Characterizing Bacterial Cell Wall Synthesis Through the Use of Fluorescent Stem Peptide Mimics

Abstract This project focused on developing fluorescent probes to characterize cell wall biosynthesis in a variety of bacterial species. The overall goal of this work was to develop a library of fluorescently-conjugated molecules that mimic the naturally occurring stem peptides of bacteria which could be used to study crosslinking in vivo. By building an assortment of tetrapeptides and pentapeptides, we were able to develop molecules which could be used monitor Ldt activity in vivo. Furthermore, by synthesizing similar molecules with slight variations, we were able to determine that amidation of key sites can play a major role in dictating biosynthetic activity. Lastly, an ongoing project involved the synthesis of a cystine-based stem peptide which mimics mDAP at the third position, allowing for more accurate study of the biosynthetic pathways in the large class of bacteria which contain this non-canonical amino acid in their peptidoglycan.