Fig 6.

Topological analysis and lipid interaction measured by solid-state NMR spectroscopy. (a) (Top) Proton-decoupled 1D ¹⁵N spectrum of 1.5 mg uniformly ¹⁵N-labeled HM1 reconstituted into 60 mg POPC-POPG (3:1 [mol/mol]) oriented bilayers for the membrane normal in parallel orientation to the external magnetic field direction. (Inset) The corresponding simulated ¹⁵N spectrum was obtained from the PDB file 2K35 in the manner indicated, with the x axis in plane with the bilayer normal. (b) Proton-decoupled 1D ³¹P spectra of oriented phospholipid bilayers composed of POPE-POPG (3:1) (top) or POPC-POPG (3:1) (bottom) alone (gray) or in the presence of 0.1 mol% HM1 (black) at 310 K. (c) 1D ²H quadrupolar-splitting spectra of unoriented POPC-d₃₁–POPG (3:1) vesicles were recorded alone (black solid line) or in the presence of 0.1 (black dotted line), 0.5 (gray dotted line), or 1.0 (gray solid line) mol% HM1 at 310 K. (d) Corresponding plot of the order parameter (S_CD) for each chain position of the membrane alone or in the presence of increasing HM1 concentrations.