Protons move through proteins in ways that have never been directly observed—this project aims to watch them for the first time. Proton transfer is central to life: it drives ATP production, the energy currency of cells. But researchers currently can only measure the end result of these reactions, not the specific pathways protons take through proteins. This fundamental gap limits understanding of how enzymes and molecular machines actually work. The team has developed two artificial amino acids—one that releases a proton when hit with light, another that accepts it. By inserting these into precise locations within proteins, they can trigger and track proton movement along defined routes. They plan to test this in ATP synthase (the protein that makes cellular energy) and carbonic anhydrase (an enzyme that regulates pH). This is fundamental science with no immediate practical application. But understanding proton transfer at this level could eventually help design better catalysts, improve artificial photosynthesis, or explain how mutations in proton-transporting proteins cause disease. Similar fundamental work on ion channels and pumps has already led to drugs for cystic fibrosis and heart conditions.
View original technical description
Proton transfer (PT) reactions within proteins are fundamental in biological systems, such as within ATP production. To date, there are no direct means to measure specific PT pathways within proteins, and most research is based on following the end-product of the PT reaction across a natural proton pathway. Here, our goal is to develop a novel way to directly measure PT within proteins. Our new approach is based on placing proton donors and acceptors in specific places within proteins, in which the PT will be initiated only after light excitation of the system. To do so, we introduce here two noncanonical amino acids (ncAA) we developed, with a photoacid and a photobase as their residues that serve as the proton donor and acceptor, respectively. Our hypothesis is that the strong light-triggered driving force of PT in the excited-state (of ~11 pKa units) will initiate PT along the pathway from donor to acceptor. In the first objective, we will use our new ncAA with solid-phase peptide synthesis to design several peptide systems that will allow us to decipher the role of specific amino acids, the peptide structure, and the role of water in PT across the peptide using various ultrafast spectroscopy. In the second objective, we aim to design a mutually orthogonal system for the insertion of our two ncAA into a single protein. In our third objective, we plan to use our new experimental system for answering a unique set of questions in the field of biological PT that could not have been answered before, focusing on the systems of ATP synthase transmembrane complex and the soluble carbonic anhydrase enzyme. Our new approach is groundbreaking in the way we study and understand PT in biology and will enable researchers completely new capabilities resulting in fascinating new discoveries. Moreover, our new system can be translated into other fields in biology that require the local change in proton concentration within proteins.
Plain English summaries and category classifications on this site are generated by AI and may not perfectly reflect the original research.
Is something wrong? Let us know