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rdf:type
lifeskim:mentions
pubmed:issue
32
pubmed:dateCreated
2007-8-10
pubmed:abstractText
gamma-Turn, the shortest secondary structure of peptides, exists as two helical forms gamma(l) and gamma(d) of opposite handedness. The present gas phase study of capped l-Phe-Xxx peptides (Xxx = l-Ala, d-Ala or Aib: aminoisobutyric acid) provides a unique example of intramolecular chiral recognition of the gamma-turn helicity on Ala or Aib by the neighbouring residue Phe within the chain. With the chiral l- or d-Ala residues, the presence of a side-chain operates a discrimination between the two helical forms: one of them is widely favoured over the other (gamma(l) or gamma(d), respectively). This enables us to validate and calibrate the recognition capabilities of the nearby l-Phe residue. The discriminating interactions have been precisely characterized from their spectroscopic UV and IR signatures and identified by comparison with quantum chemistry calculations. Then, in the case of the non-chiral residue Aib, the two helical forms of the gamma-turn, which are simultaneously observed in the jet, have been discriminated and assigned by comparison with the chiral residues. The relative abundances of the diastereomeric forms l-Phe-Aib(gamma(l)) and l-Phe-Aib(gamma(d)) enable us to determine the most efficient recognition configuration.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1463-9076
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4491-7
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Intramolecular recognition in a jet-cooled short peptide chain: gamma-turn helicity probed by a neighbouring residue.
pubmed:affiliation
Laboratoire Francis Perrin, URA CEA-CNRS 2453, Service des Photons, Atomes et Molécules, CEA Saclay, Bât 522, 91191 Gif-sur-Yvette cedex, France.
pubmed:publicationType
Journal Article