass pollen, Phl p 7. The extensive cross-reactivity between Che a 3 and Phl p 7 is demonstrated by competition experiments with IgE Abs from allergic patients as well as specific Ab probes. Amino acid residues that are conserved for the two EF-hand allergen family were identified in multiple sequence alignments of polcalcins from 15 different plants. Next, the three-dimensional structures of rChe a 3, rPhl p 7, and rBet v 4 were used to identify conserved amino acids with high surface exposition to visualize surface patches as potential targets for the polyclonal IgE Ab response of allergic patients. The essentially identical three-dimensional structures of rChe a 3, rPhl p 7, and rBet v 4 explain the extensive cross-reactivity of allergic patients IgE Abs with two EF-hand allergens from unrelated plants. In addition, analyzing the three-dimensional structures of cross-reactive Ags for conserved and surface exposed amino acids may be a first approach to mapping the conformational epitopes on disease-related Ags that are recognized by polyclonal patient Abs.

About this Structure

2OPO is a Single protein structure of sequence from Chenopodium album. This structure supersedes the now removed PDB entry 1pmz. Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of the cross-reactive pollen allergen Che a 3: visualizing cross-reactivity on the molecular surfaces of weed, grass, and tree pollen allergens., Verdino P, Barderas R, Villalba M, Westritschnig K, Valenta R, Rodriguez R, Keller W, J Immunol. 2008 Feb 15;180(4):2313-21. PMID:18250440 Page seeded by OCA on Wed Apr 9 14:40:42 2008

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