Structural basis of use of ion flow across the bacterial inner membrane to power secretion and motility

Bacteria need to control import/export of charged molecules across their relatively impermeable membrane(s) which also house many nano-machines critical for motility and hence infection. These processes are often driven by harvesting the energy stored in ion gradients across the inner-membrane by ion flow through inner-membrane resident channels. Unpublished work from my group has demonstrated that bacterial inner-membrane ion channels which couple ion flow to protein secretion, nutrient import and bacterial motility unexpectedly share a common architecture within their membrane domains. The architecture revealed unexpectedly suggests rotation between components may be mechanistically important and this application seeks to test this hypothesis. The question will be assessed by a series of structural and mechanistic studies that will seek to determine what commonalities in mechanism underlie this shared architecture and how this is adapted to perform the very different biologies achieved. Specifically, what adaptations allow coupling of uni-directional ion flow to achieve work on both sides of the inner-membrane. Using structural and functional tools developed in my group we will study the ion channels in more native contexts both in terms of the membrane bilayer and in terms of the protein interactions that couple ion flow to work to tease out molecular mechanisms.