Crystal structure of a-hordothionin at 1.9 Aresolution

Crystal structure of ubiquitous toxin from barley a- hordothionin (a-HT) has been determined at 1.9 Aresolution by X-ray crystallography. The primary sequence as well as the NMR solution structure of a-HT firmly established that a-HT belongs to a family of membrane active plant toxins-thionins. Since a-HT crystallized in a space group (P41212) that is differ- ent from the space group (I422) of previously determined a1- and b-purothionins, and visocotoxin A3, therefore, it provided inde- pendent information on protein-protein interactions that may be relevant to the toxin mechanism. The structure of a-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. � 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.