DNA replication,repair and recombination must depend on the interaction with the protein.N-methylacetamide(NMA) is one of the typical units in protein.Taking NMA and the bases in DNA as the stu-died objects,the interaction properties including geometry,charge distribution and binding energy of these NMA-base complexes were investigated in terms of the ABEEMσπ/MM method and the ab initio MP2 method.The geometry optimizations were performed at the B3LYP/6-311++G(d,p) level.The results of ABEEMσπ/MM and ab ini...