Physicochemical characterization of glucagon-containing lipid micelles

Pulmonary surfactant‐associated polypeptide SP‐C in lipid micelles: CD studies of intact SP‐C and NMR secondary structure determination of depalmitoyl‐SP‐C(1–17)

“…The micelle-bound form of depalmitoyl-SP-C(1-17) was prepared following established procedures [14] [14,16,17]. A solution in 2H20 was prepared by twice lyophilizing this sample from 2H20, and redissolving it in 99.96% 2H20.…”

“…3) were determined by dissolving the lyophilized depalmitoyl-SP-C(1-17)/ [ZH38]DPC mixture in 2H20 and monitoring the time course of the amide proton signals at 34°C in a series of one-dimensional IH NMR spectra at 500 MHz. [14,16] solubilize native SP-C, and CD meas- urements (Fig. 2) indicate that the polypeptide is 80-90% helical in this environment.…”

The 21‐residue surfactant peptide (LysLeu4)4Lys(KL4) is a transmembrane α‐helix with a mixed nonpolar/polar surface

“…For analysis of secondary structure in phospholipid micelles, the KL4 peptide was solubilized in 20 mM dodecylphosphocholine (DPC [20]; critical micelle concentration ~ 1 mM [22])/50 mM sodium phosphate buffer, pH 6.0, and diluted to 10 mM DPC in the same buffer, giving a final peptide concentration of about 20 p.M. CD spectra between 260 and 184 nm were recorded at room temperature with a Jasco-720 instrument using a scan speed of 20 nm/min, a response time of 2 s, a band width of 1.0 nm, a sensitivity of 20 mdeg and a resolution of 2 data points/nm. The residual molar ellipticity was calculated after determination of the KL4 concentration by amino acid analysis and expressed in kdeg × cm2/dmol.…”

Lipid–protein interactions in DHPC micelles containing the integral membrane protein OmpX investigated by NMR spectroscopy

“…The potentialities of high-resolution NMR spectroscopy for studies of the architecture of mixed polypeptide-detergent micelles have long been recognized (16)(17)(18)(19), and the technique also has recently been applied with membrane protein fragments (20-22).…”

“…With reference to unfolding studies of the Escherichia coli outer membrane protein OmpA in micelles formed by detergent molecules with different chain lengths, Kleinschmidt et al (15) advanced the idea that a monolayer or a prolate ellipsoid arrangement of detergent molecules on the hydrophobic protein surface prevails in the mixed micelles. In this paper, we use solution NMR spectroscopy for further experimental studies of membrane protein-detergent interactions.The potentialities of high-resolution NMR spectroscopy for studies of the architecture of mixed polypeptide-detergent micelles have long been recognized (16)(17)(18)(19), and the technique also has recently been applied with membrane protein fragments (20-22).Here, we present a study of the intact integral outer membrane protein OmpX from E. coli in mixed micelles with dihexanoylphosphatidylcholine (DHPC) (11,12,23). Results on the solvation of OmpX by DHPC were obtained using 3D CH 3 ]-OmpX, was prepared as reported in ref.…”