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Characterization and Gene Cloning of an Acidic Thaumatin-Like Protein (TLP 1), an Allergen from Sapodilla Fruit (Manilkara zapota)

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Relation http://ir.cftri.com/12195/
http://dx.doi.org/10.2332/allergolint.12-OA-0522
 
Title Characterization and Gene Cloning of
an Acidic Thaumatin-Like Protein
(TLP 1), an Allergen from Sapodilla
Fruit (Manilkara zapota)
 
Creator Ashok Kumar, Hassan G
Venkatesh, L. Hegde
Santoshkumar, M. Shetty
Venkatesh, Y. P.
 
Subject 12 Allergy & Toxicology
24 Fruits
 
Description Background: Allergy to sapodilla (Manilkara zapota) fruit ingestion is rare. An independent study from our
group has identified a basic thaumatin-like protein (TLP 2) as the major allergen. The present study was aimed
at identifying and characterizing additional allergens from sapodilla.
Methods: Allergic subjects were identified by case history, skin prick test (SPT) and allergen-specific IgE.
Sapodilla extract was fractionated using SP-Sepharose into 3 components (SP1, SP2 and SP3) which were
analyzed by native�SDS-PAGE, IgE-immunoblot, isoelectric focusing (IEF) and N-terminal sequencing. The
conserved regions of plant TLPs and the N-terminal sequence were used to design primers for PCR.
Results: SPT and ELISA confirmed a subject with oral allergy syndrome (OAS) to sapodilla and custard apple.
Two proteins (26.9 and 24.5 kDa; reducing conditions) were detected as allergens, of which the latter in SP2
has already been identified as basic TLP (TLP 2). The 26.9 kDa protein present in SP1 was identified as an
acidic TLP based on native PAGE, IEF and N-terminal sequencing. Presence of a basic β-1,3-glucanase in
SP3 was inferred by zymography. Sequence analysis of the genomic clone of the acidic TLP gene revealed
that it is intronless and non-glycosylated. Evolutionary relatedness to olive, grape and kiwi fruit allergenic TLPs
were inferred by phylogenetic analysis.
Conclusions: An acidic TLP (TLP 1) was identified as a new allergen in sapodilla. TLP 1 is a single polypeptide
(207 residues) belonging to the thaumatin family of the GH64-TLP-SF superfamily. Clinically, sapodilla
should be considered in the list of fruits causing OAS.
 
Date 2013
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://ir.cftri.com/12195/1/Allergology%20International%2C%20Volume%2062%2C%20Issue%204%2C%202013%2C%20Pages%20447-462.pdf
Ashok Kumar, Hassan G and Venkatesh, L. Hegde and Santoshkumar, M. Shetty and Venkatesh, Y. P. (2013) Characterization and Gene Cloning of an Acidic Thaumatin-Like Protein (TLP 1), an Allergen from Sapodilla Fruit (Manilkara zapota). Allergology International, 62 (4). pp. 447-462.