Discovery of Cyclotides: A New Family of Ultra-Stable Circular Peptides From Plants
Sixteen new cyclotides were discovered in plants, establishing a unique peptide family with exceptional stability from their circular backbone and knotted disulfide bonds, with potential antimicrobial and anti-HIV applications.
Quick Facts
What This Study Found
Sixteen novel cyclotides were identified from three plant species, all sharing the cyclic cystine knot motif that confers exceptional thermal, chemical, and enzymatic stability, with diverse bioactivities including antimicrobial and anti-HIV effects.
Key Numbers
How They Did This
In-vitro study using extraction, HPLC purification, mass spectrometry, and NMR structural characterization to identify and characterize cyclotides from Viola hederaceae, Viola odorata, and Oldenlandia affinis plant extracts.
Why This Research Matters
Cyclotides' extraordinary stability solves one of the biggest problems in peptide drug development — most peptides are quickly destroyed in the body. Their circular, knotted structure could serve as a template for designing stable oral peptide drugs.
The Bigger Picture
Traditional peptide drugs break down quickly in the body. Cyclotides show that nature has already solved this stability problem. By grafting drug-like sequences into the cyclotide framework, researchers could create an entirely new class of stable oral peptide medicines.
What This Study Doesn't Tell Us
Discovery and structural characterization study. Bioactivities described are primarily from initial screening. Detailed mechanism of action and therapeutic potential require further study.
Questions This Raises
- ?Can cyclotides be used as drug scaffolds for oral peptide therapeutics?
- ?What is the mechanism behind cyclotide anti-HIV activity?
- ?Can cyclotides be produced economically by chemical synthesis or bioengineering?
Trust & Context
- Key Stat:
- 16 new peptides Dramatically expanded the known cyclotide family, all sharing the ultra-stable cyclic cystine knot structure
- Evidence Grade:
- Moderate evidence from a comprehensive discovery study with structural characterization and initial bioactivity screening of a novel peptide family.
- Study Age:
- Published in 1999. Cyclotide research has grown enormously since, with cyclotide drug scaffolds now in preclinical development for various diseases.
- Original Title:
- Plant cyclotides: A unique family of cyclic and knotted proteins that defines the cyclic cystine knot structural motif.
- Published In:
- Journal of molecular biology, 294(5), 1327-36 (1999)
- Authors:
- Craik, D J(3), Daly, N L(3), Bond, T, Waine, C
- Database ID:
- RPEP-00518
Evidence Hierarchy
Frequently Asked Questions
What makes cyclotides special?
Unlike most peptides that break down in minutes, cyclotides have a circular backbone with interlocking disulfide bonds that make them incredibly stable against heat, acid, and digestive enzymes — potentially enabling oral peptide drugs.
Could these become medicines?
Yes. Researchers are using cyclotides as stable scaffolds by inserting drug sequences into their framework. This could create oral peptide drugs for conditions currently requiring injections.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-00518APA
Craik, D J; Daly, N L; Bond, T; Waine, C. (1999). Plant cyclotides: A unique family of cyclic and knotted proteins that defines the cyclic cystine knot structural motif.. Journal of molecular biology, 294(5), 1327-36.
MLA
Craik, D J, et al. "Plant cyclotides: A unique family of cyclic and knotted proteins that defines the cyclic cystine knot structural motif.." Journal of molecular biology, 1999.
RethinkPeptides
RethinkPeptides Research Database. "Plant cyclotides: A unique family of cyclic and knotted prot..." RPEP-00518. Retrieved from https://rethinkpeptides.com/research/craik-1999-plant-cyclotides-a-unique
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.