title: Theoretical study on the binding mechanism between N6-methyladenine and natural DNA bases.
abstract: N6-methyladenine (m(6)A) is a rare base naturally occurring in DNA. It is different from the base adenine due to its N-CH(3). Therefore, the base not only pairs with thymine, but also with other DNA bases (cytosine, adenine and guanine). In this work, Møller-Plesset second-order (MP2) method has been used to investigate the binding mechanism between m(6)A and natural DNA bases in gas phase and in aqueous solution. The results show that N-CH(3) changed the way of N6-methyladenine binding to natural DNA bases. The binding style significantly influences the stability of base pairs. The trans-m(6)A:G and trans-m(6)A:C conformers are the most stable among all the base pairs. The existence of solvent can remarkably reduce the stability of the base pairs, and the DNA bases prefer pairing with trans-m(6)A to cis-m(6)A. Besides, the properties of these hydrogen bonds have been analyzed by atom in molecules (AIM) theory, natural bond orbital (NBO) analysis and Wiberg bond indexes (WBI). In addition, pairing with m(6)A decreases the binding energies compared to the normal Watson-Crick base pairs, it may explain the instability of the N6 site methylated DNA in theory.
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Qi-Xia
authors.initials: QX
authors.lastname: Song
authors.forename: Zhen-Dong
authors.initials: ZD
authors.lastname: Ding
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Hai-Jun
authors.initials: HJ
authors.lastname: Wang
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D020029:Base Pairing; D003596:Cytosine / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry; D006147:Guanine / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D013816:Thermodynamics
chemical_list: D000225:Adenine; D003596:Cytosine; D004247:DNA; D006147:Guanine; C000730567:6-methyladenine