Published papers

Advances in bioinformatics have enabled the discovery of unique enzymatic reactions, particularly for ribosomally synthesized and post-translationally modified peptides (RiPPs). The recently discovered daptides, peptides with their C-terminus replaced by an amine, represent one such case, but the diversity, requirements, and engineering potential of daptide biosynthesis remain to be established. Using the daptide biosynthetic gene clusters from Thermobifida fusca and Streptomyces azureus, we reconstituted daptide biosynthesis in vitro, revealing the enzymatic requirements for successive oxidative decarboxylation, transamination, and N,N-dimethylation. In vitro and in vivo studies showed a tailoring family of YcaO enzymes convert a secondary amine intermediate to a C-terminal imidazoline. We further demonstrated enzymatic activity toward shortened, leader peptide-free, and non-native core peptides, highlighting a broad substrate tolerance. Using these insights, we directed the daptide pathway to install new C-termini, including a bioconjugation-compatible aminoacetone, on various peptide and protein substrates.

Thousands of highly oxygenated terpenoid natural products contain a common trans-decalin core bearing oxidized substituents in either the equatorial or axial configuration at the C(4) quaternary center. We report an expedient route to a versatile terpenoid building block primed for elaboration into numerous complex natural products. This intermediate is provided from (R)-carvone, a cheap and abundant chiral pool material, in three steps through a diastereodivergent, intramolecular carboborylation reaction. Notably, this method uniquely provides either equatorial or axial functionalized products from a single, common precursor. Identification of optimal ligands required extensive screening efforts, facilitated in part by high-throughput experimentation (HTE) and the construction of an algorithmically guided, combinatorial, in silico library, which identified the highest performing axial-selective ligand. The key interactions responsible for the observed high diastereoselectivity were elucidated with computational analysis, and the synthetic utility of this method was demonstrated in the total synthesis of several diterpenoid natural products.