Nature has developed molecular machines to rapidly assemble, modify, and deliver proteins into cells. Inspired by these mechanisms, the Pentelute Lab explores new cysteine and lysine arylation chemistries for the efficient and selective modification of proteins, employs chemical biology to systematically dissect how anthrax toxin hijacks biomolecules into cells, and develops fast flow platforms for the rapid production of peptides and other chemically modified biomolecules. We aim to invent new chemistry to modify Nature’s proteins to enhance their therapeutic properties for human medicine. This new chemistry needs to be protein compatible, site-selective, quantitative, and carried out in water at reasonable temperatures to maintain protein integrity and function. The Pentelute Lab has met these challenges and has developed a series of highly efficient and selective methodologies that can modify cysteine and lysine side chains within peptides and proteins. These reactions can be catalyzed by enzymes or even promoted by a motif discovered by our group, coined a ‘pi-clamp’. This extensive protein modification toolkit has enabled the production of potent molecules, including peptide macrocycles that cross cell membranes and the blood-brain barrier to disrupt cancer or antibody-drug conjugates to kill breast cancer cells.

We are also focused on the delivery of large biomolecules into the cell cytosol and nucleus. The group has developed a chemical approach for the systematic investigation of a nontoxic form of anthrax toxin, which transports enzymes into cells via a protective antigen-protein pump. This pump can deliver a wide range of cargo molecules including antibody mimics, mirror-image proteins, small molecules, and enzymes. Once in the cytosol, the cargo activates biologically and in certain cases perturbs protein-protein interactions that drive cancer. Noteworthy, we discovered that by simply installing a single D-amino acid on a large L-protein turns off a key mechanism for cytosolic protein degradation. This discovery will aid in the development of durable cell-based protein therapeutics. In parallel, we are actively investigating delivery of therapeutic antisense oligonucleotides to the cell nucleus with cell-penetrating peptides, a large collection of chemical vectors abundant in Nature.

We have invented a fully automated fast-flow machine to accelerate the chemical manufacture of polypeptides. The Pentelute Lab has built the world’s fastest and most efficient peptide synthesizer that can produce amide bonds orders of magnitude faster than commercially available instruments. The machine is inspired by Nature’s ribosome that can incorporate 9 amino acids into a polypeptide chain per second. While our technology is not as fast as the ribosome, it can form one amide bond in 10 seconds or less. This technology not only facilitates rapid polypeptide and even small protein generation, but it has enabled the group to carry out entire D-scans of proteins to investigate their folding and functions. This technology may solve the manufacturing problem for personalized peptide-based cancer vaccines, a challenge we are currently tackling.