1. A novel antifungal hevein-type peptide from Triticum kiharae seeds with a unique 10-cysteine motif
Tatyana I Odintsova, et al. FEBS J. 2009 Aug;276(15):4266-75. doi: 10.1111/j.1742-4658.2009.07135.x. Epub 2009 Jul 3.
Two forms of a novel antimicrobial peptide (AMP), named WAMP-1a and WAMP-1b, that differ by a single C-terminal amino acid residue and belong to a new structural type of plant AMP were purified from seeds of Triticum kiharae Dorof. et Migusch. Although WAMP-1a and WAMP-1b share similarity with hevein-type peptides, they possess 10 cysteine residues arranged in a unique cysteine motif which is distinct from those described previously for plant AMPs, but is characteristic of the chitin-binding domains of cereal class I chitinases. An unusual substitution of a serine for a glycine residue in the chitin-binding domain was detected for the first time in hevein-like polypeptides. Recombinant WAMP-1a was successfully produced in Escherichia coli. This is the first case of high-yield production of a cysteine-rich plant AMP from a synthetic gene. Assays of recombinant WAMP-1a activity showed that the peptide possessed high broad-spectrum inhibitory activity against diverse chitin-containing and chitin-free pathogens, with IC(50) values in the micromolar range. The discovery of a new type of AMP active against structurally dissimilar microorganisms implies divergent modes of action and discloses the complexity of plant-microbe interactions.
2. Solution structure of a defense peptide from wheat with a 10-cysteine motif
Peter V Dubovskii, Alexander A Vassilevski, Anna A Slavokhotova, Tatyana I Odintsova, Eugene V Grishin, Tsezi A Egorov, Alexander S Arseniev Biochem Biophys Res Commun. 2011 Jul 22;411(1):14-8. doi: 10.1016/j.bbrc.2011.06.058. Epub 2011 Jun 14.
Hevein, a well-studied lectin from the rubber tree Hevea brasiliensis, is the title representative of a broad family of chitin-binding polypeptides. WAMP-1a, a peptide isolated from the wheat Triticum kiharae, shares considerable similarity with hevein. The peptide possesses antifungal, antibacterial activity and is thought to play an important role in the defense system of wheat. Importantly, it features a substitution of the conserved serine residue to glycine reducing its carbohydrate-binding capacity. We used NMR spectroscopy to derive the spatial structure of WAMP-1a in aqueous solution. Notably, the mutation was found to strengthen amphiphilicity of the molecule, associated with its mode of action, an indication of the hevein domain multi-functionality. Both primary and tertiary structure of WAMP-1a suggest its evolutionary origin from the hevein domain of plant chitinases.
