allergenic/antifungal thaumatin-like proteins: plant and animal homologs
This subfamily is represented by the thaumatin-like proteins (TLPs), Cherry Allergen Pru Av 2 TLP, Peach PpAZ44 TLP (a propylene-induced TLP in abscission), the Caenorhabditis elegans thaumatin family member (thn-6), and other plant and animal homologs. TLPs are involved in host defense and a wide range of developmental processes in fungi, plants, and animals. Due to their inducible expression by environmental stresses such as pathogen/pest attack, drought and cold, plant TLPs are classified as the pathogenesis-related (PR) protein family 5 (PR5). Several members of the plant TLP family have been reported as food allergens from fruits (i.e., cherry, Pru av 2; bell pepper, Cap a1; tomatoes, Lyc e NP24) and pollen allergens from conifers (i.e., mountain cedar, Jun a 3; Arizona cypress, Cup a3; Japanese cedar, Cry j3). TLPs are three-domain, crescent-fold structures with either an electronegative, electropositive, or neutral cleft occurring between domains I and II. It has been proposed that the antifungal activity of plant PR5 proteins relies on the strong electronegative character of this cleft. Some TLPs hydrolyze the beta-1,3-glucans of the type commonly found in fungal walls. TLPs within this subfamily contain 16 conserved Cys residues.
Comment:Thaumatin-like proteins are crescent-fold structures with either an electronegative, electropositive, or neutral cleft occurring between domains I and II.
Comment:It has been proposed that the antifungal activity of plant PR5 proteins (pathogenesis-related protein family 5) relies on the strong electronegative character of the cleft with conserved cleft residues: Arg, Glu, Asp, Asp, and Asp.
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