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Crystal structure and epitope analysis of house dust mite allergen Der f 21

DOI: 10.1038/s41598-019-40879-x DOI Help

Authors: Sze Lei Pang (Universiti Kebangsaan Malaysia) , Kok Lian Ho (Universiti Putra) , Jitka Waterman (Diamond Light Source) , Robert Paul Rambo (Diamond Light Source) , Aik-hong Teh (Universiti Sains Malaysia) , Indran Mathavan (Imperial College London; Research Complex at Harwell) , Gemma Harris (Research Complex at Harwel) , Konstantinos Beis (Research Complex at Harwell; Imperial College London) , Yee-how Say (Universiti Tunku Abdul Rahman (UTAR) Perak Campus) , Matta Sri Anusha (National University of Singapore) , Yang Yie Sio (National University of Singapore) , Fook Tim Chew (National University of Singapore) , Chyan Leong Ng (Universiti Kebangsaan Malaysia)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Scientific Reports , VOL 9

State: Published (Approved)
Published: March 2019

Open Access Open Access

Abstract: Group 21 and 5 allergens are homologous house dust mite proteins known as mid-tier allergens. To reveal the biological function of group 21 allergens and to understand better the allergenicity of the rDer f 21 allergen, we determined the 1.5 Å crystal structure of rDer f 21 allergen from Dermatophagoides farinae. The rDer f 21 protein consists of a three helical bundle, similar to available structures of group 21 and homologous group 5 allergens. The rDer f 21 dimer forms a hydrophobic binding pocket similar to the one in the Der p 5 allergen, which indicates that both of the homologous groups could share a similar function. By performing structure-guided mutagenesis, we mutated all 38 surface-exposed polar residues of the rDer f 21 allergen and carried out immuno-dot blot assays using 24 atopic sera. Six residues, K10, K26, K42, E43, K46, and K48, which are located in the region between the N-terminus and the loop 1 of rDer f 21 were identified as the major IgE epitopes of rDer f 21. Epitope mapping of all potential IgE epitopes on the surface of the rDer f 21 crystal structure revealed heterogeneity in the sIgE recognition of the allergen epitopes in atopic individuals. The higher the allergen-sIgE level of an individual, the higher the number of epitope residues that are found in the allergen. The results illustrate the clear correlation between the number of specific major epitope residues in an allergen and the sIgE level of the atopic population.

Journal Keywords: Immunology; Structural biology

Subject Areas: Biology and Bio-materials

Instruments: B21-High Throughput SAXS , I02-Macromolecular Crystallography