Novel antifungal α-hairpinin peptide from Stellaria media seeds: structure, biosynthesis, gene structure and evolution
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Plant defense against disease is a complex multistage system involving initial recognition of the invading pathogen, signal transduction and activation of specialized genes. An important role in pathogen deterrence belongs to so-called plant defense peptides, small polypeptide molecules that present antimicrobial properties. Using multidimensional liquid chromatography, we isolated a novel antifungal peptide named Sm-AMP-X (33 residues) from the common chickweed (Stellaria media) seeds. The peptide sequence shows no homology to any previously described proteins. The peculiar cysteine arrangement (C1X3C2XnC3X3C4), however, allocates Sm-AMP-X to the recently acknowledged α-hairpinin family of plant defense peptides that share the helix-loop-helix fold stabilized by two disulfide bridges C1–C4 and C2–C3. Sm-AMP-X exhibits high broad-spectrum activity against fungal phytopathogens. We further showed that the N- and C-terminal “tail” regions of the peptide are important for both its structure and activity. The truncated variants Sm-AMP-X1 with both disulfide bonds preserved and Sm-AMP-X2 with only the internal S–S-bond left were progressively less active against fungi and presented largely disordered structure as opposed to the predominantly helical conformation of the full-length antifungal peptide. cDNA and gene cloning revealed that Sm-AMP-X is processed from a unique multimodular precursor protein that contains as many as 12 tandem repeats of α-hairpinin-like peptides. Structure of the sm-amp-x gene and two related pseudogenes sm-amp-x-ψ1 and sm-amp-x-ψ2 allows tracing the evolutionary scenario that led to generation of such a sophisticated precursor protein. Sm-AMP-X is a new promising candidate for engineering disease resistance in plants.
KeywordsWeeds cDNA cloning Gene structure Plant defense Protein biosynthesis α-hairpinin
We thank Dr. Sergey I. Kovalchuk for peptide synthesis, Kseniya S. Kudryashova for CD measurements and Natalia V. Khadeeva for antibacterial assay. Support from the Russian Foundation for Basic Research [Grants 12-04-00117a and 11-04-00190a], the Biodiversity Program and the Program of Molecular and Cell Biology of the Russian Academy of Sciences is acknowledged. AAS and AAV are recipients of the stipend of the President of Russian Federation.
- Nolde SB, Vassilevski AA, Rogozhin EA, Barinov NA, Balashova TA, Samsonova OV, Baranov YV, Feofanov AV, Egorov TA, Arseniev AS, Grishin EV (2011) Disulfide-stabilized helical hairpin structure and activity of a novel antifungal peptide EcAMP1 from seeds of barnyard grass (Echinochloa crus-galli). J Biol Chem 286(28):25145–25153PubMedCrossRefGoogle Scholar
- Odintsova TI, Vassilevski AA, Slavokhotova AA, Musolyamov AK, Finkina EI, Khadeeva NV, Rogozhin EA, Korostyleva TV, Pukhalsky VA, Grishin EV, Egorov TA (2009) A novel antifungal hevein-type peptide from Triticum kiharae seeds with a unique 10-cysteine motif. FEBS J 276(15):4266–4275PubMedCrossRefGoogle Scholar
- Tailor RH, Acland DP, Attenborough S, Cammue BP, Evans IJ, Osborn RW, Ray JA, Rees SB, Broekaert WF (1997) A novel family of small cysteine-rich antimicrobial peptides from seed of Impatiens balsamina is derived from a single precursor protein. J Biol Chem 272(39):24480–24487PubMedCrossRefGoogle Scholar
- Utkina LL, Andreev YA, Rogozhin EA, Korostyleva TV, Slavokhotova AA, Oparin PB, Vassilevski AA, Grishin EV, Egorov TA, Odintsova TI (2013) Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence. FEBS J 280(15):3594–3608PubMedCrossRefGoogle Scholar