Premium
Interaction and protection mechanism between li@C 60 and nucleic acid bases (NABs): Performance of PM6‐DH2 on noncovalent interaction of NABs‐Li@C60
Author(s) -
Sun Wenming,
Bu Yuxiang,
Wang Yixuan
Publication year - 2011
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.22881
Subject(s) - guanine , chemistry , dna , thymine , moiety , cytosine , stereochemistry , nucleic acid , binding energy , non covalent interactions , nucleotide , biochemistry , hydrogen bond , molecule , physics , organic chemistry , nuclear physics , gene
Abstract To discuss the protection mechanism of DNA from radiation as well as assess the performance of PM6‐DH2 on noncovalent interactions, the interaction of four nucleic acid bases (NABs) such as adenine (A), cytosine (C), guanine (G), and thymine (T), with Li@C 60 was extensively investigated with the‐state‐of‐art theoretical methods describing noncovalent systems, like M06‐2x, PBE‐D, and PM6‐DH2 methods. In the gas phase, the binding strength of NABs to Li@C 60 from M06‐2x decreases in the sequence, G>C>A>T. As dispersion was explicitly included, PBE‐D relatively enhances the binding of A and T and corrects the sequence to, G>A>C∼T. PM6‐DH2 predicted similar binding energies to those from PBE‐D within 0.5 kcal/mol and the same binding sequence, suggesting that the PM6‐DH2 method is promising for nano‐scale systems. In the aqueous solution, binding of NABs‐Li@C 60 is considerably decreased, and the M06‐2X and PM6‐D methods yield a different sequence from the gas phase, G>A>T>C. The encapsulation of Li atom results in a lower IP for Li@C 60 than those of NABs, and the dominant localization of single‐occupied molecular orbital on Li@C 60 moiety of the complexes NABs‐Li@C 60 further indicates that an electron would be ejected from Li@C 60 upon radiation and Li@C 60 is therefore able to protect DNA bases from radiation. In addition, it was revealed that Li prefers coordination with the hexagonal ring at Li@C 60 , which clarifies the existing controversy in this respect. Finally, Yang's reduced density gradient approach clearly shows that the weak and strong noncovalent interaction regions in the complexes, NABs‐Li@C 60 and (NABs‐Li@C 60 ) + . © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011