Resurrecting the carboxyl polyether ionophores
The carboxyl polyether ionophores (CPIs) is a class of >150 complex natural products. Belonging to the most complicated of Nature's secondary metabolites, they are darlings within total chemical synthesis, however, the biological role of these agents is obscure. Due to their canonical function of equilibrating ion-gradients across biological membranes, CPIs are thought to be unspecific and largely uninteresting. Here, I will advocate and demonstrate the opposite position: that not only are these compounds extremely interesting with respect to their complex effects on cells, they also harbor a unique anti-microbial activity that should be a strong priority as we stagger towards a post-antibiotic era.    With RECYPION my team and I will draw these compounds back into the spotlight. We will ask the following fundamental questions: 1. Can we develop a synthesis-paradigm that will significantly expand the CPI-chemical space to fully explore their anti-microbial activities? 2. What are the molecular determinants that control the antibiotic-potential of the CPIs, and how do these relate to the mechanism of ion-transport? 3. Can we uncover the cellular activities of CPIs – perhaps even “dark” activities that do not involve ion-transport?        We will pioneer a CPI-synthesis-approach based on the ability to recycle complex components from highly abundant CPI-family members. To do so, we will develop novel chemical transformations to deconstruct these molecules which may find broader use in a world that is increasingly focused on how to preserve resources. We will provide the first real experimental characterization of the molecular mechanism by which CPIs mediate ion transport by using ultrafast surface-sensitive spectroscopy on membrane-resident CPIs along with unprecedented structural insight using ultra-high field NMR. Finally, we will use an image-based screening technology called morphological profiling to reveal completely new cellular activities of the CPIs.