Peanut allergen Ara h 1 interacts with proanthocyanidins into higher molecular weight complexes.
Mildly extracted peanut allergen Ara h 1 was previously reported to occur as an oligomeric complex. In this paper we describe how the protein in this oligomeric complex interacts noncovalently with phenolic compounds of the proanthocyanidin type. These interactions are being disrupted during anion exchange chromatography, resulting in the dissociation of the oligomeric Ara h 1 complex into protein trimers. By use of the known three-dimensional structure of beta-conglycinin, a soy protein homologous to Ara h 1, proline-rich regions were observed in silico on both faces of its trimeric structure, which are conserved in Ara h 1. These proline-rich regions could explain the binding of proanthocyanidins to Ara h 1 and the formation of multiple Ara h 1 trimer complexes. This was supported by the observation that the addition of peanut proanthocyanidins to trimeric Ara h 1 and to beta-conglycinin resulted in the formation of soluble oligomeric protein complexes. The structurally related legumin proteins do not contain such proline-rich regions on both sides of the protein, and proanthocyanidins were shown to have a lower affinity for legumin proteins from peanuts and soybeans (peanut allergen Ara h 3 and soy glycinin, respectively). Ara h 1 present as the oligomeric complex is assumed to be the representative form of the allergen in which it is consumed by humans.
van Boxtel
Evelien L
EL
Laboratory of Food Chemistry, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
van den Broek
Lambertus A M
LA
Koppelman
Stef J
SJ
Vincken
Jean-Paul
JP
Gruppen
Harry
H
D000485:Allergens / Q000737:chemistry*; D052179:Antigens, Plant; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004347:Drug Interactions; D005916:Globulins / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry*; D008565:Membrane Proteins; D008958:Models, Molecular; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry*; D055314:Seed Storage Proteins; D030262:Soybean Proteins / Q000737:chemistry
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D005916:Globulins; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D044945:Proanthocyanidins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; C011474:glycinin