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High Stability of the Polyproline II Helix in Polypeptide Bottlebrushes
Author(s) -
Zhang Afang,
Guo Yifei
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801191
Subject(s) - polyproline helix , side chain , circular dichroism , helix (gastropod) , chemistry , polymer , polymerization , dispersity , aqueous solution , polymer chemistry , degree of polymerization , crystallography , peptide , organic chemistry , biochemistry , ecology , snail , biology
Polymer bottlebrushes with monodisperse oligoproline side chains were efficiently synthesized, and the conformation of the peptide side chains in different solvents was investigated. Polymers with number‐average degrees of polymerization (DP n ) of 89 and 366 were obtained by polymerization of the macromonomer in i PrOH/MeCN (1:1) and hexafluoroisopropanol, respectively. Circular dichroism (CD) spectra of the bottlebrush polymers in the neutral and charged states reveal that the oligoproline side chains attain stable polyproline II (PPII) helical conformations not only in aqueous solution, but also in aliphatic alcohol solutions. Dense attachment of oligopeptides onto a linear polymer chain did not lead to an increase in helix content. The possible effects of the main‐chain length on the conformational stability were examined. The switching between the polyproline I (PPI) and PPII helical conformations for the oligoproline side chains in aliphatic alcohol solutions is believed to be inhibited by the overcrowded structure in the polymer bottlebrushes.