TY - JOUR
T1 - Characterization and gene cloning of an acidic thaumatin-like protein (TLP 1), an allergen from sapodilla fruit (Manilkara zapota)
AU - Ashok Kumar, Hassan G.
AU - Hegde, Venkatesh L.
AU - Shetty, Santoshkumar M.
AU - Venkatesh, Yeldur P.
N1 - Funding Information:
The assistance rendered by the staff of the Health Centre, CSIR-CFTRI, Mysore, India, is gratefully acknowledged. We thank the Council of Scientific & Industrial Research (CSIR), New Delhi, for financial support (Y.P.V., institutional project; H.G.A. and V.L. H., research fellowship). S.M.S. thanks the Department of Biotechnology (DBT), New Delhi for the award of a research fellowship. We gratefully acknowledge the assistance received from Dr. Purnima Tiku (Protein Chemistry & Technology Department, CSIR-CFTRI, Mysore) for protein analysis by electro-focusing. Thanks are also due to Dr. Ram Ra-jasekaran (Director, CSIR-CFTRI) and Dr. Asha Martin (Food Safety & Analytical Quality Control Laboratory Department, CSIR-CFTRI) for protein sequencing of SP2 component (28 kDa) and SP3 component (37 kDa) in this study.
PY - 2013
Y1 - 2013
N2 - 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.
AB - 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.
KW - Acidic TLP
KW - Exotic fruit
KW - Food allergen
KW - Manilkara zapota
KW - Oral allergy syndrome
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U2 - 10.2332/allergolint.12-OA-0522
DO - 10.2332/allergolint.12-OA-0522
M3 - Article
C2 - 24060761
AN - SCOPUS:84884957474
VL - 62
SP - 447
EP - 462
JO - Allergology International
JF - Allergology International
SN - 1323-8930
IS - 4
ER -