生物无机化学翻译

1. Introduction

The interaction of transition metal complexes with nucleic acids has been one of the most vibrant areas of bioinorganic chemistry be-cause nucleic acids represent very important potential targets of can-cer diagnostic and chemotherapy drugs. Among the metal complexes studied in this context, ruthenium(II) complexes have attracted par-ticular interest as DNA structural probes, DNA footprinting reagents, DNA sequence-speci fi c cleaving agents, antitumor drugs and so on [1–7],owing to their rich photochemical, photophysical and redox properties. Much work pertaining to the RNA binding properties [8–11],RNA structural probes[12,13],and RNA binding pertinent anti-HIV (Human Immunode fi ciency Virus) activity of ruthenium(II) complexes [14–16]has also been reported, but the RNA binding prop-erties of ruthenium(II) complexes remain rather fragmentary as com-pared to their DNA binding studies. In order to deeply understand the RNA binding properties, and provide important fundamental data for RNA-targeting drugs, more work is required.

Calf thymus DNA (ct-DNA) differs from RNA not only in the compo-sition of bases but also in structure. The ct-DNA is B-form double-helical con fi guration with a wide major groove and relatively narrow minor groove, while yeast tRNA has an A-form con fi guration with L-shaped tertiary structure (mainly unispiral), and a deep and wide shallow minor groove. These differences would probably lead to different bind-ing 1.简介

过渡金属配合物与核酸的相互作用已经成为生物无机化学的最具活力的地区进行，导致核酸代表了CAN-CER诊断和化疗药物非常重要的潜在目标之一。在所研究在这方面的金属络合物，钌（II）配合物已经引起同水准满足特殊兴趣的DNA结构的探针，DNA足迹试剂，DNA 序列特异性断裂剂，抗肿瘤药物等[1-7]，由于它们的丰富的光化学，光物理和氧化还原特性。有关的RNA结合性质[8-11]许多工作，RNA 结构的探针[12,13]，以及RNA结合相关的抗HIV（人免疫缺陷病毒）钌的活性（II）的配合物[14-16]也已经的报道，但该RNA结合丙ERTIES 钌（II）配合保持，而局部作为COM-相比于它们的DNA结合研究。为了深入了解RNA绑定属性，并为RNA靶向药物的重要基础数据，更多的工作是必需的。

小牛胸腺DNA（小牛胸腺DNA）不同于RNA不仅在COMPO-习得的碱基，而且在结构。的小牛胸腺DNA是具有宽大沟和相对窄的小沟B型双螺旋结构，而酵母tRNA具有L形的三级结构（主要unispiral）的A-形式配置，并且一个又深又宽浅次要槽。这些差异可能会导致不同的绑定，荷兰国际集团模式和亲和力[17]。这些启发我们进行比较研究上的钌（II）配合物的DNA和RNA的相互作用。我们的研究小组发现，使用[Ru（联吡啶）（IIP）2] 2+ {IIP=2-（1H-吲哚-3-基）-1H-咪唑并[4,5-f]的1,10-菲咯啉}[11]更牢固地结合到RNA的比对的DNA，与此相反的行为

[(bpy)2Ru(ebipc)Ru(bpy)2]4+{ebipc=N-ethyl-4,7-bis(imidazolo[4,5-f]-(1,10-phenanthrolin)-2-yl-)carbazole} [9]。

由于顺铂被批准用于睾丸和卵巢的使用可以-核证减排量在1978年由美国食品和药物管理局，金属为基础的癌症化疗药物的发展吸引了显-着关注。作为替代候选顺铂，钌系分子已经成为有希望的化学治疗药物的铂- 耐药性肿瘤[18,19]。例如，咪唑鎓反式imidazoledimethylsulfoxidetetrachlororuthenate显示针对转移非常高的活性，尽管它不显示戏剧性cytotox-孵化城在肿瘤细胞系的体外[18,19]。由于它们的可逆的氧化还原性质，良好的细胞渗透性和稳定性在生物水溶液，有氧媒体，二茂铁及其衍生物也备受关注为bioorganometallic抗癌药物[20-23]。例如，二茂铁部分中ferrocifen，这是一个二茂铁共轭TA-moxifen，显着增强了他莫昔芬[20]的抗癌活性。因此，可以推断，二茂铁基的钌络合物附件可能得到新的

modes and af fi nities [17]. These inspired us to conduct comparative studies on the interaction of ruthenium(II) complexes with the DNA and the RNA. Our group found that [Ru(bpy)(iip)2]2 +{iip = 2-(1H-indole-3-yl)-1H-imidazo[4,5-f]1,10-phenanthrolin e} [11]more strongly bound to the RNA than to the DNA, in contrast to the behavior of [(bpy)2Ru(ebipc)Ru(bpy)2]4+{ebipc=N-ethyl-4,7-bis(imid azolo[4,5-f]-(1,10-phenanthrolin)-2-yl-)carbazole} [9].

Since Cisplatin was approved for use in testicular and ovarian can-cers by the U.S. Food and Drug Administration in 1978, the development of metal-based cancer chemotherapeutic agents has attracted signi fi-cant attention. As alternative candidates to Cisplatin, ruthenium-based molecules have emerged as promising chemotherapeutic drugs of platinum-resistant tumors [18,19]. For example, imidazolium

trans-imidazoledimethylsulfoxidetetrachlororuthenate displays a very high activity against metastases although it does not show dramatic cytotox-icity in tumor cell lines in vitro [18,19]. Owing to their reversible redox property, good cell permeability, and stability in biological aqueous, aerobic media, ferrocene and its derivatives have also attracted much attention for bioorganometallic anticancer drugs [20–23]. For instance, the ferrocenyl moiety in ferrocifen, which is a ferrocene-conjugated ta-moxifen, remarkably augments the anticancer activity of tamoxifen [20].Therefore, it can be inferred that the attachment of ferrocenyl group metallodrugs具有更好的化疗效果。另外，对于脱velopment metallodrugs作为光动力剂的一个重要标准是它们photocleave DNA的能力。钌（II）的大量复合物已被发现显示有趣的光敏DNA断裂[24-30]，或金属激活水解切割[31-33]。一些二茂阳离子盐已发现由Osella和同事显示oxida-略去DNA损伤[34]。上述令人振奋的结果促使我们进行研究的DNA- [35]和RNA结合的pUC和DNA 18光切割一个多吡啶钌和氧化还原活性二茂铁基部分含二茂铁基，[茹（联吡啶）2（FIP的性质）]（PF 6）2 {FIP = 2二茂铁基-1H-咪唑并[4,5-f]的[1,10] PHE-nanthroline}（参见方案1的分子结构），被发现前hibit增强DNA切割效率相比，二茂铁- 自由类似物的[Ru（联吡啶）2（PIP）] 2 + {点子= 2-苯基-1H-咪唑并[4,5-f]的[1,10]菲咯啉}。

2.实验部分

材料，仪器仪表，以及用于分光MEA-surements，核酸结合研究和理论计算方法示于补充材料。光诱导DNA cleav年龄为[茹（联吡啶）2（FIP）]2+和[茹（联吡啶）2（IP）] 2+进行了检查，琼脂糖凝胶电泳。超螺旋的pUC18的DNA（0.2微克）与的Tris-HCl液（Tris=三（羟甲基）氨基甲烷）缓冲液（50mM三- 盐酸，18 mM氯化钠，pH值= 7.2）的复合物进行处理，该溶液然后在室温照射温度用UV光（360纳米，8毫瓦厘米-2），用于在黑暗中孵育1小时，1小时后。将样品通过电泳在80 V 于0.8％琼脂糖凝胶在缓冲液1小时（40毫摩尔Tris-CH 3 COOH，1mM EDTA中，pH值= 8.0）进行分析。将凝胶用1μg的ML-1溴化乙锭（EB）和在UV光下拍照。裂解的（C）的比例是根据公式计算的。（1）：凡DI，DII和DIII分别是I型（超螺旋形式），II型（切口形式）和III 型（线性表），综合密度值。

4.结论

这项工作表明，钌（II）络合物的DNA结合和光切割性能被显著通过附加二茂铁基团与母体复杂的[Ru（联吡啶）2（IP）]（ClO4）2的改善。的光谱研究和粘度测量用sug-gested那的插入一个含二茂铁络合物的[Ru（联吡啶）2（FIP）]（PF 6）2到DNA是具有结合亲和性的DNA {KB =主导装订模式（5.37±0.35）×105 M-1}大于至RNA {KB =（2.16±0.23）×105 M-1}，虽然一个沟结合模式可与插层共存所揭示的电子束的COM-请愿实验。的密度泛函理论calcula-系统蒸发散的结果表明，使用[Ru（联吡啶）2（FIP）]（PF 6）2相对于所述二茂铁基无父络合物的[Ru （联吡啶）2（IP的增强的DNA结合亲和力）]（PF 6）2是由于FIP主

to ruthenium complexes may obtain novel metallodrugs with better chemotherapeutic effects. Also, an important criterion for the de-velopment of metallodrugs as photodynamic agents is their ability to photocleave DNA. A great many of ruthenium(II) complexes have been found to show interesting photoactivated DNA cleavage [24–30], or the metal-activated hydrolytic cleavage [31–33]. Some ferrocenium cationic salts have been found by Osella and co-workers to show oxida-tive DNA damage [34]. Above-mentioned exciting results prompted us to conduct the studies on the DNA- [35] and RNA-binding and pUC 18 DNA photocleavage properties of a ferrocenyl-containing ruthenium (II) complex. As anticipated, the metal complex consisting of the photo-active ruthenium polypyridyl and redox-active ferrocenyl moieties, [Ru(bpy)2(fip)](PF6)2 {fip = 2-ferrocenyl-1H-imidazo[4,5-f][1,10]phe-nanthroline} (see Scheme 1 for molecular structure), was found to ex-hibit enhanced DNA cleavage efficiency compared to a ferrocene-free analogue [Ru(bpy)2(pip)]2 + {pip = 2-phenyl-1H-imidazo[4,5-f] [1,10]phenanthroline}.

2. Experimental section

Materials, instrumentations, and methods for spectroscopic mea-surements, nucleic acid binding studies and theoretical calculations are shown in the Supplementary materials. Photoinduced DNA

cleav-age by [Ru(bpy)2(fi p)]2 +and [Ru(bpy)2(ip)]2 + was examined by Agarose gel electrophoresis. Supercoiled pUC 18 DNA (0.2 μg) was treated with the complexes in Tris–HCl (Tris = tris(hydroxymethyl) aminomethane) buffer (50 mM Tris- HCl, 18 mM NaCl, pH = 7.2) and the solution was then irradiated at room temperature with UV light (360 nm, 8 mW cm?2) for 1 h after incubation in the dark for 1 h. The samples were analyzed by electrophoresis for 1 h at 80 V on a 0.8% agarose gel in buffer (40 mM Tris–CH3COOH, 1 mM EDTA, pH = 8.0). The gel was stained with 1 μg mL?1 ethidium bromide (EB) and photographed under UV 配体，而不是局部的FIP和ip LUMOS（L + 2，L + 3）的人口和能量的电子因素的较大偶联平面。当IRRA-diated在360纳米，[茹（联吡啶）2（FIP）]（PF 6）2被发现photocleave的pUC 18 DNA非常有效地切割效率3-4倍一样大，二茂铁基的免费模拟[茹（联吡啶）2（PIP）]（ClO4）2的相同的实验条件下。单线态氧，氢氧自由基和超氧化物-IDE阴离子自由基被发现同时参加的DNA裂解工艺效果。这项研究将提供基本的实验数据，光动力治疗癌症的潜在光敏剂的发展。

light. The percentage of cleavage (C) was calculated according to Eq. (1):

Where D I, D II and D III are the integrated density values of Form I (supercoil form), Form II (nicking form) and Form III (linear form), respectively.

4. Conclusion

This work demonstrated that the DNA-binding and photocleavage-properties of the Ru(II) complex were signi fi cantly improved by appending the ferrocenyl group to the parent complex [Ru(bpy)2(ip)] (ClO4)2. The spectroscopic studies and viscosity measurements sug-gested that the intercalation of a ferrocenyl-containing complex [Ru (bpy)2(fi p)](PF6)2 into the DNA is the dominant binding mode with binding af fi nity to the DNA {K b= (5.37 ± 0.35) × 105M?1} greater than to the RNA {K b= (2.16 ± 0.23) × 105 M?1}, although a groove binding mode may coexist with the intercalation as revealed by EB com-petition experiment. The results of density-functional theory calcula-tions showed that the enhanced DNA binding af fi nity of [Ru(bpy)2(fi p)](PF6)2relative to that of the ferrocenyl-free parent complex [Ru(bpy)2(ip)](PF6)2is due to the larger conjugation plane of the main ligand of fi p rather than the electronic factors of the populations and energies of LUMOs (L+ 2, L + 3) localized on fi p and ip. When irra-diated at 360 nm, [Ru(bpy)2(fi p)](PF6)2 was found to photocleave pUC 18 DNA very ef fi ciently with cleavage ef fi ciency 3–4 times as great as ferrocenyl group-free analog [Ru(bpy)2(pip)](ClO4)2under the same experimental conditions. Singlet oxygen, hydroxyl radical and superox-ide anion radical were found to take effect simultaneously in the DNA cleavage process. This

study would provide fundamental experimental data for development of potential photosensitisers for photodynamic cancer therapy.