Electronic structure of DNA nucleobases and their dinucleotides explored by soft X-ray spectroscopy.
The electronic structures of a series of DNA nucleobases and their dinucleotides were investigated by N 1s X-ray absorption, X-ray photoemission, and resonant X-ray emission spectroscopy. Resonant X-ray emission spectra of the guanine base and its dinucleotide indicate that it has a weak structure at the lowest binding energy; at this energy, it isolates from the main valence band and forms the HOMO state. This indicates that the HOMO state is localized in the guanine base, as claimed by valence and core photoemissions and expected from theoretical predictions. In addition, the XAS and XES profiles of the guanine dinucleotide indicate that disruption of the aromatic character of the six-membered ring results in the localization of the pi state at the imine (-N=) site of the guanine base; this may favor charge transfer among stacked guanine bases and further influence the conductivity of DNA.
Harada
Yoshihisa
Y
Riken SPring-8 Center, 1-1-1 Kouto Sayo-cho Sayo-gun Hyogo 679-5148, Japan, National Institute for Materials Science, 1-2-1 Sengen Tsukuba Ibaraki 305-0047, Japan. harada@spring8.or.jp
Takeuchi
Tomoyuki
T
Kino
Hiori
H
Fukushima
Akiko
A
Takakura
Kaoru
K
Hieda
Kotaro
K
Nakao
Aiko
A
Shin
Shik
S
Fukuyama
Hidetoshi
H
D000225:Adenine / Q000737:chemistry; D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004583:Electrons; D006147:Guanine / Q000737:chemistry; D011685:Purine Nucleotides / Q000737:chemistry*; D011742:Pyrimidine Nucleotides / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013057:Spectrum Analysis; D013941:Thymine / Q000737:chemistry; D014965:X-Rays
D011685:Purine Nucleotides; D011742:Pyrimidine Nucleotides; D006147:Guanine; D003596:Cytosine; D004247:DNA; D000225:Adenine; D013941:Thymine