Research on the Structure of Peanut Allergen Protein Ara h1 Based on Aquaphotomics

Abstract

Peanut allergy is becoming a life-threatening disease that could induce severe allergic reactions in modern society, especially for children. The most promising method applied for deallergization is heating pretreatment. However, the mechanism from the view of spectroscopy has not been illustrated. In this study, near-infrared spectroscopy (NIRS) combined with aquaphotomics was introduced to help us understand the detailed structural changes information during the heating process. First, near-infrared (NIR) spectra of Ara h1 were acquired from 25 to 80°C. Then, aquaphotomics processing tools including principal component analysis (PCA), continuous wavelet transform (CWT), and two-dimensional correlation spectroscopy (2D-COS) were utilized for better understanding the thermodynamic changes, secondary structure, and the hydrogen bond network of Ara h1. The results indicated that about 55°C could be a key temperature, which was the structural change point. During the heating process, the hydrogen bond network was destroyed, free water was increased, and the content of protein secondary structure was changed. Moreover, it could reveal the interaction between the water structure and Ara h1 from the perspective of water molecules, and explain the effect of temperature on the Ara h1 structure and hydrogen-bonding system. Thus, this study described a new way to explore the thermodynamic properties of Ara h1 from the perspective of spectroscopy and laid a theoretical foundation for the application of temperature-desensitized protein products.

Identification of the Immunoglobulin E Epitope of Arginine Kinase, an Important Allergen from Crassostrea angulata

“…15 The tertiary structure of an allergen is usually maintained by chemical bonds, which mainly include hydrogen bonds, hydrophobic bonds, disulfide bonds, etc. 10,14,34 In this study, a variety of denaturants were used to destroy the tertiary structure of Cra a 2 and explore the effect of the tertiary structure destruction on immunoreactivity. The immunoreactivity of Cra a 2 decreased after SDS treatment.…”

Allergenicity of peanut allergens and its dependence on the structure

“…Ara h 1 accounts for 12%−16% of the total peanut protein content and can be recognized by more than 90% serum IgE from peanut‐allergic patients (Burks et al., 1995; Koppelman et al., 2001). Ara h 1 is a soluble glycoprotein found in the cotyledons of peanuts with a molecular mass of 63.5 kDa (Zhang, Liu, et al., 2021). The Ara h 1 monomer can form stable homotrimers or larger assemblies via noncovalent interactions, which resist GI digestion (van Boxtel et al., 2006).…”

Peanut protein – an underutilised by‐product with great potential: a review

“…Peanut allergy is considered to be one of the most severe food allergies with a prevalence around 2% (Li et al ., 2020a). Currently, strict avoidance is the only treatment and rescue medication upon accidental exposure to peanuts since peanut is a common food ingredient (Zhang et al ., 2021a). PP is mainly made of storage proteins, albumins and globulins.…”

“…Globulins (7S and 11S) comprise the majority of the total protein (~75%) (Ji et al ., 2017), and it is subdivided into vicilins (7S globulins) and legumins (11S globulins) (Mueller et al ., 2014). Thirteen proteins have been identified as allergens in peanuts (Zhang et al ., 2021a). Ara h 1, 2, 3 and 6 are considered the major allergens and are often associated with severe symptoms, while Ara h 5, 7, 8, 9, 10, 11 and 12/13 are considered minor allergens since they do not cause life‐threatening allergic reactions (Kim et al ., 2019).…”

“…Ara h 8 has been shown to have cross‐reactivity with from birch pollen (Bet v 1) (Palladino & Breiteneder, 2018). Ara h 5, also called peanut profilin, is associated with pollen allergy (profilins from grass and birch pollen, Phl p 12 and Bet v 2, respectively) (Zhang et al ., 2021a). Therefore, efficient mitigation strategies are of great interest to develop hypoallergenic PP.…”