Dissipative Non-Equilibrium Self-Assembly of Cyclic Peptide Nanotubes

Virtual poster session: @ChemSci_IISERK; #chemsci2020poster

Cyclic peptides (CPs) are widely present in nature and are of interest in synthetic systems because of their unique structure. CPs composed of alternating D- and L-amino acids are planar and stack into tubular structures—cyclic peptide nanotubes (CPNs). CPNs are extremely robust and stable due to cooperative H-bonds, electrostatic and hydrophobic interactions that are favorable between the planar rings; they are known to be extremely difficult to disassemble. Developing a reaction cycle can lead to on-demand formation of CPNs and, therefore, facilitate their application as materials and pharmaceuticals. Here we show a chemically fueled reaction cycle that reversibly ligates amines and thiols of peptide fragments, which leads to CPs, followed by formation of CPNs for a predetermined time. In the end, the CPNs are reverted to the original peptide fragments. Our work shows a pathway toward out-of-equilibrium transient CPs which could be of use in biomaterials or in more complex reaction networks.