1H NMR structure of an antifungal γ‐thionin protein SIα1: Similarity to scorpion toxins

The three‐dimensional structure of the Sorghum bicolor seed protein γ‐thionin SIα1 has been determined by 2D 1H nuclear magnetic resonance (NMR) spectroscopy. The secondary structure of this 47‐residue antifungal protein with four disulphide bridges consists of a three‐stranded antiparallel sheet and one helix. The helix is tethered to the sheet by two disulphide bridges which link two successive turns of the helix to alternate residues i, i + 2 in one strand. Possible binding sites for antifungal activity are discussed. The same fold has been observed previously in several scorpion toxins. Proteins 32:334–349, 1998. © 1998 Wiley‐Liss, Inc.

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