title: Stretch-Induced Helical Conformations in Poly(l-lysine)/Hyaluronic Acid Multilayers.
abstract: We investigate the effect of stretching on the secondary structure of cross-linked poly(l-lysine)/hyaluronic acid (PLL/HA) multilayers. We show that stretching these films induces changes in the secondary structure of PLL chains. Our results suggest that not only α- but also 310-helices might form in the film under stretching. Such 310-helices have never been observed for PLL so far. These changes of the secondary structure of PLL are reversible, i.e., when returning to the nonstretched state one recovers the initial film structure. Using molecular dynamics simulations of chains composed of 20 l-lysine residues (PLL20), we find that these chains never adopt a helical conformation in water. In contrast, when the end-to-end distance of the chains is restrained to values smaller than the mean end-to-end distance of free chains, a distance domain rarely explored by the free chains, helical conformations become accessible. Moreover, the formation of not only α- but also 310-helices is predicted by the simulations. These results suggest that the change of the end-to-end distance of PLL chains in the stretched film is at the origin of the helix formation.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann, 67085 Strasbourg Cedex, France.|Faculté de Chirurgie Dentaire, Université de Strasbourg , 8 rue Sainte Elisabeth, 67000 Strasbourg, France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Zahouani
authors.affiliation: Faculté de Chimie, UMR 7177, Université de Strasbourg , 1 rue Blaise Pascal, 67008 Strasbourg Cedex, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Chaumont
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann, 67085 Strasbourg Cedex, France.|Faculté de Chirurgie Dentaire, Université de Strasbourg , 8 rue Sainte Elisabeth, 67000 Strasbourg, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Senger
authors.affiliation: Institut Charles Sadron, CNRS UPR 22 , 23 rue du Lœss, 67034 Strasbourg Cedex, France.|University of Strasbourg Institute of Advanced Study , 5 allée du Général Rouvillois, 67083 Strasbourg Cedex, France.
authors.forename: Fouzia
authors.initials: F
authors.lastname: Boulmedais
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann, 67085 Strasbourg Cedex, France.|Faculté de Chirurgie Dentaire, Université de Strasbourg , 8 rue Sainte Elisabeth, 67000 Strasbourg, France.|Institut Charles Sadron, CNRS UPR 22 , 23 rue du Lœss, 67034 Strasbourg Cedex, France.|University of Strasbourg Institute of Advanced Study , 5 allée du Général Rouvillois, 67083 Strasbourg Cedex, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Schaaf
authors.affiliation: Institut Charles Sadron, CNRS UPR 22 , 23 rue du Lœss, 67034 Strasbourg Cedex, France.|University of Strasbourg Institute of Advanced Study , 5 allée du Général Rouvillois, 67083 Strasbourg Cedex, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Jierry
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, INSERM Unité 1121 , 11 rue Humann, 67085 Strasbourg Cedex, France.|Faculté de Chirurgie Dentaire, Université de Strasbourg , 8 rue Sainte Elisabeth, 67000 Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lavalle
mesh_terms: D006820:Hyaluronic Acid; D011107:Polylysine / Q000737:chemistry*; D017433:Protein Structure, Secondary; D014867:Water
chemical_list: D014867:Water; D011107:Polylysine; D006820:Hyaluronic Acid
keywords: circular dichroism; mechanoresponsive materials; molecular dynamics; polyelectrolyte multilayers; secondary structure