Detailed Comparison of Deuterium Quadrupole Profiles between Sphingomyelin and Phosphatidylcholine Bilayers  Tomokazu Yasuda, Masanao Kinoshita, Michio Murata, Nobuaki Matsumori  Biophysical Journal  Volume 106, Issue 3, Pages 631-638 (February 2014) DOI: 10.1016/j.bpj.2013.12.034 Copyright © 2014 Biophysical Society Terms and Conditions

Figure 1 Site-specifically deuterated PSPCs. (a) Structures of site-specifically deuterated PSPC and SSM. Each numbered position was deuterium labeled. C-18′ was trideuterated and the other positions were dideuterated. (b) Synthesis of PSPCs deuterated at sn-2 chain. A total of 10 types of deuterium-labeled PSPCs (2′-d2-, 3′-d2-, 4′-d2-, 6′-d2-, 8′-d2-, 10′-d2-, 12′-d2-, 14′-d2-, 16′-d2-, and 18′-d3-PSPCs) were synthesized to capture the motion of PSPC in bilayers. MNBA: 2-methyl-6-nitrobenzoic anhydride, DMAP: N,N-dimethyl-4-aminopyridine. To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 2 Quadrupole splitting profiles of sn-2 chain of PSPC at various temperatures. The data were obtained from PSPC membranes in the absence (a) and presence (b) of 50 mol % Chol. Both membrane samples were hydrated with 50% deuterium-depleted water (w/w). To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 3 Comparison of quadrupole splitting profiles between PSPC and SSM membranes at 50°C. The data were acquired from PSPC (a) and SSM (b) membranes in the presence (circles) and absence (triangles) of 50 mol % Chol. Overlaid quadrupole splitting profiles of PSPC (red) and SSM (blue) membranes in the absence (c) and presence (d) of 50 mol % Chol. To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 4 Ordering effect of Chol on PSPC and SSM membranes. Figure presents difference in quadrupole splitting values (ΔΔν) between Chol-containing and Chol-free PSPC (red squares) and SSM (blue circles) membranes at 50°C. To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 5 Temperature dependence of quadrupole splittings. The quadrupole coupling data were obtained from the C4′ (a), C8′ (b), C12′ (c), and C16′ (d) positions of PSPC (red) and SSM (blue) in the presence and absence of 50 mol % Chol. The temperature dependence of Chol-containing membranes can be linearly approximated, as presented in red and blue lines with approximate equations. To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 6 Temperature dependence of quadrupole splittings at various Chol concentrations. The quadrupole coupling data were obtained from C10′ of PSPC (red) and SSM (blue) acyl chains in the presence of Chol at (a) 50 mol %, (b) 33 mol %, and (c) 20 mol %. The temperature dependence of SSM-Chol and PSPC-Chol membranes can be linearly approximated, as presented in red and blue lines with approximation equations. To see this figure in color, go online. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions

Figure 7 DSC heating curves. PSPC (a) and SSM (b) bilayers containing 0, 10, 20, and 30 mol % Chol. Biophysical Journal 2014 106, 631-638DOI: (10.1016/j.bpj.2013.12.034) Copyright © 2014 Biophysical Society Terms and Conditions