Controlling macromolecular conformation for the nanoscale transmission of information

Abstract

Helical oligomers made up of the achiral amino acid Aib (2-aminoisobutyric acid) have great potential in relaying stereochemical information over nanometre distances by control of their macromolecular conformation. In a synthetic signalling pathway, the helical domain acts as a transducer, mediating the information flow between an input and an output. This thesis describes the advancement of these helical systems into functioning, dynamic transduction pathways capable of nanoscale information processing by a variety of different means.Through studying the effect of C-terminal chiral amino acids, alanine was found to give maximal control over the helical screw-sense. It was also discovered that the hydrogen bonding preference of the terminal group (ester, amide etc.) determined the screw-sense direction. By modifying the terminus, this directional preference was inverted using light or pH as secondary stimuli.Non-covalent interactions with solvent were found to be important in controlling the flow of information through the helical domain. In less polar solvents (THF, chloroform) a single screw sense can prevail for up to 200 monomers, leading to very low signal loss.A zinc binding site was developed to allow a chiral ligand to act as the input in the signalling process. Both amino and phosphoric acids led to remarkable levels of screw-sense induction. Using the reversible ligand binding interaction a pH switch was set up to moderate the binding of these two ligands, creating a ternary information switch. Significant progress was also made towards a light switch using a spiropyran as a competing ligand.Finally, a novel light-responsive switch capable of releasing a signalling molecule in solution was conceived and developed.

Date of Award	1 Aug 2015
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Jonathan Clayden (Supervisor)