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2S Albumin Storage Proteins: What Makes them Food Allergens?

Moreno FJ, Clemente A - Open Biochem J (2008)

Bottom Line: This review describes the main biochemical, structural and functional properties of these proteins thought to play a role in determining their potential allergenicity. 2S albumins are considered to sensitize directly via the gastrointestinal tract (GIT).The flexible and solvent-exposed hypervariable region of these proteins is immunodominant and has the ability to bind IgE from allergic patients sera.Finally, the interaction of these proteins with other components of the food matrix might influence the absorption rates of immunologically reactive 2S albumins but also in their immune response.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Fermentaciones Industriales (CSIC), C/ Juan de la Cierva 3, 28006 Madrid, Spain.

ABSTRACT
2S albumin storage proteins are becoming of increasing interest in nutritional and clinical studies as they have been reported as major food allergens in seeds of many mono- and di-cotyledonous plants. This review describes the main biochemical, structural and functional properties of these proteins thought to play a role in determining their potential allergenicity. 2S albumins are considered to sensitize directly via the gastrointestinal tract (GIT). The high stability of their intrinsic protein structure, dominated by a well-conserved skeleton of cysteine residues, to the harsh conditions present in the GIT suggests that these proteins are able to cross the gut mucosal barrier to sensitize the mucosal immune system and/or elicit an allergic response. The flexible and solvent-exposed hypervariable region of these proteins is immunodominant and has the ability to bind IgE from allergic patients sera. Several linear IgE-binding epitopes of 2S albumins spanning this region have been described to play a major role in allergenicity; the role of conformational epitopes of these proteins in food allergy is far from being understood and need to be investigated. Finally, the interaction of these proteins with other components of the food matrix might influence the absorption rates of immunologically reactive 2S albumins but also in their immune response.

No MeSH data available.


Related in: MedlinePlus

Schematic ribbon representation of the recombinant castor bean 2S allergen Ric c 3 (PDB entry: 1PSY) [ 42].
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Figure 4: Schematic ribbon representation of the recombinant castor bean 2S allergen Ric c 3 (PDB entry: 1PSY) [ 42].

Mentions: 2S albumins adopt a common and compact three-dimensional structural scaffold comprising a bundle of five α-helices displayed in different regions (helices Ia, Ib, II, III and IV) and a C-terminal loop folded in a right-handed superhelix stabilized by four conserved disulphide bonds. Connecting the α-helices III and IV, there is an exposed and relatively short segment known as “hypervariable region” which has been described to be the most important antigenic region of the 2S albumins. However, its variability in length and amino acid composition observed in 2S albumins from different plant species suggests that it does not play any role in determining the folded structure [42]. As example, Fig. (4) shows the three-dimensional structure of the recombinant castor bean 2S allergen Ric c 3 (RCSB PDB entry: 1PSY) [42].


2S Albumin Storage Proteins: What Makes them Food Allergens?

Moreno FJ, Clemente A - Open Biochem J (2008)

Schematic ribbon representation of the recombinant castor bean 2S allergen Ric c 3 (PDB entry: 1PSY) [ 42].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2570561&req=5

Figure 4: Schematic ribbon representation of the recombinant castor bean 2S allergen Ric c 3 (PDB entry: 1PSY) [ 42].
Mentions: 2S albumins adopt a common and compact three-dimensional structural scaffold comprising a bundle of five α-helices displayed in different regions (helices Ia, Ib, II, III and IV) and a C-terminal loop folded in a right-handed superhelix stabilized by four conserved disulphide bonds. Connecting the α-helices III and IV, there is an exposed and relatively short segment known as “hypervariable region” which has been described to be the most important antigenic region of the 2S albumins. However, its variability in length and amino acid composition observed in 2S albumins from different plant species suggests that it does not play any role in determining the folded structure [42]. As example, Fig. (4) shows the three-dimensional structure of the recombinant castor bean 2S allergen Ric c 3 (RCSB PDB entry: 1PSY) [42].

Bottom Line: This review describes the main biochemical, structural and functional properties of these proteins thought to play a role in determining their potential allergenicity. 2S albumins are considered to sensitize directly via the gastrointestinal tract (GIT).The flexible and solvent-exposed hypervariable region of these proteins is immunodominant and has the ability to bind IgE from allergic patients sera.Finally, the interaction of these proteins with other components of the food matrix might influence the absorption rates of immunologically reactive 2S albumins but also in their immune response.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Fermentaciones Industriales (CSIC), C/ Juan de la Cierva 3, 28006 Madrid, Spain.

ABSTRACT
2S albumin storage proteins are becoming of increasing interest in nutritional and clinical studies as they have been reported as major food allergens in seeds of many mono- and di-cotyledonous plants. This review describes the main biochemical, structural and functional properties of these proteins thought to play a role in determining their potential allergenicity. 2S albumins are considered to sensitize directly via the gastrointestinal tract (GIT). The high stability of their intrinsic protein structure, dominated by a well-conserved skeleton of cysteine residues, to the harsh conditions present in the GIT suggests that these proteins are able to cross the gut mucosal barrier to sensitize the mucosal immune system and/or elicit an allergic response. The flexible and solvent-exposed hypervariable region of these proteins is immunodominant and has the ability to bind IgE from allergic patients sera. Several linear IgE-binding epitopes of 2S albumins spanning this region have been described to play a major role in allergenicity; the role of conformational epitopes of these proteins in food allergy is far from being understood and need to be investigated. Finally, the interaction of these proteins with other components of the food matrix might influence the absorption rates of immunologically reactive 2S albumins but also in their immune response.

No MeSH data available.


Related in: MedlinePlus