title: Application of the TORO technique of 1H NMR to the structural analysis of cyclic peptide isomers having a slightly distorted symmetry from C2.
abstract: The extended TORO technique was applied to the structural analysis of endo-D-Tyr-gramicidin S, cyclo(-Val-Orn-Leu-D-Phe-D-Tyr-Pro-Val-Orn-Leu-D-Phe-Pro-), which has a slightly distorted symmetry from C2, by the insertion of D-Tyr and equivalent alpha-proton chemical shifts in the 1H NMR spectrum. All NMR signals of the two dominant isomers of this antibiotic with trans-trans prolines were determined by using the extended TORO technique with TOCSY and ROESY spectra. This technique is generally applicable for distinguishing overlapped signals of alpha- and amide protons from the main chains of peptides.
authors.affiliation: Department of Chemistry, Rikkyo (St. Paul's) University, Toshima-ku, Tokyo 171-8501, Japan. eiji-jun@umin.ac.jp
authors.forename: Eiji
authors.initials: E
authors.lastname: Watanabe
authors.forename: Makoto
authors.initials: M
authors.lastname: Tamaki
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Yamakura
authors.forename: Minoru
authors.initials: M
authors.lastname: Akiyama
mesh_terms: D006859:Hydrogen; D007536:Isomerism; D007554:Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D007554:Isotopes; D010456:Peptides, Cyclic; D006859:Hydrogen