Presentation description

Natural products synthesized through ribosomally synthesized and post-translationally modified peptides (RiPPs) exhibit diverse arrays of biological activities. To enhance these peptides, S-adenosyl-L-methionine (SAM) and iron-sulfur (4Fe-4S) clusters are used as cofactors to create a radical known as rSAM to induce novel RiPP modifications. This project explores "Lego-proteins", which combine the rSAM maturase of PapB's catalytic domain with the RiPP recognition element (RRE) of a separate system. This creates hybrid enzymes that can perform unique peptide alterations such as thioether crosslinks between cysteine and aspartic acid. These rSAM enzymes are produced in E. coli, taken through anaerobic protein purification, and tested with synthetic peptides. High-resolution mass spectrometry (MS) is used to determine whether non-native crosslinking happened in the modified peptides. This study can further advance the field of synthetic biology and expand natural product biosynthesis applications in drug development and biotechnology.