Researchers engineered an 'autocyclase' protein that performs a controllable self-cyclisation reaction, efficiently producing cyclic peptides and proteins for drug discovery.
High-yield unimolecular cyclisationThe autocyclase performs a controllable self-reaction, eliminating the need for separate enzymes and avoiding concentration-dependent efficiency issues of bimolecular cyclisation methods.
What the researchers found
The researchers engineered a self-cyclising 'autocyclase' protein that performs a unimolecular (single-molecule) head-to-tail macrocyclisation reaction. This approach is fundamentally different from existing enzyme-catalysed methods because it is a controllable self-reaction rather than requiring a separate enzyme to act on the substrate. The autocyclase produced cyclic peptides and proteins in high yield, and the unimolecular reaction mechanism addresses existing challenges in enzymatic cyclisation, such as substrate competition and concentration-dependent efficiency.
Why it matters
Cyclic peptides are among the most promising drug candidates in modern pharmaceutical development because their ring structure makes them resistant to degradation and improves their ability to bind targets. However, making cyclic peptides efficiently has been a major bottleneck. This autocyclase platform provides a simpler, more controllable method that could accelerate the production of cyclic peptide drugs and research tools.
How the study worked
The team used protein engineering to design an autocyclase — a protein containing a built-in self-cyclisation domain. They characterised the reaction mechanism and optimised conditions for controllable cyclisation. The method was validated by producing several known cyclic peptides and proteins, including cyclised nanodiscs (cNDs) used for studying membrane receptors.
What this study cannot tell us
The abstract does not provide specific yield percentages or direct comparisons to existing cyclisation methods, making it difficult to quantitatively assess the advantage over current approaches. The range of peptide/protein sizes and sequences compatible with the autocyclase system is not fully characterised from the abstract alone. Scale-up feasibility for industrial production is also not addressed.
How to read the evidence
This is a methods/technology development paper demonstrating proof-of-concept for a new biochemical engineering approach. While the science is rigorous, it is an early-stage platform technology, not a clinical study.
When this study was published
Published in 2023, this represents a recent advance in the rapidly evolving field of peptide macrocyclisation technology.
The bigger picture
Cyclic peptides occupy a sweet spot in drug discovery — they're larger than small-molecule drugs (allowing them to target difficult protein-protein interactions) but more stable than linear peptides. The market for cyclic peptide therapeutics is growing, and efficient production methods are a key enabler. This autocyclase technology joins other recent advances like split-intein cyclisation and sortase-mediated ligation in expanding the toolkit for cyclic biomolecule production.
Questions still open
- What is the size range of peptides and proteins that can be effectively cyclised using this autocyclase approach?
- How does the yield and cost compare to established enzymatic cyclisation methods like sortase or butelase?
- Can this platform be adapted for high-throughput production of cyclic peptide libraries for drug screening?
Common questions
What are cyclic peptides and why are they important for drug development?
How is this method different from existing ways to make cyclic peptides?
Read the original research
Self-cyclisation as a general and efficient platform for peptide and protein macrocyclisation.
Communications chemistry, 6(1), 48
Citation
Jia, Xinying; Chin, Yanni K-Y; Zhang, Alan H; Crawford, Theo; Zhu, Yifei; Fletcher, Nicholas L; Zhou, Zihan; Hamilton, Brett R; Stroet, Martin; Thurecht, Kristofer J; Mobli, Mehdi. (2023). Self-cyclisation as a general and efficient platform for peptide and protein macrocyclisation.. Communications chemistry, 6(1), 48. https://doi.org/10.1038/s42004-023-00841-5