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A Pure Polyproline Type I‐like Peptoid Helix by Metal Coordination
Author(s) -
Zborovsky Lieby,
Smolyakova Alisa,
Baskin Maria,
Maayan Galia
Publication year - 2018
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.201704497
Subject(s) - peptoid , polyproline helix , circular dichroism , chemistry , helix (gastropod) , stereochemistry , folding (dsp implementation) , crystallography , side chain , peptidomimetic , two dimensional nuclear magnetic resonance spectroscopy , peptide , polymer , organic chemistry , ecology , biochemistry , snail , electrical engineering , biology , engineering
Peptoids, N‐substituted glycine oligomers, are an important class of foldamers that can adopt polyproline‐type helices (PP‐I and PP‐II), given that the majority of their sequence consists of chiral, bulky side chains. Herein a new approach for the stabilization of a pure PP‐I‐like peptoid helix through metal coordination is introduced. A systematic spectroscopic study was performed on a series of peptoid heptamers bearing two 8‐hydroxyquinoline ligands at fixed positions, and a mixture of chiral benzyl and alkyl substituents in varied positions along the peptoid backbone. When the benzyl groups are located at the 3rd and 4th positions, the peptoid ( 7P6 ) gives upon Cu 2+ binding a circular dichroism (CD) signal similar to that of a PP‐I helix. Exciton couplet CD spectroscopy and EPR spectroscopy, as well as modifications to the length of 7P6 and derivatization through acetylation provided insights into the unique folding of 7P6 upon Cu binding, showing that it is led by two competing driving forces, namely coordination geometry and sequence.