title: Measuring screw-sense preference in a helical oligomer by comparison of 13C NMR signal separation at slow and fast exchange.
abstract: While an unequal population of rapidly interconverting left- and right-handed conformers of a helical oligomer can be detected by circular dichroism, precise quantification of a conformer ratio has not previously been achieved. We demonstrate, using a set of labeled peptide analogues, that simple analysis of peak separation in their (13)C NMR spectra at slow and fast exchange allows an accurate value for the ratio of helical conformers to be obtained. The method reports the ratio of conformers at the site of the label and can therefore be used to investigate local variations in helical conformational control.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Jordi
authors.initials: J
authors.lastname: Solà
authors.forename: Gareth A
authors.initials: GA
authors.lastname: Morris
authors.forename: Jonathan
authors.initials: J
authors.lastname: Clayden
mesh_terms: D002247:Carbon Isotopes; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D011108:Polymers / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D011108:Polymers