Project description

Recent attempts to mimic enzyme catalysis using simple, prebiotically relevant peptides have been successful in enhancing various reactions. However, the on-demand, temporal or spatial regulation of such processes by external triggers remains a great challenge. Light irradiation is an ideal trigger for regulating molecular functionality, since it can be precisely manipulated in time and space, and because most reaction mediums do not react to light. We will study a photo-switchable amphiphilic peptide catalyst from a small library of isomeric peptides, each containing an azobenzene-based light responsive group and a catalytic histidine residue. In its native fibrillar form, the selected peptide is expected to be efficiently and enantio-selectively active for ester hydrolysis. However after irradiation by UV light inducing trans-to-cis azobenzene isomerization, the fibrils disassemble to amorphous aggregates that are much less catalytically active. Significantly, we will study that this esterase-like activity can be manipulated multiple times, as the fibrillar peptide assembly will be reversibly reduced and restored upon alternate irradiation by UV and visible light, respectively. We propose that this research may shine light on the origin of complex functions in early chemical evolution. Furthermore, it paves the way to regulate additional functions for peptide nanotechnology, such as replication, charge transfer, and delivery.

Additional specifications

We look for a candidate with a MSc in (Physical organic or Organic) Chemistry or Molecular Life Sciences or a related discipline. Experience with technique peptide synthesis, catalysis and self-assembly is recommended. This project will entail both peptide design and synthesis, biophysical characterization using several techniques and catalysis.