Chemistry M313, School of Biomedical, Biomolecular & Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
Chemistry. 2009 Sep 21;15(37):9365-74. doi: 10.1002/chem.200900958.
Reported herein is a study of the unusual 3'-3' 1,4-GG interstrand cross-link (IXL) formation in duplex DNA by a series of polynuclear platinum anticancer complexes. To examine the effect of possible preassociation through charge and hydrogen-bonding effects the closely related compounds {trans-PtCl(NH(3))(2)}(2)(mu-trans-Pt(NH(3))(2){NH(2)(CH(2))(6)NH(2)}(2)) (BBR3464, 1), {trans-PtCl(NH(3))(2)}(2)(mu-NH(2)(CH(2))(6)NH(2)) (BBR3005, 2), {trans-PtCl(NH(3))(2)}(2)(mu-H(2)N(CH(2))(3)NH(2)(CH(2))(4)) (BBR3571, 3) and {trans-PtCl(NH(3))(2)}(2){mu-H(2)N(CH(2))(3)-N(COCF(3))(CH(2))(4)} (BBR3571-COCF(3), 4) were studied. Two different molecular biology approaches were used to investigate the effect of DNA template upon IXL formation in synthetic 20-base-pair duplexes. In the "hybridisation directed" method the monofunctionally adducted top strands were hybridised with their complementary 5'-end labelled strands; after 24 h the efficiency of interstrand cross-linking in the 5'-5' direction was slightly higher than in the 3'-3' direction. The second method involved "postsynthetic modification" of the intact duplex; significantly less cross-linking was observed, but again a slight preference for the 5'-5' duplex was present. 2D [(1)H, (15)N] HSQC NMR spectroscopy studies of the reaction of [(15)N]-1 with the sequence 5'-d{TATACATGTATA}(2) allowed direct comparison of the stepwise formation of the 3'-3' IXL with the previously studied 5'-5' IXL on the analogous sequence 5'-d(ATATGTACATAT)(2). Whereas the preassociation and aquation steps were similar, differences were evident at the monofunctional binding step. The reaction did not yield a single distinct 3'-3' 1,4-GG IXL, but numerous cross-linked adducts formed. Similar results were found for the reaction with the dinuclear [(15)N]-2. Molecular dynamics simulations for the 3'-3' IXLs formed by both 1 and 2 showed a highly distorted structure with evident fraying of the end base pairs and considerable widening of the minor groove.
本文报道了一系列多核铂类抗癌配合物在双链 DNA 中形成异常的 3'-3' 1,4-GG 链间交联 (IXL)。为了研究通过电荷和氢键作用可能发生的预结合的影响，研究了密切相关的化合物 {trans-PtCl(NH(3))(2)}(2)(mu-trans-Pt(NH(3))(2){NH(2)(CH(2))(6)NH(2)}(2)) (BBR3464, 1)、{trans-PtCl(NH(3))(2)}(2)(mu-NH(2)(CH(2))(6)NH(2)) (BBR3005, 2)、{trans-PtCl(NH(3))(2)}(2)(mu-H(2)N(CH(2))(3)NH(2)(CH(2))(4)) (BBR3571, 3) 和 {trans-PtCl(NH(3))(2)}(2){mu-H(2)N(CH(2))(3)-N(COCF(3))(CH(2))(4)} (BBR3571-COCF(3), 4)。使用两种不同的分子生物学方法研究了 DNA 模板对合成 20 碱基对双链体中 IXL 形成的影响。在“杂交导向”方法中，单功能加合物的顶部链与它们互补的 5'-端标记链杂交；24 小时后，5'-5'方向的链间交联效率略高于 3'-3'方向。第二种方法涉及完整双链体的“合成后修饰”；观察到的交联明显较少，但仍然存在对 5'-5'双链体的轻微偏好。对 [(15)N]-1 与序列 5'-d{TATACATGTATA}(2)的反应的 2D [(1)H, (15)N] HSQC NMR 光谱研究允许直接比较在类似序列 5'-d(ATATGTACATAT)(2)上先前研究的 5'-5' IXL 与逐步形成的 3'-3' IXL。尽管预结合和水合步骤相似，但在单功能结合步骤中存在差异。该反应没有产生单一明显的 3'-3' 1,4-GG IXL，而是形成了许多交联加合物。与双核 [(15)N]-2 的反应得到了类似的结果。通过 1 和 2 形成的 3'-3' IXL 的分子动力学模拟显示出高度扭曲的结构，末端碱基对明显磨损，小沟明显变宽。
