title: @-tides as reporters for molecular associations.
abstract: The 1,6-dihydro-3(2H)-pyridinone unit is an amino acid surrogate that favors the extended beta-strand conformation when incorporated in an oligopeptide ("@-tide") strand. We now report that the circular dichroism (CD) signature of the vinylogous amide in the @-unit is sensitive to conformation in organic and aqueous solvents and, therefore, is useful as a quantitative measure of @-tide association and folding processes that involve this moiety. Moreover, this method can be employed in the micromolar concentration range, which is not readily accessible using other techniques. Measurements of @-tide dimerization and beta-hairpin folding equilibria not only demonstrate the utility and generality of this approach but also provide a way to quantify amino acid side chain-side chain interactions relevant to beta-sheet stability.
authors.affiliation: Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Phillips
authors.forename: Landy K
authors.initials: LK
authors.lastname: Blasdel
authors.forename: Paul A
authors.initials: PA
authors.lastname: Bartlett
mesh_terms: D002942:Circular Dichroism; D019281:Dimerization; D009842:Oligopeptides / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry; D017433:Protein Structure, Secondary; D011728:Pyridones / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009842:Oligopeptides; D010456:Peptides, Cyclic; D011728:Pyridones