Suppression of phospholipid biosynthesis by cerulenin in the condensed Single-Protein-Production (cSPP) system
Using the single-protein-production (SPP) system, a protein of interest can be exclusively produced in high yield from its ACA-less gene in Escherichia coli expressing MazF, an ACA-specific mRNA interferase. It is thus feasible to study a membrane protein by solid-state NMR (SSNMR) directly in natural membrane fractions. In developing isotope-enrichment methods, we observed that 13C was also incorporated into phospholipids, generating spurious signals in SSNMR spectra. Notable, with the SPP system a protein can be produced in total absence of cell growth caused by antibiotics. Here, we demonstrate that cerulenin, an inhibitor of phospholipid biosynthesis, can suppress isotope incorporation in the lipids without affecting membrane protein yield in the SPP system. SSNMR analysis of ATP synthase subunit c, an E. coli inner membrane protein, produced by the SPP method using cerulenin revealed that 13C resonance signals from phospholipid were markedly reduced, while signals for the isotope-enriched protein were clearly present.
KeywordscSPP Membrane protein Phospholipid biosynthesis Cerulenin SSNMR
This work is partially supported by a research funding from Takara Bio. and the National Institutes of Health Grants U54GM75026 (New York Consortium on Membrane Protein Structure) (to A.E.M., G.T.M. and M.I.) and 1R01GM085449 (to M.I.).
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