The outer membrane of E.coli is a useful model system for studying membrane structure and biosynthesis because it is intermediate in complexity between lipid model systems and a typical cell membrane. We have focused on the other membrane lipoprotein since it is one of the most extensively characterized membrane proteins in terms of structure, biosynthesis and genetics. The gene for the lipoprotein (lpp) has been cloned, and the nucleotide sequence of the lpp gene has been determined. We are in a position to combine modern genetic engineering methods with the powerful spectroscopic techniques, nuclear magnetic resonance (NMR) and electron spin resonance (ESR) to study important aspects of membrane structure and membrane assembly. Genetic manipulations will be used to label the protein with magnetic probes such as 13C-tyrosine, 19f-tyrosine, etc. and covalently attached spin labels. Straightforward application of standard NMR and ESR methods will provide structural and dynamic information about the lipoprotein. This information will shed light upon the interactions of the lipoprotein with other membrane proteins, phospolipids, and the peptidoglycan. Spin label ESR experiments will help elucidate the role of membrane fluidity in membrane assembly. The mechanism for secretion of the lipoprotein through the inner membrane can also be investigated by magnetic resonance experiments with use of the new antibiotic, globomycin, which causes the accumulation of the prolipoprotein in the inner membrane. The principal investigators have expertise in NMR, spin label ESR, and genetic manipulations in this system. Published preliminary experiments demonstrate the feasibility of the approaches described.