Average thickness of cytoplasmic (inner) membrane

Value 37.5 Å Range: ±0.5 Å
Organism Bacteria Escherichia coli
Reference Mitra K, Ubarretxena-Belandia I, Taguchi T, Warren G, Engelman DM. Modulation of the bilayer thickness of exocytic pathway membranes by membrane proteins rather than cholesterol. Proc Natl Acad Sci U S A. 2004 Mar 23 101(12):4083-8 doi: 10.1073/pnas.0307332101 p.4087 left columnPubMed ID15016920
Method Solution x-ray scattering (SXS). P.4085 left column bottom paragraph: "SXS permits direct determination of the distance (d) between the highly electron-dense phosphate groups across the bilayer of membranes in solution (refs 14, 15, 17). A limitation of this technique is that extramembranous protein domains and cell components containing highly electron-dense groups, such as ribosomes, can affect the quality of the scattering data (ref 37)."
Comments P.4087 left column: "[Investigators] wanted to establish the generality of this effect by repeating measurements on membranes lacking endogenous cholesterol. E. coli cytoplasmic membranes lack cholesterol and were thus used to generate samples for SXS measurements. Membranes were characterized before and after protein depletion (Table 1 and Fig. 1G), and the bilayer thicknesses of each membrane sample were measured. Scattering curves, corrected for background and intensity, were generated in triplicate, and the average bilayer thickness, d, calculated from the second peak was 37.5 ± 0.5 Å. The thickness of liposomes of extracted lipids was measured to be 33.5 ± 0.4 Å, indicating that, even in prokaryotic membranes naturally lacking endogenous cholesterol, membrane proteins modulate bilayer thickness." For thickness of outer membrane see BNID 100015. For erythrocyte membrane thickness see BNID 103948
Entered by Ron Milo, Paul Jorgensen, Mike Springer
ID 100014