The Development of Receptors and Chemosensors for the Recognition of Proximally Phosphorylated Motifs

Protein phosphorylation is an important post-translational modification central to controlling protein activity and function. While single residue phosphorylation is common, di- or poly- phosphorylation on proximal residues has emerged as a functionally significant motif often implicated in certain diseased states. Despite the relevance of these motifs, there has been limited effort towards the development of tools to target this type of phosphosite. To advance the understanding of this field, a metal-based triethylbenzene receptor was developed with the goal of selectively targeting proximally phosphorylated motifs over mono-phosphorylated motifs on peptides. While this receptor scaffold was not sufficiently suitable for this aim, it was successfully applied towards the recognition of small molecule phosphoanions ATP and PPi and was used for their selective sequestration in a phosphopeptide detection assay. The conclusion of these findings prompted a change in the initial receptor-based recognition strategy of di-phosphorylated motifs, which resulted in the development of a lanthanide-based chemosensing approach. Tb3+ luminescence was used for the selective detection of a specific subset of proximally phosphorylated peptide motifs over mono-phosphorylated peptides and off-target phosphoanions. This chemosensing strategy has the potential to be applied as a high-throughput screening tool for different subsets of the phosphoproteome and could be of significant value in elucidating diseased states.Ph.D