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Handedness control of peptide helices by amino acid side‐chain chirality: Ile/ a Ile peptides
Author(s) -
Andreetto Erika,
Peggion Cristina,
Crisma Marco,
Toniolo Claudio
Publication year - 2006
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20534
Subject(s) - chemistry , chirality (physics) , diastereomer , peptide , crystallography , carbon atom , side chain , asymmetric carbon , stereochemistry , amino acid , tetrapeptide , ring (chemistry) , organic chemistry , optically active , biochemistry , chiral symmetry , physics , quantum mechanics , nambu–jona lasinio model , quark , polymer
A set of four hexapeptide sequences, each characterized by four strongly helicogenic Aib residues and all combinations of two isomeric Ile/ a Ile residues at positions 2 and 5, was synthesized by solution methods and fully characterized. A detailed solution (by FT–IR absorption, NMR, and CD techniques) and solid/crystalline state (by X‐ray diffraction) conformational investigation allowed us to validate our assumption that all four peptides are folded in well‐developed 3 10 ‐helical structures. However, the most relevant conformational conclusion extracted from the present 3D‐analysis is that the handedness of the 3 10 ‐helical structures formed does not seem to be sensitive to the configurational change at the β‐carbon atom of the constituent Ile versus the diastereomeric a Ile residues (in other words, the dominant control on this important structural parameter appears to be exerted by the chirality of the amino acid α‐carbon atom). These results complement published findings on the diverging relative stabilities of the intermolecularly H‐bonded β‐sheet structures generated by Ile versus a Ile homo‐oligopeptides. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 490–501, 2006 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com