Controlling Glycosyl Bond Conformation of Guanine Nucleosides: Stabilization of the anti Conformer in 5'-O-Ethylguanosine.
Nucleosides that consist of base and sugar moieties can adopt two main conformations, syn and anti, about the glycosidic bond. We have investigated the conformational properties of guanine nucleosides in the gas phase by using laser desorption combined with IR-UV double resonance spectroscopy. In guanosine, syn conformation is preferred as a result of internal hydrogen bonding between the 5'-OH group of the sugar and the N3 site of the guanine moiety. We have therefore employed a chemically modified nucleoside 5'-O-ethylguanosine, in which possible glycosyl bond conformations are restricted upon ethylation of the 5'-OH group. The result shows that anti conformer is stabilized by the formation of hydrogen bonding involving the 2'-OH group.
†Graduate School of Bio- and Nanosystem Sciences, Yokohama City University, Yokohama 236-0027, Japan.
Hiroya
H
Asami
†Graduate School of Bio- and Nanosystem Sciences, Yokohama City University, Yokohama 236-0027, Japan.
Shu-Hei
SH
Urashima
‡Graduate School of Information Science, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Masaki
M
Tsukamoto
‡Graduate School of Information Science, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Ayaka
A
Motoda
§Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa Cho, Toyota 470-0392, Japan.
Yoshihiro
Y
Hayakawa
†Graduate School of Bio- and Nanosystem Sciences, Yokohama City University, Yokohama 236-0027, Japan.
Hiroyuki
H
Saigusa
IR−UV double resonance spectroscopy; glycosidic bond; guanine nucleoside; laser desorption; syn and anti conformers