Annette R. Atkins

Conformation of sarafotoxin-6b in aqueous solution determined by NMR spectroscopy and distance geometry

The solution structure of sarafotoxin‐6b in water has been determined using high‐resolution NMR spectroscopy, 127 proton‐proton distance measurements and three ω dihedral angle constraints derived from NMR spectra were used to calculate the solution structure using a combination of distance geometry and restrained molecular dynamics. The major structural feature of the resulting family of five structures was a right‐handed α‐helix extending from K9 to Q17. In contrast, the C‐terminal region of the peptide appears not to adopt a preferred conformation in aqueous solution. The present structure is compared with those previously determined for endothelin peptides in non‐aqueous solvents.

Effect of acyl chain length on the structure and motion of gramicidin A in lipid bilayers

The transmembrane ion transport properties of gramicidin A have previously been shown to dependent on the nature of its lipid environment. Solid-state NMR spectroscopic studies of 13C-labelled analogues of gramicidin in oriented multilayers of phosphatidylcholine have shown that variation of the lipid hydrocarbon chain length has no effect on the structure or orientation of the peptide backbone.

Shark myelin basic protein : amino acid sequence, secondary structure, and self-association

Abstract: Myelin basic protein (MBP) from the Whaler shark (Carcharhinus obscurus) has been purified from acid extracts of a chloroform/methanol pellet from whole brains. The amino acid sequence of the majority of the protein has been determined and compared with the sequences of other MBPs. The shark protein has only 44% homology with the bovine protein, but, in common with other MBPs, it has basic residues distributed throughout the sequence and no extensive segments that are predicted to have an ordered secondary structure in solution. Shark MBP lacks the triproline sequence previously postulated to form a hairpin bend in the molecule. The region containing the putative consensus sequence for encephalitogenicity in the guinea pig contains several substitutions, thus accounting for the lack of activity of the shark protein. Studies of the secondary structure and self‐association have shown that shark MBP possesses solution properties similar to those of the bovine protein, despite the extensive differences in primary structure.