A novel intramolecular hydrogen bonding between a side-chain pyridine ring and an amide hydrogen of the peptide backbone in tripeptides containing the new amino acid, alpha,alpha-di(2-pyridyl)glycine.
Four tripeptides (Z-AA1-2Dpy-AA3-OMe; AA1, AA3 = Gly, Aib) containing a novel amino acid, alpha, alpha-di(2-pyridyl)glycine (2Dpy), were synthesized by the modified Ugi reaction. NMR analysis clearly indicated that the 2Dpy-containing tripeptides except the peptide in which AA1, AA3 = Aib, adopt a unique conformation with two intramolecular hydrogen bonds between 2Dpy-NH and a pyridine nitrogen and between AA3-NH and another pyridine nitrogen. This conformation has so far not been reported. On the other hand, the peptide Z-Aib-2Dpy-Aib-OMe probably adopts a beta-turn structure which is stabilized by two intramolecular hydrogen bonds between 2Dpy-NH and a pyridine nitrogen and between AA3-NH and the C=O of the Z group.
Department of Chemistry, Faculty of Science and Engineering, Konan University, Kobe, Japan. yamada@konan-u.ac.jp
Takashi
T
Yamada
Tomoyuki
T
Ichino
Masayuki
M
Hanyu
Daisuke
D
Ninomiya
Ryoji
R
Yanagihara
Toshifumi
T
Miyazawa
Takashi
T
Murashima
D000577:Amides / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*
D000577:Amides; D009842:Oligopeptides; D011725:Pyridines; C510694:alpha,alpha-di(2-pyridyl)glycine; D006859:Hydrogen; C023666:pyridine; D005998:Glycine