A Synthetic Molecular Machine Capable of Complex Task Performance

This research mimics translation, the process through which protein is synthesized on the mRNA template in the ribosome. [2]rotaxane acts as both a catalyst and a molecular transporter, abstracting bulky aromatic amino acid substituents from a sequence-specific ‘thread’ and transporting them in turn to the next amino acid fragment before mediating the formation of a newa amide bond between them. The design is such that the macrocycle is forced to approach each amino acid in sequence, and is unable to pass until the cycle is complete, imparting sequential integrity to the oligopeptide synthesis. The mechanically interlocked nature of the rotaxane ensures processivity during the machine’s operation. Although biology uses threaded molecular architectures to transfer chemical information during sequence-specific oligomer and polymer assembly (proteins, oligo- and polysaccharides, DNA and RNA), such effects are unprecedented in artificial systems.