Affiliation:
1. Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid, Spain
Abstract
Several allergenic proteins, such as the 1,3-β-glucanases, have been associated with plant defence responses. Ole e 9 (46kDa) is a 1,3-β-glucanase and major allergen from olive pollen, which is a principal cause of allergy in Mediterranean countries. Its C-terminal segment (101 amino acid residues) has been produced as a recombinant polypeptide in the yeast Pichia pastoris. The cDNA encoding the polypeptide was inserted into the plasmid vector pPICZα-A and overexpressed in KM71 yeast cells. The recombinant product was purified by size-exclusion chromatography followed by reversed-phase HPLC. Edman degradation, MS and CD were used to determine molecular properties of the recombinant polypeptide, which exhibited 16% α-helix and 30% β-sheet as regular elements of secondary structure. Disulphide bridges of the molecule were determined at positions Cys-14—Cys-76, Cys-33—Cys-94 and Cys-39—Cys-48. The high IgE-binding capability of the recombinant C-terminal segment of Ole e 9 against sera from Ole e 9-sensitive individuals, which was determined by immunoblotting and ELISA inhibition, supported the proper folding of the polypeptide and the maintenance of antigenic properties that it exhibits as a part of the whole allergen. These data indicated that this portion of Ole e 9 constitutes an independent domain, which could be used to study its three-dimensional structure and function, as well as for clinical purposes such as diagnosis and specific immunotherapy. Since it shows sequence similarity with portions of 1,3-β-glucanases from plant tissues and the Gas/Phr/Epd protein families involved in yeast morphogenesis, we suggest that this domain could play an equivalent functional role within these enzymes.
Subject
Cell Biology,Molecular Biology,Biochemistry
Cited by
32 articles.
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