Novel antifungal α-hairpinin peptide from Stellaria media seeds: structure, biosynthesis, gene structure and evolution.
Anna A Slavokhotova, Eugene A Rogozhin, Alexander K Musolyamov, Yaroslav A Andreev, Peter B Oparin, Antonina A Berkut, Alexander A Vassilevski, Tsezi A Egorov, Eugene V Grishin, Tatyana I Odintsova
Author Information
Anna A Slavokhotova: Vavilov Institute of General Genetics, Russian Academy of Sciences, ul. Gubkina 3, 119991, Moscow, Russian Federation, annslav82@gmail.com.
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 (C(1)X3C(2)XnC(3)X3C(4)), 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 C(1)-C(4) and C(2)-C(3). 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.
Associated Data
GENBANK | HG423454
UniProtKB | C0HJD6
References
Protein Expr Purif. 2008 Jul;60(1):89-95
[PMID: 18455432]
Curr Protein Pept Sci. 2005 Feb;6(1):85-101
[PMID: 15638771]
Nucleic Acids Res. 1999 Jan 15;27(2):573-80
[PMID: 9862982]
J Biol Chem. 2000 Feb 18;275(7):5193-9
[PMID: 10671566]
