Molecular Systems Architecture: From Complexity to Function

Nature employs self-assembly the bringing together of molecular sub-units under thermodynamic control, during which less-stable assemblies are broken up in favour of the most stable assemblies to construct her most complex architectures, from the folds and adhesions that lend tertiary and quaternary structure to proteins, to the zipping-up of DNA. Within living organisms many different self-assembly processes are continuously occurring in parallel. These processes use many of the same interactions (such as hydrogen bonding, Coulombic attraction or repulsion, or hydrophobic effects) in similar ways, yet these parallel self-assembly processes are able to avoid interfering with each other. One strand of our research programme seeks to decipher the complex rule sets followed by abiological building blocks as they self-assemble within systems. Once understood, these rule sets may be used to create either single complex architectures, in which individual building blocks might at first glance have several possible destinations, but where hierarchies of rules collectively direct the system to produce a single product, or systems of structures that share common building blocks and self-assembly processes, yet which self-assemble without interfering with each other. Systems of the second type may be induced to reassemble in complex ways upon the addition of a single new building block, as the incorporation of this building block causes one structure to rearrange, releasing other building blocks that may induce the rearrangement of other structures within the system. The study of such cascade processes, and the deciphering of complex self-assembly rules more generally, may help shed light upon the underpinnings of biological complexity.