Biogenesis and targeting mechanisms of bacterial proteins is a central process in Microbiology. About one third of the bacterial proteins have to either insert into the membrane or to translocate across the plasma membrane. The mechanisms involved employ many chaperones, insertases and translocases which use sophisticated enzymic activities to fulfill their function. All these components are potential targets for antibiotic effectors. Therefore, a molecular understanding of the structure and thefunctional feature of these components is crucial for the discovery of new antibiotics. In my laboratory we are working on the bacterial signal recognition particle SRP that is responsible to target the newly synthesized proteins to the membrane surface. Also, the SecYEG translocase and the YidCinsertase are studied with physiological, biochemical and single molecule methods. Explicitly, the molecular mechanism how proteins fold into membranes and how proteins are transported across membranes is in the focus of our research.