@article{oai:nitech.repo.nii.ac.jp:00004538,
 author = {Yamada, Keiichi and Ozaki, Hirotaka and Kanda, Naoki and Yamamura, Hatsuo and Araki, Shuki and Kawai, Masao},
 issue = {23},
 journal = {Journal of the Chemical Society. Perkin transactions 1 : organic and bio-organic chemistry.},
 month = {Jan},
 note = {Derivatives of gramicidin S (GS) in which one or both of the two ornithine side chains were picolinoylated were prepared. The dipicolinoyl derivative [Orn(PyCO)2,2′]GS 1 formed a 1:1 complex with Cu2+ and Zn2+ in MeOH, while in the case of the monopicolinoyl derivative [Orn(Boc)2,Orn(PyCO)2′]GS (2) stepwise formation of 1:1 and 2:1 (2:Cu2+) complexes was observed. The formation constant of the Cu2+-mediated dimeric species of compound 2 was larger than those of the corresponding linear compounds possessing the partial structure of macrocycle 2. The corresponding tetra-N-methyl derivative [MeOrn(Boc)2,MeOrn(PyCO)2′,D-MePhe4,4′]GS 3 also showed lower stability of the 2:1 complex compared with compound 2, which suggested the presence of a β-sheet-type intermolecular H-bonding interaction between the two molecules of macrocycle 2 in the 2:1 complex., application/pdf},
 pages = {3999--4004},
 title = {Preparation  and metal ion-binding properties of gramicidin S derivatives carrying picolinoyl groups on the ornithine side chains},
 volume = {1998},
 year = {1998}
}