Crystal Structure of the Major Allergen from Fire Ant Venom, Sol i 3

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• 作者：Sivaraman Padavattan ; Margit Schmidt ; Donald R. Hoffman ; Zora Marković ; -Housley
• 关键词：major fire ant allergen ; Sol i 3 ; crystal structure ; cross-reactivity
• 刊名：Journal of Molecular Biology
• 出版年：2008
• 出版时间：31 October 2008
• 年：2008
• 卷：383
• 期：1
• 页码：178-185
• 全文大小：3147 K

文摘

Fire ant venom is an extremely potent allergy-inducing agent containing four major allergens, Sol i 1 to Sol i 4, which are the most frequent cause of hypersensitivity reactions to hymenoptera in the southern USA. The crystal structure of recombinant (Baculovirus) major fire ant allergen Sol i 3 has been determined to a resolution of 3.1 Å by the method of molecular replacement. The secondary-structure elements of Sol i 3 are arranged in an α–β–α sandwich fold consisting of a central antiparallel β-sheet surrounded on both sides by α helices. The overall structure is very similar to that of the homologous wasp venom allergen Ves v 5 with major differences occurring in the solvent-exposed loop regions that contain amino acid insertions. Consequently, the limited conservation of surface chemical properties and topology between Sol i 3 and Ves v 5 may explain the observed lack of relevant cross-reactivity. It is concluded that Sol i 3 recognizes immunoglobulin E antibodies with a distinct set of its own epitopes, which are different from those of Ves v 5. Indeed, the molecular area in Sol i 3 covered by non-conserved residues is large enough to accommodate four unique Sol i 3 epitopes.