A SINGLE POINT CHIRAL INVERSION THAT SELFORGANIZES A RANDOMCOIL PEPTIDE. APOLAR SOLVENT CONFORMATION OF BOC-(L/D)-GLU-ALA-LEU-LYSNHME

Abstract The tetrapeptide Boc- L -Glu-Ala-Leu-LysNHMe ( 1 ) reveals a random coil conformation, based on its Glu(γ) and Lys(ɛ) methylene proton aniosotropic shift, GluNH chemical shift, NOEs in chloroform-DMSO (6:1), and its amide proton temperature coefficients in DMSO, while on similar considerations, the diastereomer Boc- D -Glu-Ala-Leu-LysNHMe ( 2 ) is characterized as a highly ordered 3/10 type distorted protohelix with a remarkably stable intramolecular salt bridge under these solvent conditions.