NMR-Structural Studies of Membrane Bound Peptides and Proteins

fd coat protein structure in membrane environments: structural dynamics of the loop between the hydrophobic trans-membrane helix and the amphipathic in-plane helix

“…The earlier studies are in broad agreement in demonstrating that the secondary structure of the membrane-bound form of the protein consists of a short amphipathic helix and a long hydrophobic helix (Henry & Sykes, 1992;van de Ven et al, 1993). Solid state NMR studies of the fd coat protein in phospholipid bilayers demonstrated that the amphipathic helix lies in the plane of the bilayer (Shon et al, 1991a;Marassi, et al, 1997). A similar arrangement of the two helices was also deduced from the effects of electron spin-labels on the NMR signals in micelles (Papavoine et al, 1994(Papavoine et al, , 1995.…”

“…This means that the overall backbone RMSD serves primarily as a measure of the precision of the angle between the two helices, since the RMSD values for the helical regions alone are close to the ®nal ones listed in Table 2. The angle between the two helices is approximately 90 in the calculated structures in agreement with experimental solid-state NMR data for the protein in bilayers (Shon et al, 1991a;. The inter-helical angle was determined solely on the basis of short-range NOEs between residues connecting the two helices, since no inter-helical NOEs are observed.…”

“…The overall architecture of the membrane-bound form of fd coat protein has been established though a combination of solution NMR experiments on micelle samples and solid-state NMR experiments on oriented bilayer samples (Shon et al, 1991a;. By using highly optimized samples of fd coat protein in SDS micelles and measuring 1 H homonuclear NOEs at 750 MHz it was possible to obtain suf®cient data to charac- terize many structural details of this membrane protein, including for the residues between the two helices.…”

“…It is very hydrophobic and completely insoluble in water when separated from virus particles or membranes. In membrane environments the protein has two distinct a-helical segments, a short nine residue amphipathic helix that lies in the plane of the bilayer and a long 18 residue trans-membrane hydrophobic helix (Shon et al, 1991a;. The structure and dynamics of the nine residues located between the two helices are of interest and are the principal subjects of this paper.…”

Structure and orientation of the antibiotic peptide magainin in membranes by solid‐state nuclear magnetic resonance spectroscopy

“…This comparison indicates that only very limited motional averaging occurs when magainin 2 interacts with phospholipids. In the absence of phospholipids, the peptide is highly flexible in aqueous solution, and the ISN resonance is a narrow single line (Shon et al, 1991b).…”