Highly selective binding of organometallic ruthenium ethylenediamine complexes to nucleic acids: Novel recognition mechanisms
Highly selective binding of organometallic ruthenium ethylenediamine complexes to nucleic acids: Novel recognition mechanisms
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DOI：
10.1021/ja027719m
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发表时间：
2003-01-08
影响因子：
15
通讯作者：
Sadler, PJ
中科院分区：
文献类型：
--
作者：
Chen, HM;Parkinson, JA;Sadler, PJ
我们研究了 [(eta(6)-arene)Ru(II)(en)X] 类型的有机金属钌 (II) 芳烃抗癌复合物对核酸衍生物的识别，其中 en = 乙二胺，芳烃 = 联苯 (Bip)、四氢蒽 (THA)、二氢蒽 (DHA)、对伞花烃 (Cym) 或苯 (Ben)，X = Cl- 或 H2O使用 H-1、P-31 和 N-15 (N-15-en) NMR 光谱。对于单核苷，{(eta(6)-Bip)Ru(en)}(2+)仅与鸟苷的N7、肌苷的N7和N1以及胸苷的N3结合。与胞苷N3的结合很弱，并且几乎没有观察到与腺苷的结合。在中性 pH 下，核碱基对 Ru 的各个结合位点的反应性按 G(N7) > I(N7) > I(NI)、T(N3) > C(N3) > A(N7)、A(N1) 的顺序降低。因此，伪八面体二氨基 Ru(II) 芳烃配合物在 G 和 A 碱基之间的辨别力比方形平面 Pt(II) 配合物高得多。这种位点选择性似乎是由 en NH2 基团控制的，该基团与环外氧形成氢键，但对核碱基的环外氨基不成键且具有排斥性。对于与单核苷酸的反应，观察到相同的位点选择性模式，但此外，在 5'-TMP、5'-CMP 和 5'-AMP 的平衡状态下存在大量 5'-磷酸盐结合物质 (40-60%)。相反，未检测到与 3'、5'-环 GMP (cGMP) 或 CAMP 的磷酸二酯基团的结合。与核苷酸的反应通过 [(eta(6)-芳烃)Ru(en)Cl](+) 的水化进行，然后快速结合到 5'-磷酸，然后重排以产生 N7、N1 或 N3 结合产物。还检测到少量双核物质，例如 Ru-O(PO3)GMPN7-Ru、Ru-O(PO3)IMPN1-Ru、Ru-O(PO3)TMP N3-Ru、Ru-N7IMP N1-Ru 和 Ru-N7InoN1-Ru。在 [(eta(6) -Bip)Ru(en)Cl](+) 与 5'-GMP 与 5'-AMP 或 5'-CMP 或 5'-TMP 的竞争性结合实验中，唯一的最终加合物是 [(eta(6)-Bip)Ru(en)(N7-GMP)]。 Ru-H2O 物种比 Ru-OH 物种更具反应性。中性溶液中 Cl- 或磷酸盐的存在通过与 Ru 的竞争性配位显着降低了 Ru-N7 的结合率。在动力学研究中（pH 7.0、298 K、100 mM NaClO4），cGMP 与 {(eta(6)-芳烃)Ru(II)(en)X}(n+) (X = Cl- 或 H2O) 的反应速率按顺序降低：THA > Bip > DHA >> Cym > Ben，表明缔合过渡态中有利的芳烃-嘌呤疏水相互作用促进了 N7 结合。这些发现揭示了二胺NH2基团、疏水芳烃和氯离去基团在Ru芳烃复合物识别核酸的新机制中具有重要作用，并将有助于设计更有效的抗癌复合物以及新的位点特异性DNA试剂。
We have investigated the recognition of nucleic acid derivatives by organometallic ruthenium(II) arene anticancer complexes of the type [(eta(6)-arene)Ru(II)(en)X] where en = ethylenediamine, arene = biphenyl (Bip), tetrahydroanthracene (THA), dihydroanthracene (DHA), p-cymene (Cym) or benzene (Ben), X = Cl- or H2O using H-1, P-31 and N-15 (N-15-en) NMR spectroscopy. For mononucleosides, {(eta(6)-Bip)Ru(en)}(2+) binds only to N7 of guanosine, to N7 and N1 of inosine, and to N3 of thymidine. Binding to N3 of cytidine was weak, and almost no binding to adenosine was observed. The reactivity of the various binding sites of nucleobases toward Ru at neutral pH decreased in the order G(N7) > I(N7) > I(NI), T(N3) > C(N3) > A(N7), A(N1). Therefore, pseudo-octahedral diamino Ru(II) arene complexes are much more highly discriminatory between G and A bases than square-planar Pt(II) complexes. Such site-selectivity appears to be controlled by the en NH2 groups, which H-bond with exocyclic oxygens but are nonbonding and repulsive toward exocyclic amino groups of the nucleobases. For reactions with mononucleotides, the same pattern of site selectivity was observed, but, in addition, significant amounts of the 5'-phosphate-bound species (40-60%) were present at equilibrium for 5'-TMP, 5'-CMP and 5'-AMP. In contrast, no binding to the phosphodiester groups of 3', 5'-cyclic-GMP (cGMP) or CAMP was detected. Reactions with nucleotides proceeded via aquation of [(eta(6)-arene)Ru(en)Cl](+), followed by rapid binding to the 5'-phosphate, and then rearrangement to give N7, N1, or N3-bound products. Small amounts of the dinuclear species, e.g., Ru-O(PO3)GMPN7-Ru, Ru-O(PO3)IMPN1-Ru, Ru-O(PO3)TMP N3-Ru, Ru-N7IMP N1-Ru, and Ru-N7InoN1-Ru were also detected. In competitive binding experiments for [(eta(6) -Bip)Ru(en)Cl](+) with 5'-GMP versus 5'-AMP or 5'-CMP or 5'-TMP, the only final adduct was [(eta(6)-Bip)Ru(en)(N7-GMP)]. Ru-H2O species were more reactive than Ru-OH species. The presence of Cl- or phosphate in neutral solution significantly decreased the rates of Ru-N7 binding through competitive coordination to Ru. In kinetic studies (pH 7.0, 298 K, 100 mM NaClO4), the rates of reaction of cGMP with {(eta(6)-arene)Ru(II)(en)X}(n+) (X = Cl- or H2O) decreased in the order: THA > Bip > DHA >> Cym > Ben, suggesting that N7-binding is promoted by favorable arene-purine hydrophobic interactions in the associative transition state. These findings have revealed that the diamine NH2 groups, the hydrophobic arene, and the chloride leaving group have important roles in the novel mechanism of recognition of nucleic acids by Ru arene complexes, and will aid the design of more effective anticancer complexes, as well as new site-specific DNA reagents.