Identification and characterization of a basic thaumatin-like protein (TLP 2) as an allergen in sapodilla plum (Manilkara zapota)
Article first published online: 5 DEC 2013
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Molecular Nutrition & Food Research
Volume 58, Issue 4, pages 894–902, April 2014
How to Cite
Hegde, V. L., Ashok Kumar, H. G., Sreenath, K., Hegde, M. L. and Venkatesh, Y. P. (2014), Identification and characterization of a basic thaumatin-like protein (TLP 2) as an allergen in sapodilla plum (Manilkara zapota). Mol. Nutr. Food Res., 58: 894–902. doi: 10.1002/mnfr.201300261
- Issue published online: 1 APR 2014
- Article first published online: 5 DEC 2013
- Manuscript Accepted: 9 SEP 2013
- Manuscript Revised: 6 AUG 2013
- Manuscript Received: 12 APR 2013
- Council of Scientific & Industrial Research (CSIR)
- Arginine-rich protein;
- Fruit allergen;
- Thaumatin-like protein
Cases of oral allergy syndrome following the ingestion of sapodilla plum (Manilkara zapota) have been reported rarely. As the causative allergens are not known, the main objective of this study was to identify and characterize the important allergens in sapodilla.
Methods and results
Allergy to sapodilla was diagnosed by case history, skin prick test, and serum allergen–specific IgE. The allergen was detected by IgE immunoblotting, purified on SP–Sepharose and characterized by native/SDS–PAGE, IEF, MS, and amino acid composition. Several cases of allergy to sapodilla fruit were identified; majority of the sapodilla-allergic subjects (6/7) experienced typical oral allergy syndrome symptoms, and allergen–specific IgE to the purified protein was positive. The allergen has a pI ≥9.5 and high contents of arginine, threonine, glycine, and cysteine. Circular dichroism revealed a secondary structure rich in beta sheets/turns. Based on its N-terminal sequence of A-T-F-D-I-Q-N-N-C-X-Y-, the allergen (21 578 Da) was identified as a thaumatin-like protein by homology.
The causative allergen in sapodilla plum has been identified and characterized as a highly basic thaumatin-like protein belonging to the pathogenesis-related protein (PR–5) family, which has been recognized as a new family of conserved, cross-reactive plant allergens.