posted on 2021-05-26, 20:26authored byDanijela Apostolovic, Justin T. Marsh, Joe Baumert, Steve L. Taylor, Adrie Westphal, Harmen de Jongh, Phil Johnson, Govardus A.H. de Jong, Stef J. Koppelman
2S
albumins are important peanut allergens. Within this protein
family, Ara h 2 and Ara h 6 have been described in detail, but Ara
h 7 has received little attention. We now describe the first purification
of Ara h 7 and its characterization. Two Ara h 7 isoforms were purified
from peanuts. Mass spectrometry revealed that both the isoforms have
a post-translation cleavage, a hydroxyproline modification near the N-terminus, and four disulfide bonds. The secondary structure
of both Ara h 7 isoforms is highly comparable to those of Ara h 2
and Ara h 6. Both Ara h 7 isoforms bind IgE, and Ara h 7 is capable
of inhibiting the binding between Ara h 2 and IgE, suggesting at least
partially cross-reactive IgE epitopes. Ara h 7 was found in all main
market types of peanut, at comparable levels. This suggests that Ara
h 7 is a relevant allergen from the peanut 2S albumin protein family.