Phosphorus-31 Nuclear Magnetic Resonance Investigation of Membrane Vesicles from Escherichia coli

Phosphorus-31 nuclear magnetic resonance studies of isolated membrane vesicles prepared from Escherichia coli PSM116 as described by Hunt and Hong [Hunt, A. G., & Hong, J.-S. (1981) J. Biol. Chem. 256, 11988–11991; Hunt, A. G., & Hong, J.-S. (1983) Biochemistry 22, 844–850] are detailed here. This strain harbored a recombinant plasmid containing the phosphoglycerate transport system from Salmonella typhimurium (pJH7). Evidence indicating a surprising metabolic diversity, such as the presence of the enzymes enolase and phosphoglycerate mutase, is presented. The nature of the energization of these membrane vesicles for transport as described by Hugenholtz et al. [Hugenholtz, J., Hong, J.-S., & Kaback, H. R. (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 3446–3449] is also discussed. Membrane vesicles prepared from the PSM116 strain do not form a transmembrane pH gradient when phosphoenolpyruvate is added. The present results show that phosphorus-31 nuclear magnetic resonance spectroscopy is an excellent tool to investigate the metabolism of membrane vesicles.