Structural changes of nucleic acid base in aqueous solution as observed in X-ray absorption near edge structure (XANES)

X線吸収端微細構造(XANES)測定による水溶液中の核酸塩基の構造変化

島田 紘行*; 深尾 太志*; 南 寛威*; 鵜飼 正敏*; 藤井 健太郎; 横谷 明徳; 福田 義博*; 斎藤 祐児  

Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

X-ray absorption near edge structure (XANES) spectra for adenine containing nucleotides, adenosine 5'-monophosphate (AMP) and adenosine 5'-triphosphate (ATP) in aqueous solutions at the nitrogen K-edge region were measured. The two intense peaks in XANES spectra are assigned to transitions of 1s electrons to the orbitals of different types of N atoms with particular bonding characteristics. The difference between their spectra is ascribed to protonation of a particular N atom. Similarity observed in XANES spectra of guanosine-5'-monophosphate (GMP) and ATP is also interpreted as similar bonding characters of the N atoms in the nucleobase moiety.