Premium
Synthesis and interfacial behavior of poly(Lys‐Tyr‐Tyr‐Lys)
Author(s) -
MagetDana Régine,
Bolbach Gérard,
Trudelle Yves
Publication year - 1995
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360350609
Subject(s) - chemistry , random coil , tetrapeptide , polymer , monolayer , antiparallel (mathematics) , crystallography , stacking , infrared spectroscopy , spectral line , stereochemistry , circular dichroism , organic chemistry , peptide , biochemistry , physics , quantum mechanics , astronomy , magnetic field
Abstract Poly(Lys‐Tyr‐Tyr‐Lys) was synthesized by polycondensation of the tetrapeptide unit using paranitrophenyl esters. The conformation of poly (Lys‐Tyr‐Tyr‐Lys) is very dependent on its environment. CD spectra in bulk are difficult to interpret owing to the contribution of Tyr residues, but from ir spectra it seems that poly(Lys‐Tyr‐Tyr‐Lys) adopts preferentially an unordered conformation in water. Addition of salts induces a partial transition to a β structure. The behavior is different at interfaces. When poly(Lys‐Tyr‐Tyr‐Lys) is spread as a film on a water subphase, the shape of the compression isotherm curves is compatible with a stacking of two β‐sheets. On a KCl subphase, the polymer film is more expanded and more compressible, and the isotherm curve resembles that of a polymer in a random conformation. The analysis by CD and ir spectroscopy of transferred monolayers using the Langmuir–Blodgett technique allowed us to confirm and make these data more precise: on a water subphase the spectra are those of an antiparallel β structure. At the interface of a saline solution the spectra are compatible with a mixture of random coil (largely) and a small content of β structures. © 1995 John Wiley & Sons, Inc.