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Article Dans Une Revue Physical Chemistry Chemical Physics Année : 2006

Probing the competition between secondary structures and local preferences in gas phase isolated peptide backbones

Résumé

Combining laser desorption with a supersonic expansion together with the selectivity of IR/UV double resonance spectroscopy makes it possible to isolate and characterise the gas phase of remarkable backbone conformations of short peptide chains mimicking protein segments. A systematic bottom-up approach involving a conformer-specific IR study of peptide sequences of increasing sizes has enabled us to map the spectral signatures of the intramolecular interactions, which shape the peptide backbone, in particular H-bonds. The precise data collected are directly comparable to the most sophisticated quantum chemistry calculations of these species and therefore constitute a stringent test for the theoretical methods used. One-residue chains reveal the local conformational preference of the backbone and its dependence upon the nature of the residue. The investigation of longer chains provides evidence for a competition between simple successions of local conformational preferences along the chain and more folded structures, in which a new H-bonding network, involving distant H-bonding sites along the backbone, takes place. From three residues, the issue of helical folding can also be addressed. The present review of the gas phase literature data emphasizes the observation of remarkable secondary structures of biology, including short segments of b-strands, g- and b-turns, combinations of turns, including a 310 helix. It also provides evidence for the flexibility of the peptide chains, i.e., a critical influence of rather minor interactions (like side-chain/backbone interactions) on the conformational stability. Finally, the paper will discuss future promising directions of the present approach.

Dates et versions

hal-00083864 , version 1 (04-07-2006)

Identifiants

Citer

W. Chin, Piuzzi François, I. Dimicoli, M. Mons. Probing the competition between secondary structures and local preferences in gas phase isolated peptide backbones. Physical Chemistry Chemical Physics, 2006, 8, pp.1033 - 1048. ⟨10.1039/b516245a⟩. ⟨hal-00083864⟩
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