title: Lys89, Lys90, and Phe91 are critical core amino acid residues of the Pen ch 18 major fungal allergen recognized by human IgE antibodies.
abstract: A vacuolar serine protease (Pen ch 18) has been identified as a major allergen of Penicillium chrysogenum. The molecular features of antigenic determinant(s) on Pen ch 18 recognized by human IgE antibodies, however, have remained unclear. Here, we show that a dominant IgE epitope on the N-terminally processed Pen ch 18 allergen was narrowed down to residues 83-91. In addition, Lys89, Lys90, and possibly Phe91 were identified as the core residues. Substitution of Lys89, Lys90, or Phe91 with alanine can significantly reduce IgE-binding to Pen ch 18. Immunoblot inhibition confirmed that Lys89 and Phe91 played a significant role in IgE-binding against Pen ch 18. Molecular modeling suggests they are located on a loop-like structure at or near the surface of the major fungal allergen.
authors.affiliation: Department of Medical Research and Education, Taipei Veterans General Hospital, No. 201, Section 2, Shih Pai Road, Shih-Pai, Taipei 11217, Taiwan, ROC.
authors.forename: Tien-Tien
authors.initials: TT
authors.lastname: Cheng
authors.forename: Ming F
authors.initials: MF
authors.lastname: Tam
authors.forename: Hong
authors.initials: H
authors.lastname: Chou
authors.forename: Hsiao-Yun
authors.initials: HY
authors.lastname: Tai
authors.forename: Horng-Der
authors.initials: HD
authors.lastname: Shen