The antibacterial toxin colicin N binds to the inner core of lipopolysaccharide and close to its translocator protein.
Bottom Line: Delipidated LPS (LPS(Δ) (LIPID) ) shows weaker binding; and thus full affinity requires the lipid component.The site of LPS binding means that ColN will preferably bind at the interface and thus position itself close to the surface of its translocon component, OmpF.ColN is, currently, unique among colicins in requiring LPS and, combined with previous data, this implies that the ColN translocon is distinct from those of other known colicins.
Affiliation: Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK.Show MeSH
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Mentions: We used high‐resolution, solid‐state 31P MAS‐NMR to investigate sites of natural phosphorylation and pyrophosphorylation in Rc and Rd LPS and to follow changes in 31P dynamics following addition of ColN‐R. The data were collected in a membrane environment by incorporating Rc LPS (Fig. 5A) and Rd LPS (Fig. 5B) in DOPC membranes (dominant resonance at −1.09 ppm). Phosphate resonances at −0.2 and −0.5 ppm were attributed to Rd LPS, as these were common to both Rc and Rd LPS spectra. These correspond to the single phosphate groups shown in Fig. 5C. The Rc LPS spectra reveal additional phosphorylation sites between −3 and 1 ppm (0.5, −0.2 and −2.3 ppm). Since these are unique to Rc LPS and are absent from Rd LPS, it suggests that pyranose sites on Glc‐(Hep‐II)‐Hep‐GlcN, are available for phosphorylation (Fig. 5C).
Affiliation: Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK.