Identification of a serine protease inhibitor homologue in Bird's Nest by an integrated proteomics approach.
For centuries, the edible nests of Collocalia spp. ("Bird's Nests") have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical studies indicated that in Singapore, Bird's Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird's Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird's Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization--time of flight--mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white.
Ou
K
K
Bioprocessing Technology Center, Singapore National University of Singapore. btcoukl@nus.edu.sg
Seow
T K
TK
Liang
R C
RC
Lee
B W
BW
Goh
D L
DL
Chua
K Y
KY
Chung
M C
MC
D000485:Allergens / Q000032:analysis*; D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds; D004527:Egg Proteins / Q000032:analysis*; D015387:Egg Proteins, Dietary; D006967:Hypersensitivity / Q000097:blood* / Q000276:immunology; D015151:Immunoblotting / Q000379:methods; D008969:Molecular Sequence Data; D020543:Proteome / Q000032:analysis*; D020539:Sequence Analysis, Protein; D015842:Serine Proteinase Inhibitors / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
D000485:Allergens; D004527:Egg Proteins; D015387:Egg Proteins, Dietary; D020543:Proteome; D015842:Serine Proteinase Inhibitors; C004224:ovoinhibitor