Surface active properties of amphiphilic sequential isopeptides: Comparison between α-helical and β-sheet conformations
✍ Scribed by Régine Maget-Dana; Dominique Lelièvre; André Brack
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1999
- Tongue
- English
- Weight
- 155 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Poly(Leu-Lys-Lys-Leu) and poly(Leu-Lys) are sequential amphiphilic peptide isomers that adopt respectively an ␣-helical conformation and a -sheet structure in saline solutions and at the air/water interface. The surface active properties of LKKL and LK sequential isopeptides containing 16, 20, and n residues have been compared in order to evaluate the contributions of the ␣-helical and -sheet conformations. Both have a natural tendency to spread at the surface of a saline solution and the values of the equilibrium spreading pressure e lie in the same range. When dissolved in a saline solution, ␣-helical peptides diffuse faster and adsorb faster at the interface than the -sheet isomers. From the compression isotherms of LKKL and LK peptide monolayers it is possible to extract parameters that characterize the behavior of ␣-helical and -sheet conformations: -sheet peptide monolayers are more stable and less compressible than the monolayers formed with the ␣-helical isomers. The LK peptides differ also by their high degree of selfassociation at the air/water interface.