Shen, Y., et al. Potentides: Novel Cysteine-Rich Peptides with Unusual Disulfide Connectivity from Potentilla anserina. ChemBioChem. 10.1002/cbic.201900127. 30/3/2019.
Cysteine-rich peptides (CRPs), disulfide-constrained peptides with three to five disulfide bonds and molecular weights of 2 to 6 kDa, are generally hyperstable and resistant to thermal, chemical and enzymatic degradation. Here, the discovery and characterization of a novel suite of CRPs, collectively named potentides pA1- pA16 from the root of the medicinal herb Potentilla anserina L, are described. Using a combination of proteomic and transcriptomic methods, we showed that 35-residue potentide pA3, the most abundant member of potentides, exhibits high stability against heat, acidic and proteolytic degradation. Transcriptomic analysis revealed that potentide precursor sequences contain four tandem repeats for mature domain, which is the first report that the tandem repeats are found in the Rosaceae family. Disulfide mapping showed that potentide pA3 displays a novel disulfide connectivity of C1-C3, C2-C6 and C4-C5, a cystine motif that has not been reported in plant CRPs. Transcriptomic data mining and a neighbor-joining clustering analysis revealed 56 potentide homologs and their distribution in the families of Rosaceae and Ranunculaceae in angiosperm. Altogether, these results reveal a new plant CRP structure with an unusual cystine connectivity. Additionally, this study expands the families and structure diversity of CRPs as potentially active peptide pharmaceuticals.