title: Nucleation of beta-hairpin structures with cis amide bonds in E-vinylogous proline-containing peptides.
abstract: Synthesis and conformational studies of peptides containing the E-vinylogous prolines 1 (VPro1) and 2 (VPro2), Boc-Ala-Val-VPro1-Xaa-Leu-OMe (3, Xaa = Gly; 4, Xaa = Phe), Boc-Ala-Val-VPro2-Xaa-Leu-OMe (5, Xaa = Gly; 6, Xaa = Phe), Boc-Leu-Ile-Val-VPro1-Xaa-Leu-OMe (7, Xaa = Gly; 8, Xaa = Phe), and Boc-Leu-Ile-Val-VPro2-Xaa-Leu-OMe (9, Xaa = Gly; 10, Xaa = Phe), were carried out. It has been shown that both VPro1 and VPro2 lead to the formation of 12-membered intramolecularly hydrogen bonded structures very similar to type VI beta-turns with a cis Xaa-VPro amide bond in the major conformers in all the peptides 3-10, resulting in the nucleation of beta-hairpin type structures in these molecules in CDCl(3).
authors.affiliation: Indian Institute of Chemical Technology, Hyderabad 500 007, India. chakraborty@iict.ap.nic.in
authors.forename: Tushar K
authors.initials: TK
authors.lastname: Chakraborty
authors.forename: Animesh
authors.initials: A
authors.lastname: Ghosh
authors.forename: S Kiran
authors.initials: SK
authors.lastname: Kumar
authors.forename: Ajit C
authors.initials: AC
authors.lastname: Kunwar
mesh_terms: D006860:Hydrogen Bonding; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009690:Nucleic Acid Conformation; D010455:Peptides / Q000138:chemical synthesis*; D011392:Proline / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D010455:Peptides; D011392:Proline