Dataset Information

Ginsentides: Cysteine and Glycine-rich Peptides from the Ginseng Family with Unusual Disulfide Connectivity.

ABSTRACT: Ginseng, a popular and valuable traditional medicine, has been used for centuries to maintain health and treat disease. Here we report the discovery and characterization of ginsentides, a novel family of cysteine and glycine-rich peptides derived from the three most widely-used ginseng species: Panax ginseng, Panax quinquefolius, and Panax notoginseng. Using proteomic and transcriptomic methods, we identified 14 ginsentides, TP1-TP14 which consist of 31-33 amino acids and whose expression profiles are species- and tissues-dependent. Ginsentides have an eight-cysteine motif typical of the eight-cysteine-hevein-like peptides (8C-HLP) commonly found in medicinal herbs, but lack a chitin-binding domain. Transcriptomic analysis showed that the three-domain biosynthetic precursors of ginsentides differ from known 8C-HLP precursors in architecture and the absence of a C-terminal protein-cargo domain. A database search revealed an additional 50 ginsentide-like precursors from both gymnosperms and angiosperms. Disulfide mapping and structure determination of the ginsentide TP1 revealed a novel disulfide connectivity that differs from the 8C-HLPs. The structure of ginsentide TP1 is highly compact, with the N- and C-termini topologically fixed by disulfide bonds to form a pseudocyclic structure that confers resistance to heat, proteolysis, and acid and serum-mediated degradation. Together, our results expand the chemical space of natural products found in ginseng and highlight the occurrence, distribution, disulfide connectivity, and precursor architectures of cysteine- and glycine-rich ginsentides as a class of novel non-chitin-binding, non-cargo-carrying 8C-HLPs.

SUBMITTER: Tam JP

PROVIDER: S-EPMC6212409 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

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Ginsentides: Cysteine and Glycine-rich Peptides from the Ginseng Family with Unusual Disulfide Connectivity.

Tam James P JP Nguyen Giang K T GKT Loo Shining S Wang Shujing S Yang Daiwen D Kam Antony A

Scientific reports 20181101 1

Ginseng, a popular and valuable traditional medicine, has been used for centuries to maintain health and treat disease. Here we report the discovery and characterization of ginsentides, a novel family of cysteine and glycine-rich peptides derived from the three most widely-used ginseng species: Panax ginseng, Panax quinquefolius, and Panax notoginseng. Using proteomic and transcriptomic methods, we identified 14 ginsentides, TP1-TP14 which consist of 31-33 amino acids and whose expression profil ...[more]

PMID: 30385768

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Project description:Disulfide bridges in proteins are formed by the oxidation of pairs of cysteine residues. These cross-links play a critical role in stabilizing the 3D-structure of small disulfide rich polypeptides such as hormones and venom toxins. The arrangement of the multiple disulfide bonds directs the peptide fold into distinct structural motifs that have evolved for resistance against biochemical and physical insults. These structural scaffolds have, therefore, proven to be very attractive in bioengineering efforts to develop novel biologics with applications in health and agriculture. Structural characterization of small disulfide rich peptides (DRPs) presents unique challenges when using commonly applied biophysical methods. NMR is the most commonly used method for studying such molecules, where the relatively small size of these molecules results in highly precise structural ensembles defined by a large number of distance and dihedral angle restraints per amino acid. However, in NMR the sulfur atoms that are involved in three of the five dihedral angles in a disulfide bond cannot be readily measured. Given the central role of disulfide bonds in the structure of these molecules, it is unclear what the inherent resolution of such NMR structures is when using traditional NMR methods. Here, we use an extensive set of long-range residual dipolar couplings (RDCs) to assess the resolution of the NMR structure of a disulfide-rich peptide. We find that structures based primarily on NOEs, yield ensembles that are equivalent to a crystallographic resolution of 2-3 Å in resolution, and that incorporation of RDCs reduces this to ~1-1.5 Å resolution. At this resolution the sidechain of ordered amino acids can be defined accurately, allowing the geometry of the cysteine bridges to be better defined, and allowing for disulfide-bond connectivities to be determined with high confidence. The observed improvements in resolution when using RDCs is remarkable considering the small size of these peptides.

Dataset Information

Ginsentides: Cysteine and Glycine-rich Peptides from the Ginseng Family with Unusual Disulfide Connectivity.

Publications

Ginsentides: Cysteine and Glycine-rich Peptides from the Ginseng Family with Unusual Disulfide Connectivity.

Similar Datasets

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