Pollen allergen Amb t 5 (UniProt: P10414; also known as Allergen Amb t V, Allergen Ra5G, Amb t 5) binds to IgE and causes allergic reaction in human. Inntag IT10 is a small protein domain of Ambrosia trifida (Giant ragweed) that displays strong structural determinants and does not generate solubility issues in vivo and in vitro. Also, it does not compromise cell fitness when overexpressed, and has no detectable functional and localization effects when fused to a variety of target proteins. Structure of the Inntag IT10 is based on a packed beta-sheet conformation.