DNA3′,5′-磷酸二酯键骨架结构稳定的热力学基础分析

为了解大自然选择3′,5′-磷酸二酯键作为DNA结构骨架的必然性,从热力学角度模拟和计算了磷酸、2′-脱氧核糖、胞嘧啶及它们在不同位置结合形成的磷酸-2′-脱氧核糖、胞嘧啶-2′-脱氧核糖、磷酸-2′-脱氧核糖-胞嘧啶的能量,发现3′-磷酸-2′-脱氧核糖、5′-磷酸-2′-脱氧核糖、1′(-4-胞嘧啶)-2′-脱氧核糖、3′-磷酸-1′(-4-胞嘧啶)-2′-脱氧核糖、5′-磷酸-1′(-4-胞嘧啶)-2′-脱氧核糖的能量比其他相应形式结合物的能量低.表明磷酸与2′-脱氧核糖形成的3′,5′-磷酸二酯键有作为DNA结构骨架的热力学依据.

Analyse on the Thermodynamical Basis of 3', 5'-Phosphodiester Linkage to Structural Stability of DNA

To understand why 3′,5′-phosphodiester bond is ultimately chosen by the nature as the DNA structural framework,in this article,the energy of the phosphoric acid,2′-ribodesose,cytosine,as well as their compounds phosphoric acid-2′-ribodesose,2′-ribodesose-cytosine and phosphoric acid-2′-ribodesose-cytosine were calculated following thermodynamic method.It was found that the energy of 3′-deoxynucleotide,5′-deoxynucleotide,1′-deoxycytidine mono-phosphate,1′,3′-cytidine monophosphate,1′,5′-cytidine monophosphate is lower than that of the other resembling and non-resembling compounds,implying that there is a thermodynamical reason that the hydroxyl groups on the 2′-deoxyribose link to the phosphate groups to form DNA backbone.