Cystine peptides. The anti parallel β-sheet conformation of two synthetic cyclic bi(cystine peptides)

Kishore, R. ; Anil Kumar, ; Balaram, P. (1985) Cystine peptides. The anti parallel β-sheet conformation of two synthetic cyclic bi(cystine peptides) Journal of the American Chemical Society, 107 (26). pp. 8019-8023. ISSN 0002-7863

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Official URL: http://pubs.acs.org/doi/abs/10.1021/ja00312a036

Related URL: http://dx.doi.org/10.1021/ja00312a036

Abstract

Conformational studies on two synthetic cyclic bis(cystine peptides) have been carried out. The NMR data support a C2-symmetric structure possessing four intramolecular hydrogen bonds in CDCl3 and (CD3)2SO solutions. The involvement of the X-NH and NHMe groups in formation of transannular hydrogen bonds is inferred from the temperature and solvent dependences of NH chemical shifts, hydrogen-deuterium-exchange rates, and radical-induced line-broadening experiments. IR studies over a wide concentration range also favor hydrogen-bonded structures. Unusually low CαH chemical shifts for Cys1 and Cys3 residues, high JHNCαH values (≥9 Hz), and the observation of nuclear Overhauser effects between CiαH and Ni+1H protons in 1 provide compelling evidence for an antiparallel α-sheet conformation for the 22-membered cyclic bis(cystine peptides).

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:72799
Deposited On:02 Jul 2012 10:37
Last Modified:13 Jul 2012 16:48

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