title: Controlling the helical screw sense of peptides with C-terminal L-valine.
abstract: One chiral L-valine (L-Val) was inserted into the C-terminal position of achiral peptide segments constructed from alpha-aminoisobutyric acid (Aib) and alpha,beta-dehydrophenylalanine (Delta(Z)Phe) residues. The IR, (1)H NMR and CD spectra indicated that the dominant conformations of the pentapeptide Boc-Aib-DeltaPhe-(Aib)(2)-L-Val-NH-Bn (3) and the hexapeptide Boc-Aib-DeltaPhe-(Aib)(3)-L-Val-NH-Bn (4) in solution were both right-handed (P) 3(10)-helical structures. X-ray crystallographic analyses of 3 and 4 revealed that only a right-handed (P) 3(10)-helical structure was present in their crystalline states. The conformation of 4 was also studied by molecular-mechanics calculations.
authors.affiliation: Division of Organic Chemistry, National Institute of Health Sciences, Tokyo 158-8501, Japan. demizu@nihs.go.jp
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Demizu
authors.forename: Nanako
authors.initials: N
authors.lastname: Yamagata
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Sato
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Doi
authors.forename: Masakazu
authors.initials: M
authors.lastname: Tanaka
authors.forename: Haruhiro
authors.initials: H
authors.lastname: Okuda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kurihara
mesh_terms: D002942:Circular Dichroism; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D014633:Valine / Q000737:chemistry*
chemical_list: D010455:Peptides; D014633:Valine