Two model tetrapeptides containing bicyclic analogues of either D- or L-proline were synthesised and their conformational properties were studied by NMR in different solvent systems and by molecular modelling techniques. Compound 1, with the bicyclic D-proline mimetic in the i+1 position, generated a unique trans isomer, and the peptide showed a well organised structure, in accordance with the tendency of Dproline to act as a good turn inducer with respect to its enantiomer. Peptide 2 displayed structures equilibrating from type I,II to type VI β-turns, thus confirming the hypothesised relationship between the chirality of BGS/Bgs and proline enantiomers on nucleating compact turns. Moreover, such behaviour suggested a tool for peptidomimetic design of reverse turn peptides containing BGS/Bgs bicyclic proline mimetics, as the choice of chirality might influence the generation either of compact γ- and β-turns or of flexible equilibrating reverse turn structures. The effect of solvent on conformational behaviour was also studied.
Solvent-Dependent Conformational Behaviour of Model Tetrapeptides Containing a Bicyclic Proline Mimetic / A. Trabocchi, D. Potenza, A. Guarna. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - :22(2004), pp. 4621-4627. [10.1002/ejoc.200400359]
Solvent-Dependent Conformational Behaviour of Model Tetrapeptides Containing a Bicyclic Proline Mimetic
D. PotenzaSecondo
;
2004
Abstract
Two model tetrapeptides containing bicyclic analogues of either D- or L-proline were synthesised and their conformational properties were studied by NMR in different solvent systems and by molecular modelling techniques. Compound 1, with the bicyclic D-proline mimetic in the i+1 position, generated a unique trans isomer, and the peptide showed a well organised structure, in accordance with the tendency of Dproline to act as a good turn inducer with respect to its enantiomer. Peptide 2 displayed structures equilibrating from type I,II to type VI β-turns, thus confirming the hypothesised relationship between the chirality of BGS/Bgs and proline enantiomers on nucleating compact turns. Moreover, such behaviour suggested a tool for peptidomimetic design of reverse turn peptides containing BGS/Bgs bicyclic proline mimetics, as the choice of chirality might influence the generation either of compact γ- and β-turns or of flexible equilibrating reverse turn structures. The effect of solvent on conformational behaviour was also studied.Pubblicazioni consigliate
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