Electronic Structure of Genomic DNA: A Photoemission and X-ray Absorption Study

Abstract

The electronic structure of genomic DNA has been comprehensively characterized by synchrotron-based X-ray absorption and X-ray photoelectron spectroscopy. Both unoccupied and occupied states close to the Fermi level have been unveiled and attributed to particular sites within the DNA structure. A semiconductor-like electronic structure with a band gap of approximately 2.6 eV has been found at which the pi and pi* orbitals of the nucleobase stack make major contributions to the highest occupied and lowest unoccupied molecular orbitals, respectively, in agreement with previous theoretical predictions.

Electronic structure, stacking energy, partial charge, and hydrogen bonding in four periodic B-DNA models

“…The electronic structure of DNA has been investigated both experimentally [8][9][10][11][12][13] and theoretically [14][15][16][17][18][19][20][21][22][23][24][25] for quite some time. Scanning tunneling spectroscopy and direct measurements of electrical conductivity have been used to explore the electronic structure of DNA but the results obtained were usually not consistent with each other due to differences in the specific experimental setups, the methods of sample preparation, and the ways that the experiments were conducted by different groups.…”

Insight into Bio-metal Interface Formation in vacuo: Interplay of S-layer Protein with Copper and Iron

“…This dipole-based beamline provides a moderate photon flux distributed continuously over a wide photon energy range from 30 to 1500 eV and, therefore, is particularly suited for radiation sensitive and fragile materials research5556. XPS spectra were acquired with a hemispherical Phoibos 150 electron energy analyzer (Specs GmbH).…”

Observation of cleavage in DNA and nucleotides following oxygenK-shell ionization by measuring X-ray absorption near edge structure

“…Th ere was no resonant peak structure (420 eV). Recently, Kummer et al (2010) reported Observation of DNA cleavage by XANES 891 peak was assigned to the electronic transition from the O 1s orbital to the unoccupied π * (N -C ϭ O) orbital. Figure 4 (a, c, e, g) shows the XANES spectra of each nucleotide (dAMP, TMP, dGMP, and dCMP) fi lm, respectively, around the nitrogen K -edge region following its exposure to 560 eV soft X-rays for 15 min (4 ϫ 10 14 photons), while Figure 4 (b, d, f, h) shows the diff erences between the spectra before and after irradiation.…”

“…Th ere was no resonant peak structure (550 eV). Kummer et al (2010) assigned the resonant peaks in the XANES spectrum of DNA fi lm. Th e peak at 531.5 eV Figure 4.…”