Crystal structure of α-hordothionin at 1.9 Å resolution

Crystal structure of ubiquitous toxin from barley α-hordothionin (α-HT) has been determined at 1.9 Å resolution by X-ray crystallography. The primary sequence as well as the NMR solution structure of α-HT firmly established that α-HT belongs to a family of membrane active plant toxins–thionins. Since α-HT crystallized in a space group (P41212) that is different from the space group (I422) of previously determined α1- and β-purothionins, and visocotoxin A3, therefore, it provided independent information on protein–protein interactions that may be relevant to the toxin mechanism. The structure of α-HT not only confirms overall architectural features (crambin fold) but also provides an additional confirmation of the role for crucial solute molecules, that were postulated to be directly involved in the mechanism of toxicity for thionins.