Cd(Ⅱ)和ATP的结合位点的NMR研究

用NMR方法研究了金属镉离子在ATP(嘌呤三磷酸腺苷)上的配位点.测量了不同pH值时由于Cd²⁺的存在而引起的¹H,¹⁵N及³¹P的化学位移和³¹P－³¹P中的偶合常数的变化以及由ATP的存在所引起的¹¹³Cd的化学位移的变化.结果表明,在pH＞4.5的条件下,ATP主要以磷酸根和N₇同时对Cd²⁺配位;在pH值2.5～4.5的条件下,ATP主要以磷酸根和N₁同时对Cd²⁺配位,还存在少量的磷酸根和N₇同时配位的模式;而在酸性非常强的条件下(pH＜2.5),ATP不再与Cd²⁺相互作用。

NMR Study of ATP Binding Site with Cd2+

In this paper, the binding site of Cd²⁺ at the purine ring of ATPwas studied by using NMRtechnique.The changes of :H, 15Nand 31Pchemical shifts and 31P-31Pcoupling constants due to the presence of Cd²⁺ and the change of ¹¹³Cd chemical shift due to the presence of ATPin a wide pHrange are measured.It is found that, when pH>4.5, ATPchelates Cd²⁺ with its phosphate and N7; at pH 2.5-4.5, ATP binding sites are mainly phosphate and Nl, but phosphate/N7 mode still exists; when pHis very low (pH<2.5), ATPdoes not interact with Cd²⁺.