手性三菲咯啉合镍与DNA的立体选择性研究

有关 DNA与金属配合物反应机理和作用模式的探讨是生物无机化学研究的重要内容之一 .目前的研究 [1～ 4] 表明 ,有大共轭配体配位的八面体金属配合物以静电作用或插入方式与DNA结合 .外消旋 [Ni( phen) 3]2 +及其旋光异构体与 DNA作用机理的研究曾有报道 [4] .但用电化学方法研究其旋光异构体与 DNA作用则未见详细报道 .本文用电化学方法和 CD谱研究了 Δ- ,∧ - [Ni( phen) 3]2 +配合物与 DNA的作用 .两种方法所得结果均表明 Δ- ,∧ - [Ni( phen) 3]2 +与 DNA作用时 ,Δ构型配合物的插入作用比∧构型配合物的强 .该法与平衡透析…     

二价金属离子对鲑鱼精DNA热稳定性的影响

二价金属离子与 DNA之间的作用在 DNA复制、转录以及新陈代谢过程中起到重要的作用 ,因此越来越受到关注 [1,2 ] .L uck等 [3 ]指出 ,碱土金属与 DNA分子的磷酸基团发生作用使 DNA的热稳定性升高 ,而二价过渡金属离子主要是与碱基作用而使 DNA热稳定性降低 . Eichhorn等 [4 ] 用变温紫外光谱法研究了在 DNA磷酸根离子的浓度较小 (0～ 4.0 )时 ,多种二价金属离子对小牛胸腺 DNA热稳定性的影响 ,发现 Mg2 + 及过渡金属离子 Mn2 + ,Co2 + 和 Ni2 + 都有利于 DNA的稳定 .最近 ,Duguid等 [5]用差示扫描量热法 (DSC)研究了在 c(M2 +…     

生物医学中DNA的结构、构象、作用机制及其生物功能的研究进展

针对国际上目前对小分子多吡啶配合物研究大分子DNA的结构和作用机制等的争论焦点,用荧光淬灭实验证明DNA是一根分子导线的假设,系统地介绍了小分子多吡啶配合物和大分子DNA作用的影响因素.从CD光谱首次观察到和-[Ru(bpy)₂HPIP]²⁺异构体以不同速度插入到小牛胸腺DNA中.此外,对多吡啶配合物在DNA中的生物功能也作了简要介绍.     

新型双核配合物的形成及荧光性质研究

利用光谱学方法研究了[Ru(bpy)2TPPHZ]2+(TPPHZ=四吡啶[3,2-a: 2',3'-c: 3",2"-h: 2'",3'"-j]吩嗪)和[Ru(bpy)2ODHIP]2+(ODHIP=3,4-二羟基-咪唑并[4,5-f][1,10]邻菲咯啉)与Ni2+的配位情况及配位后的荧光性质变化, 探讨了配合物与Ni2+配位形成双核配合物后与DNA的作用机制变化. 结果表明, [Ru(bpy)2TPPHZ]2+和[Ru(bpy)2ODHIP]2+均可与Ni2+配位, 形成双核配合物[Ru(bpy)2(TPPHZ)Ni]4+和[Ru(bpy)2(ODHIP)Ni]4+, 配合物的荧光强度随着Ni2+浓度的增加而减弱. 与DNA作用后, 配合物仍可与Ni2+配位形成双核配合物, [Ru(bpy)2(TPPHZ)Ni]4+的荧光几乎完全消失, 同时配合物与DNA保持插入模式作用, 而配合物[Ru(bpy)2(ODHIP)Ni]4+与DNA的作用则由沟面结合改为插入结合, 同时配合物的荧光减弱.     

钌(Ⅱ)多吡啶配合物与DNA相互作用的光切割与荧光性质研究

利用琼脂糖凝胶电泳法研究了钌(Ⅱ)多吡啶配位物[Ru(bpy)2(ODCIP)]2+(bpy:2,2'-联吡啶,ODCIP:含多个配位中心的多吡啶配体,3,4-二氯基-咪唑并[4,5-f][1,10]邻菲咯啉)对pBR322质粒DNA的光切割作用及其可能机理,并运用紫外可见吸收光谱、荧光光谱和琼脂糖凝胶电泳法研究了[Ru(bpy)2(ODCIP)]2+与Zn2+配位后与DNA的光谱性质和光切割作用.结果表明[Ru(bpy)2(ODCIP)]2+对DNA有较好的光切割作用,其机理可能是产生了超氧阴离子自由基和单线态氧.[Ru(bpy)2(ODCIP)]2+与Zn2+配位可能形成的双核配位物[Ru(bpy)2(ODCIP)Zn]4+与DNA也能进行插入结合,对DNA的光切割效果并没有明显增强。     

新型含磷酰基的脂溶性自由基捕捉剂的合成及其ESR研究

超氧阴离子自由基的研究最近得到了广泛的关注 ,这主要是因为超氧阴离子自由基及由其诱导产生的各种活性氧 ( HOO· ,HO· 和 H2 O2 )与许多病理过程有关 ,如发炎 [1] 、缺血再灌综合症 [2 ] 、 DNA损伤[3] 和神经死亡疾病 [4 ] 等 .自旋捕捉技术是检测自由基最有效的方法 [5～ 9] ,近年来在生物体系活性氧自由基检测中得到广泛应用 [10 ,11] ,大力推动了生物自由基领域的研究 .合成新型自由基捕捉剂及改善其对超氧阴离子自由基的捕捉性能一直是人们追逐的热点 ,我们正致力于这方面的研究 [12 ] .其中提高自由基捕捉剂的脂溶性 ,扩大自…     

液体环境单分子免疫球蛋白G的原子力显微镜高分辨成像

原子力显微镜技术( AFM)具有纳米级高分辨成像能力,是研究生物大分子结构和功能的重要工具之一。制备合适的样品是获取高分辨成像的关键要素。本研究结合DNA折纸技术,将抗原分子修饰在DNA折纸上,通过分子识别作用,抗体分子与抗原分子特异性结合,形成由DNA折纸和抗原抗体复合物构成的纳米结构。利用DNA折纸在云母表面上的吸附特点,使得抗体分子选择性地吸附在衬底表面上,由此获得了液体环境中的单个地高辛抗体免疫球蛋白G( IgG)分子的“Y”超微结构形貌。本方法简单、方便,为AFM在单分子水平上检测和表征生物分子结构和功能提供帮助。     

利用DPN技术直接构建磁性纳米图形

在纳米尺度下构建有序的磁性模板和图形是当前的研究热点之一 [1,2 ] .这种模板在生物样品的分离[1] 、磁电子学研究和信息存储 [2 ] 等领域具有重要意义 .目前 ,光刻 [3] 、微触点印刷 [4 ] 和自组装 [5] 等多项技术已被用来构建各种纳米模板 .1 999年 ,美国西北大学 Mirkin小组 [6 ]发明的 Dip- pen纳米刻蚀技术 (简称 DPN技术 )更在可控组装方面显示出巨大优越性 .这项技术是在一定驱动力作用下 ,使吸附在原子力显微镜 ( AFM)针尖上的分子“墨水”逐渐转移到基底表面上 ,实现纳米模板的可控构建 .与传统技术相比 ,DPN技术可在纳米尺…     

PICA法制备用于高效液相色谱的锆胶基质柱填料

迄今 ,硅胶基质固定相在 HPLC领域仍占据主导地位 ,但由于它的 p H使用范围窄 ,尤其在碱性条件下基质逐渐溶解 ,其使用受到限制 [1] .为此 ,寻找稳定性能高的新基质成为当前色谱学研究的热点之一 ,二氧化锆因具有良好化学稳定性和机械强度而受到关注 .目前 ,制备微米级、球形和多孔二氧化锆基质柱填料的常用方法有两种 :(1 )油乳化法 (OEM) ;(2 )聚合诱导胶体凝聚法 (PICA) .OEM法操作简单 ,但制备的二氧化锆微球粒径分布宽且孔径较小 .Carr[2 ,3] ,Unger[4 ] ,Rassi[5,6 ]和 Kawahara等[7,8] 在用 OEM法制备二氧化锆微球方面做了…     

乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)2(dppz)]2+光致发光的调控

应用荧光光谱、荧光显微镜和伏安法研究了乙醇/水体系中Cu(Ⅱ)对十二烷基硫酸钠(SDS)和鱼精DNA增强[Ru(bpy)2(dppz)]2+(bpy=2,2′-联吡啶,dppz=邻联二吡啶[3,2-a:2′,3′-c]吩嗪)光致发光的调控。结果表明,在乙醇/三羟甲基氨基甲烷(Tris)-水(V乙醇∶VTris=1∶5)体系中,DNA和阴离子表面活性剂SDS均能增强[Ru(bpy)2(dppz)]2+的光致发光,其与[Ru(bpy)2(dppz)]2+间的键合常数分别为5.5×105和4.2×102L.mol-1;Cu(Ⅱ)离子能通过DNA和SDS介导的光诱导电子转移淬灭乙醇/水溶液中[Ru(bpy)2(dppz)]2+的光致发光,DNA介导的Stern-Volmer淬灭常数为2.0×105L.mol-1,远远大于SDS介导的淬灭常数(9.0×103L.mol-1)。此外,结合SDS、DNA和Cu(Ⅱ)对[Ru(bpy)2(dppz)]2+在铟锡氧化物(ITO)电极上发生的氧化还原反应的影响,进一步探讨了乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)2(dppz)]2+光致发光的调控机理。该研究有助于更好地理解DNA嵌入剂的发光和淬灭机制,为生物分子光开关的构建提供新思路。     

Exploring the interaction of ruthenium(II) polypyridyl complexes with DNA using single-molecule techniques

Here we explore DNA binding by a family of ruthenium(II) polypyridyl complexes using an atomic force microscope (AFM) and optical tweezers. We demonstrate using AFM that Ru(bpy)2dppz2+ intercalates into DNA (K(b) = 1.5 x 10(5) M(-1)), as does its close relative Ru(bpy)2dppx2+ (K(b) = 1.5 x 10(5) M(-1)). However, intercalation by Ru(phen)3(2+) and other Ru(II) complexes with K(b) values lower than that of Ru(bpy)2dppz2+ is difficult to determine using AFM because of competing aggregation and surface-binding phenomena. At the high Ru(II) concentrations required to evaluate intercalation, most of the DNA strands acquire a twisted, curled conformation that is impossible to measure accurately. The condensation of DNA on mica in the presence of polycations is well known, but it clearly precludes the accurate assessment by AFM of DNA intercalation by most Ru(II) complexes, though not by ethidium bromide and other monovalent intercalators. When stretching individual DNA molecules using optical tweezers, the same limitation on high metal concentration does not exist. Using optical tweezers, we show that Ru(phen)2dppz2+ intercalates avidly (K(b) = 3.2 x 10(6) M(-1)) whereas Ru(bpy)3(2+) does not intercalate, even at micromolar ruthenium concentrations. Ru(phen)3(2+) is shown to intercalate weakly (i.e., at micromolar concentrations (K(b) = 8.8 x 10(3) M(-1))). The distinct differences in DNA stretching behavior between Ru(phen)3(2+) and Ru(bpy)3(2+) clearly illustrate that intercalation can be distinguished from groove binding by pulling the DNA with optical tweezers. Our results demonstrate both the benefits and challenges of two single-molecule methods of exploring DNA binding and help to elucidate the mode of binding of Ru(phen)3(2+).     

Construction and control of plasmid DNA network

The influences of different cations on plasmid DNA network structures on a mica substrate were investigated by atomic force microscopy (AFM). Interactions between the DNA strands and mica substrate, and between the DNA strands themselves were more strongly influenced by the complex cations (Fe(phen)3(2+), Ni(phen)3(2+), and Co(phen)3(3+)) than by the simple cations (Mg2+, Mn2+, Ni2+, Ca2+, Co3+). The mesh height of the plasmid DNA network was higher when the complex cations were added to DNA samples. The mesh size decreased with increasing DNA concentration and increased with decreasing DNA concentration in the same cation solution sample. Hence, plasmid DNA network height can be controlled by selecting different cations, and the mesh size can be controlled by adjusting plasmid DNA concentration.     

荧光法研究手性金属配合物与DNA的作用机理

以溴化乙锭为荧光探针，研究手性金属配合物［Ｎｉ（ｐｈｅｎ）３］＾＋和［Ｆｅ（ｐｈｅｎ）３］＾２＋与ＤＮＡ的反应机理。结果表明，配合物与ＤＮＡ作用存在插入和静电结合两种模式，即部分菲咯啉配体插入ＤＮＡ双螺旋碱基对中，同时带正电荷的配合物与ＤＮＡ的磷酸基团发生静电结合。     

Comprehensive studies on the DNA-binding and cleavage properties of a nickel complex derived from phthalate and 1,10-phenanthroline

Binding properties of a nickel complex, [Ni(phen)(pha)(H₂O)₃] (phen = 1,10-phenanthroline, pha = o-phthalate) to DNA were comprehensively investigated by electronic absorption spectroscopy, viscosity, electrochemistry, melting temperature and gel electrophoresis measurements. After interaction with DNA, the hypochromism and bathochromism for the characteristic absorption peaks of [Ni(phen)(pha)(H₂O)₃] revealed a typical intercalation, which was proved by viscosity and melting temperature experiments. Electrochemical assays showed that the electrochemical activity of the nickel complex was shielded after inserting into the double-helix structure of DNA. Moreover, the results of agarose gel electrophoresis showed that the complex had moderate cleavage ability to supercoiled DNA in the presence of H₂O₂.     

A Novel Optical Properties of Molecular “Light Switch” and its Analytical Application

Because of the high affinity (Ka≥ 10^6 L mol^-1) between Ru(phen)2(dppz)^2 and DNA, the adding of DNA in the solution of Ru(phen)E(dppz)^2 -SDS makes the dissociation of Ru(phen)E(dppz)^2 -SDS, and results in decrease of the resonance light scattering (RLS) signals andincrease of the absorbance. Based on this, a novel method is proposed for DNA assay.     

A Self-assembled T4（2）5（2） Water Tape Stabilized by a Nickel（II） Complex with L-cysteic Acid

An interesting T4(2)5(2) water tape formed by fused cyclic water pentamers and tetramer was self-assembled in a new inorganic host [Ni(L)(phen)2]·5H2O (L = L-cysteic acid) and characterized by X-ray diffraction. Each [Ni(L)(phen)2] molecule crystallizes with five water molecules with a molecular formula of [Ni(L)(phen)2]·5H2O. The T4(2)5(2) water tape and [Ni(L)(phen)2] molecules assemble into a network of water tapes sandwiched between [Ni(L)- (phen)2] tapes. The network is stabilized by π-π stacking between [Ni(L)(phen)2] molecules and three types of hydrogen-bonding interactions between [Ni(L)(phen)2] molecules, water molecules, and water and [Ni(L)(phen)2] molecules.     

多巴胺在dsDNA/Ni2+/聚邻氨基酚修饰碳糊电极上的伏安行为

通过电化学聚合法在碳糊电极上共聚制备了聚邻氨基酚/Ni2+膜(Ni2+/P-OAP/CPE), 研究了膜的伏安特性, 并制成dsDNA修饰电极, 通过电化学和紫外光谱法进行表征. 将dsDNA/Ni2+/P-OAP/CPE电极应用于多巴胺的电催化氧化, 同时将该方法用于盐酸多巴胺针剂的测定, 亦获得了满意的结果.     

Crystal Structure and Spectroscopic Properties of[Ni（phen）3]Pic2.2CH3CN

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高氯酸化三邻菲啰啉合镍晶体结构研究

用Ni(ClO4)2合成了高氯酸阴离子和三邻菲啰啉合镍阳离子组成的盐晶体, 晶体结构由X射线衍射确定. 晶体属P21/n空间群, a=0.9388(2) nm, b=3.0139(5) nm, c=1.2974(2) nm, β=111.054(3)º, V=3.426(1) nm3. 采用hyperchem程序包的半经验方法ZINDO/1计算了该配合物的最优化结构, 原子电荷分布很好地佐证了晶体结构的配位环境.     

Synthesis,characterization, duplex-DNA interactions,and anticancer activities of novel octahedral [Ni(phen)2(dppz-idzo)]2+ and [Co(phen)2(dppz-idzo)]3+ complexes

Two new octahedral [Ni(phen)₂(dppz-idzo)]²⁺ and [Co(phen)₂(dppz-idzo)]³⁺ complexes have been synthesized and characterized by CHN analysis, electrospray ionization-MS, nuclear magnetic resonance, and UV–Vis spectra. The DNA-binding ability of these complexes was spectrophotometrically, hydrodynamically, and electrophoretically evaluated which indicated that they strongly intercalate into the DNA double helix, and that both induced severe DNA damage in the presence of peroxide. The complexes also showed strong antiproliferative effect against HepG2 and MDA-MB-231 cells. By contrast, they were found to be inactive against the MCF-7 cell line. The ligand itself was found to be inactive against the cells tested.