Stability and electronic structure of M-DNA: Role of metal position

Article

关键词: BASE-PAIR;    PSEUDOPOTENTIALS;    COORDINATION;    TRANSPORT;    GUANINE;    MODEL;   

DOI  :  10.1103/PhysRevB.84.045413

来源: SCIE

【 摘 要 】

We investigate, by first-principles density-functional calculations, fragments and periodic helices of CG- and AT-DNA, modified by incorporation of Zn2+ cations. We study the relative stability of different binding sites for the metal ions as well as different methods of charge neutralization. We find that binding the Zn cation to the N(7) atom of guanine or adenine leads always to lower energies than substitution of an imino proton between two H-bonded bases. Also, neutralizing with OH- groups bonded to Zn2+ is more stable than removing protons from the phosphate groups. Contrarily to common wisdom, we find that planarity of the base pairs is not an essential factor of stability, and that nonplanar base pairs can also be stacked effectively. Finally, we find that the most stable CG and AT helices, with Zn2+ bonded to N(7) atoms and neutralized by OH- ions, have wide band gaps of more than 2 eV, and we conclude that they are poor candidates for electronic conduction.

【 授权许可】

Free