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Flat, C α,β ‐Didehydroalanine Foldamers with Ferrocene Pendants: Assessing the Role of α‐Peptide Dipolar Moments
Author(s) -
Santi Saverio,
Bisello Annalisa,
Cardena Roberta,
Tomelleri Silvia,
Schiesari Renato,
Biondi Barbara,
Crisma Marco,
Formaggio Fernando
Publication year - 2021
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.202100072
Subject(s) - tetrapeptide , foldamer , chemistry , helix (gastropod) , dipole , peptide , crystallography , ferrocene , molecule , stereochemistry , electrochemistry , organic chemistry , ecology , biochemistry , electrode , snail , biology
The foldamer field is continuously expanding as it allows to produce molecules endowed with 3D‐structures and functions never observed in nature. We synthesized flat foldamers based on the natural, but non‐coded, C α,β ‐didehydroalanine α‐amino acid, and covalently linked to them two ferrocene (Fc) moieties, as redox probes. These conjugates retain the flat and extended conformation of the 2.0 5 ‐helix, both in solution and in the crystal state (X‐ray diffraction). Cyclic voltammetry measurements agree with the adoption of the 2.0 5 ‐helix, characterized by a negligible dipole moment. Thus, elongated α‐peptide stretches of this type are insulators rather than charge conductors, the latter being constituted by peptide α‐helices. Also, our homo‐tetrapeptide has a N‐to‐C length of about 18.2 Å, almost double than that (9.7 Å) of an α‐helical α‐tetrapeptide.