Title: Single-Molecule Fluorescence Imaging to Determine the Stoichiometry of the Twin-Arginine Translocase
Abstract: The twin-arginine translocation (Tat) machinery transports folded substrate proteins across the cytoplasmic membrane of bacteria and the thylakoid membrane of chloroplasts. This mechanistically challenging machinery deploys three essential proteins, TatA, TatB, and TatC. TatA is known to form the protein translocating element of the Tat system. The size and the stoichiometry of the Tat translocation complex are thought to be dependent on the size of the substrate. Current models for Tat transport only predict the oligomeric state of TatA and if, and whether, this state changes during the transport cycle. We use single-molecule fluorescence techniques to probe into the stoichiometry of the translocase.