6.4 Properties of Celery Profilin
6.4.1 Molecular Biological Properties
Celery Profilin | References | ||||||||||||
Allergen Nomenclature Api g 4 | (1) Larsen & Lowenstein 2000 | ||||||||||||
Isoallergens and Variants
Double band in SDS-PAGE (1, 2) |
(1) Vallier
et al. 1992
(2) Jankiewicz et al. 1998 |
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Molecular Mass
calculated: 14.3 kDa (3) SDS-PAGE: 15 kDa (1), 15-16 kDa (2) |
(1) Vallier
et al. 1992
(2) Jankiewicz et al. 1998 (3) Scheurer et al. 2000 |
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Isoelectric
Point
calculated: pI 4.54 (2) 2D-PAGE: pI 5.80 - 5.90 (1) |
(1) Vallier
et al. 1992
(2) Scheurer et al. 2000 |
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Amino Acid Sequence,mRNA, and
cDNA
|
(1) Scheurer et al. 2000 | ||||||||||||
recombinant Protein
Expression in Escherichia coli: PCR amplification of cDNA and expression of rApi g 4 in E.coli BL21DE3 using a modified pET-30a vector (1) |
(1) Scheurer et al. 2000 | ||||||||||||
Biological Function
Profilin family (1) |
(1) Vallier et al. 1992 | ||||||||||||
Sequence Homology
aa sequence identities to birch pollen profilin (Bet v 2) 80%, soybean profilin (Gly m 3) 78%, wheat profilin 78%, maize profilin 77%, kidney bean 76%, and barley profilin 75% (1, 2) aa sequence identity to human profilin: 33% (2) |
(1) BLAST at NBCI
(2) Scheurer et al. 2000 |
6.4.2 Allergenic Properties
Celery Profilin | References |
Frequency of Sensitization
IgE-binding to profilin in appr. 23-58% of patients (1) |
(1) see 6.1 Sensitization to Celery Allergens |
IgE-Binding Mimotope
A synthetic peptide (CAISGGYPVC) defined by phage display (using random nonapeptide libraries screened with anti- profilin antibodies from an exclusively profilin allergic patient) inhibited IgE binding to celery tuber profilin (immunoblot). This peptide is considered to mimic a common conformational IgE epitope of profilins (1) |
(1) Leitner et al. 1998b |
Allergenicity of recombinant Api g 4
(1) 22 celery allergic patients (DBPCFC positive): 5 sera bound to natural and rApi g 4 in SDS-PAGE immunoblot and to rApi g 4 in EAST; inhibition of IgE binding from 1 patient's serum to rApi g 4 by native celery extract and rApi g 4 and to native Api g 4 from celery extract by rApi g 4 (immunoblot) (2) 23% of 13 celery allergic patients (DBPCFC positive) and 88% of 8 birch profilin (Bet v 2) reactive sera reacted to rApi g 4 (immunoblot); IgE binding to rApi g 4 completely inhibited by celery extract in 9 sera and nearly completely by rBet v 2 in 2 sera; partial inhibition by rBet v 2 in 7 sera (immunoblot inhibition); complete inhibition of IgE binding to natural Api g 4 by rApi g 4 (2 sera and pooled serum, immunoblot inhibition); EAST inhibition with 1 serum (rApi g 4 vs. rBet v 2); Similar potencies of rApi g 4 and rBet v 2 in histamine release from basophils from 1 patient |
(1) Lüttkopf
et al. 2000
(2) Scheurer et al. 2000 |
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