Molecular structure heterogeneity of gramicidin analogs incorporated into SDS micelles: a NMR study
by Hinton, J. F.; Jordan, B.; Horne, E.
The effects of glycine, alanine and valine substitution for leucine upon the species heterogeneity of gramicidin A incorporated into SDS micelles have been investigated. The sequential replacement of the leucine residues at positions 10, 12 and 14 produced multiple beta-helical forms of the gramicidin A analogs as shown by (1)H NMR spectroscopy. These results reveal the complexity of the interaction of amino acid residue side chain with the SDS micelle environment in controlling the formation of a single channel species or multiple helical forms. Clearly, a potential problem may arise if one assumes that the solubilization of the peptide, gramicidin, in micelles indicates the existence of a single form of the peptide.