Cloning, expression and immunological characterisation of Coc n 1, the first major allergen from Coconut pollen. (March 2021)

• Record Type: Journal Article
• Authors: Saha, Bodhisattwa; Karmakar, Bijoya; Bhattacharya, Swati Gupta
• Is Part Of: Molecular immunology. Volume 131(2021)
• Page Start: 33
• Page End: 43
• Publication Date: 2021-03
• Subjects: Allergen -- Vicilin -- Immunoglobulin E (IgE) -- Sequence similarity networks -- Epitope mapping -- Coconut pollen; Immunochemistry -- Periodicals; Molecular biology -- Periodicals; Immunochemistry -- Periodicals; Allergy and Immunology -- Periodicals; Molecular Biology -- Periodicals; Immunochimie -- Périodiques; Biologie moléculaire -- Périodiques; Immunochemistry; Molecular biology; Periodicals; Electronic journals; 571.96
• DOI: 10.1016/j.molimm.2020.12.026
• Languages: English
• ISSNs: 0161-5890

Abstract

Graphical abstract: Highlights: Coc n 1, the first allergen from Coconut pollen belongs to the cupin superfamily. Recombinant Coc n 1 retains allergenicity. Three immunodominant epitopes mapped on the surface of Coc n 1. Coc n 1 is evolutionarily distant from known cupin domain containing allergens. Abstract: Coconut pollen has been documented to be a major contributor to the aeroallergen load in India, causing respiratory allergy in a large cohort of susceptible individuals. Here, we report the identification of the first major allergen from Coconut pollen, Coc n 1. The full-length sequence of the allergen was determined from previously identified peptides and overexpressed in E . coli . Recombinant Coc n 1 folded into a trimer and was found to possess allergenicity equivalent to its natural counterpart. Proteolytic processing of Coc n 1 led to the formation of an immunodominant ∼20 kDa C-terminal subunit and the site of cleavage was determined by amino acid microsequencing. Five linear IgE binding epitopes were predicted and mapped on the homology modelled structure of Coc n 1. Amongst three immunodominant epitopes, two were present towards the C-terminal end. Coc n 1 was found to belong to the highly diverse cupin superfamily and mimics its structure with known 7S globulin or vicilin allergens but lacks sequence similarity. Using sequence similarity networks, Coc n 1 clustered as a separate group containing unannotated cupin domain proteins and did not include known vicilin allergens except Gly m Bd 28 kDa, a Soybean major allergen. 7S globulins are major storage proteins and food allergens, but presence of such protein in pollen grains is reported for the first time. Further study on Coc n 1 may provide insights into its function in pollen grains and also in the development of immunotherapy to Coconut pollen allergy.