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Antiparallel Self‐Association of a γ,α‐Hybrid Peptide: More Relevance of Weak Interactions
Author(s) -
Venugopalan Paloth,
Kishore Raghuvansh
Publication year - 2015
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201500373
Subject(s) - antiparallel (mathematics) , intramolecular force , chemistry , supramolecular chemistry , peptide , crystallography , amide , hydrogen bond , stereochemistry , moiety , foldamer , molecule , crystal structure , physics , biochemistry , organic chemistry , quantum mechanics , magnetic field
To learn how a preorganized peptide‐based molecular template, together with diverse weak non‐covalent interactions, leads to an effective self‐association, we investigated the conformational characteristics of a simple γ,α‐hybrid model peptide, Boc‐γ‐Abz‐Gly‐OMe. The single‐crystal X‐ray diffraction analysis revealed the existence of a fully extended β‐strand‐like structure stabilized by two non‐conventional C−H⋅⋅⋅O=C intramolecular H‐bonds. The 2D 1 H NMR ROESY experiment led us to propose that the flat topology of the urethane‐γ‐Abz‐amide moiety is predominantly preserved in a non‐polar environment. The self‐association of the energetically more favorable antiparallel β‐strand‐mimic in solid‐state engenders an unusual ‘flight of stairs’ fabricated through face‐to‐face and edge‐to‐edge Ar⋅⋅⋅Ar interactions. In conjunction with FT‐IR spectroscopic analysis in chloroform, we highlight that conformationally semi‐rigid γ‐Abz foldamer in appositely designed peptides may encourage unusual β‐strand or β‐sheet‐like self‐association and supramolecular organization stabilized via weak attractive forces.