@-tides as reporters for molecular associations.
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.
Phillips
Scott T
ST
Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Blasdel
Landy K
LK
Bartlett
Paul A
PA
D002942:Circular Dichroism; D019281:Dimerization; D009842:Oligopeptides / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry; D017433:Protein Structure, Secondary; D011728:Pyridones / Q000737:chemistry*; D013816:Thermodynamics
D009842:Oligopeptides; D010456:Peptides, Cyclic; D011728:Pyridones