Different Structural Behaviors Evidenced in Thaumatin-Like Proteins: A Spectroscopic Study

Abstract

Three proteins belonging to the thaumatin-like proteins family were compared in this study from a structural point of view: zeamatin, a new recently isolated PR-5 from Cassia didymobotrya and the commercial sweet-thaumatin. The former two proteins possess antifungal activities while commercial thaumatin is well known to be a natural sweetener. Intrinsic fluorescence studies have evidenced that the three proteins behave differently in unfolding experiments showing different structural rigidity. All the three proteins are more stable at slight acidic buffers, but sweet-thaumatin has a major tendency to destructurate itself. Similar observations were made from circular dichroism studies where a structural dependence relationship from the pH and the solvent used confirmed a hierarchic scale of stability for the three proteins. These structural differences should be considered to be significant for a functional role.

Characterization of peach thaumatin‐like proteins and their identification as major peach allergens

“…TLPs are proteins with a molecular weight of 20–30 kDa, and a very compact three‐dimensional (3D) structure maintained by eight disulphide bridges [10, 20]. This highly conserved 3D folding helps their resistance to the process of digestion in the gut and heat treatments at acidic pHs [21, 22].…”

“…This protein family is comprised of plant defence proteins (pathogenesis‐related protein; PR5) (especially against fungal attacks). There are two types of TLPs, differing with respect to their cellular location: acidic, which are directly driven to the apoplastic space, and basic, which are transported to the vacuole and ejected from the cell under some stress conditions [20].…”

Exercise induced anaphylaxis in kiwi allergic patient: case report

“…TLPs are characterized by a resistance against digestion in the digestive tract and are insensitive to acids and high temperature. They are also present in food after cooking or industrial processing [23,24].…”

A preliminary neutron crystallographic study of thaumatin

“…This neutron diffraction study aims towards the design of new sweetners and a better understanding of the mechanism of taste by providing information that can help characterize active sites in the protein under different pH conditions. Furthermore, we expect the neutron crystallography results to shed light onto the effect of pH on the structural stability of TLPs (Perri et al, 2008).…”