环三聚磷腈多齿配体的合成及DNA的切割活性

为了得到具有核酸切割功能的人工核酸酶, 设计合成了5种环三聚磷腈多齿配体, 并初步检测了其对DNA的切割活性. 目标化合物的结构由IR, 1H NMR, 31P NMR, 13C NMR和ESI-MS确认. 在生理条件下对pUC19 DNA切割活性的初步实验结果表明, 在化合物5a～5e的Cu(Ⅱ)配合物存在下, 保温24 h后, pUC19 DNA由Form Ⅰ断裂为Form Ⅱ, 即合成目标化合物有明显的DNA切割活性. 同时, 考察了配合物5b+Cu在不同时间下对DNA的切割活性的影响.     

新型有机小分子DNA切割试剂的合成

根据活性基团的协同催化原理,设计合成了有机小分子核酸切割剂1-(N-胍乙基)-4-(N-羟乙基)哌嗪盐酸盐(4),并通过核磁共振和液相色谱-质谱联用技术对其结构进行了表征.利用琼糖凝胶电泳研究了pH值对其切割pUC 19 DNA效率的影响,通过自由基猝灭实验研究其切割DNA的反应类型.运用密度泛函理论,利用Gaussian软件进行了理论计算,研究其裂解DNA的反应方式.研究结果表明,在pH=7.2时化合物4的裂解效率最高,且能通过非氧化还原反应以磷酯转移的方式裂解DNA的磷酸二酯键.     

紫精与八元瓜环的超分子组装及光切割质粒DNA

利用紫精可以活化水中溶解氧的特性, 设计合成了苯-紫精化合物(BEV). 利用紫外吸收、电化学及核磁等方法研究了BEV与八元瓜环CB[8] 之间的相互作用. 实验结果表明, 2种化合物可以进行主客体超分子自组装形成1∶ 1的二元包合物BEV-CB[8]. 同时, 分别考察了化合物BEV和BEV-CB[8]与小牛胸腺DNA的相互作用, 并采用琼脂糖凝胶电泳研究了氙灯光照下化合物对pBR322 DNA的切割能力. 结果表明, CB[8]的引入改变了化合物BEV与DNA的作用方式, 使嵌入作用和静电作用增强. 光照结果说明只有超分子BEV-CB[8]在光照下可以完全切割质粒DNA, 即CB[8]的存在明显提高了BEV对质粒DNA的切割效率.     

含氨基萘酰亚胺类DNA嵌入剂切割质粒DNA

合成了一系列含氨基的萘酰亚胺类化合物以开发新型的DNA切割剂。琼脂糖电泳分析表明,100μmol/L含氨基萘酰亚胺化合物在70℃、pH7·5的条件下能有效切割超螺旋质粒DNA,而且切割产物均为接近原质粒大小一半的DNA线性片段。     

具有DNA切割功能的新型多聚酰胺/丝组缀合物

为得到具有核酸切割功能的人工核酸酶, 设计合成了一种新型多聚酰胺/丝组缀合物, 并研究了其DNA切割活性. 合成的目标化合物在pH=6.0的BR缓冲溶液中对pBR322 DNA切割活性的初步实验结果表明, 于37 ℃保温6 h后, pBR322 DNA基本上被完全从Form Ⅰ切割为Form Ⅱ, 保温36 h后, pBR322 DNA几乎被切割完全.     

含季铵盐的芳酰腙配体的铜(Ⅱ)配合物的合成和表征：体外DNA键合和核酸酶活性（英文）

制备了2个新的含有N,N,N-三甲基丙烷-1-铵基团和N,N,N-三甲基戊烷-1-铵基团的苯乙酮-(4-羟基苯腙)配体:(E)-3-(4-(1-(2-(4-hydroxybenzoyl)hydrazono)ethyl)phenoxy)-N,N,N-trimethylpropan-1-ammonium perchlorate (H2L1)和(E)-3-(4-(1-(2-(4-hydroxybenzoyl)hydrazono)ethyl)phenoxy)-N,N,N-trimethylpentane-1-ammonium perchlorate (H_2L~2)。以这2个配体分别合成了2个新的铜配合物:[Cu(HL~1)_2]和[Cu(HL~2)_2],研究了这些配体和配合物的DNA结合和切割活性,还研究了DNA切割的机理以及化合物浓度对DNA切割反应的影响。紫外-可见光谱结果表明,所有化合物均优先通过主沟结合模式与DNA结合,在甲基绿(主要的沟结合剂)的存在下切割DNA的活性受到抑制的结果也支持这一结论。电泳研究的结果则表明,化合物在存在或不存在氧化剂(H_2O_2)的情况下均对质粒DNA表现出显著的切割活性,活性主要取决于化合物的浓度。化合物通过水解途径裂解pBR322DNA,在存在不同自由基清除剂情况下的DNA裂解实验也支持这一结论。     

唾液酸酶检测剂(X-Neu5Ac)的合成

以唾液酸为起始原料,在浓硫酸催化下进行甲酯化反应得到唾液酸甲酯,收率比文献方法提高了20%以上;再通过酰氯反应制得化合物4,收率由86.4%提高到98.9%;化合物4于四氢呋喃(THF)中在氢化钠作用下与化合物6进行缩合反应,最后在MeONa醇解与碱作用下水解得到目标产物唾液酸酶检测剂X-Neu5Ac.该合成过程采用浓硫酸催化的方法得到化合物2,原料易得,操作更安全简单,避免了使用昂贵的树脂或者危险性很高的重氮甲烷.在酰氯反应中采用一锅法同时实现了乙酰基保护和氯代反应.另外,对关键中间体7的合成反应条件进行了单因素实验优化,获得了最佳合成条件:反应温度为室温(25℃),加入溶剂量为每g底物20 m L溶剂,反应时间为10 h.通过X-Neu5Ac活性成分的应用研究,发现检测所得产物的稳定性和显色灵敏性均达到要求.采用~1H NMR,ESI-MS和HPLC-MS对产物进行了结构表征.     

Merrifield树脂负载的固相法合成1-氨基-2,4-咪唑二酮

设计了两条新的固相有机合成路线合成了1-氨基-2,4-咪唑二酮化合物4. 一条是由Merrifield树脂负载的羟基苯甲醛1a～1c和氨基脲反应得到缩氨基脲树脂2a～2c, 再在乙醇钠存在下和氯乙酸乙酯成环, 经盐酸切割得到1-氨基-2,4-咪唑二酮; 另一条是将Merrifield树脂用二甲基亚砜氧化氯甲基末端醛化后, 与氨基脲反应得到负载的缩氨基脲6, 经环化、切割得到目标产物4. 这两种方法中用1 mol/L的盐酸代替三氟乙酸作为切割剂, 产物单一、操作简便、可定量反应, 是合成1-氨基-2,4-咪唑二酮化合物的新方法.     

姜黄素桥连卟啉光敏剂的合成及表征

为了开发新的高效光动力治疗光敏剂, 以2-(2-羟基萘基)-5,10,15,20-四苯基卟啉及其Cu(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)配合物为原料, 利用1,6-二溴己烷桥连具有抗癌活性的小分子姜黄素, 设计合成4个新型的天然产物桥连卟啉化合物. 通过UV, ¹H NMR, IR, MS及元素分析等手段对该新型光敏药剂进行了结构表征; 在此基础上, 采用凝胶电泳法考察了化合物在光照和无光照条件下对pBR322质粒DNA的切割能力. 作为潜在光敏剂与DNA相互作用的初步研究表明, 其与DNA结合能力较强, 具有明显的光敏切割效果.     

[Cr(III)(4-ASA)(en)2]Cl配合物的光化学活性

通过吸收光谱、荧光光谱、电导率和ESI-MS质谱等方法讨论了铬配合物[Cr(III)(4-ASA)(en)2]Cl (4-ASA: 4-aminosalicylic acid dianion, en: ethylenediamine)在不同温度、不同pH溶液中的稳定性及光化学稳定性. 实验表明, 该配合物的溶液(pH 7.4)在日光照射下发生了光化学取代反应, 取代产物为[Cr(4-ASA)(en)(H2O)2]＋. 同时研究了配合物及其光照产物对EDTA的动力学反应和对DNA的切割反应. 琼脂糖凝胶电泳实验表明, 配合物的光化学产物[Cr(4-ASA)(en)(H2O)2]＋能有效切割pBR 322 DNA.     

Investigation of DNA cleavage activities of new oxime-type ligand complexes and molecular modeling of complex-DNA interactions

Nucleolytic activities of some new oxime-type ligand complexes were investigated by neutral agarose gel electrophoresis. Analysis of the cleavage products in agarose gel indicated that all complexes used converted supercoiled pUC18 plasmid DNA to its nicked or linear form. It was found that nucleolytic activities of the complexes depend on the complex concentration, reaction time and the presence of a cooxidant (magnesium monoperoxyphthalate, MMPP) in the reaction mixture. However, the complexes cleaved pUC18 plasmid DNA at all investigated pH values. Nucleolytic activities of complexes were investigated for different complex concentrations (0.1–100 μmol L⁻¹), pH values (6.0–10.0) and reaction times (0–60 min). Molecular modeling studies performed by the Hyperchem Software together with DNA-binding studies showed that planar sites of the complexes intercalated into double stranded DNA. It can be concluded that all oxime-type ligand complexes used can be evaluated as nuclease mimics.     

Catalytic hydrolysis of phosphate diester （BNPP） and plasmid DNA by mononuclear macrocyclic polyamine metal complexes

The activities of the catalytic hydrolysis of phosphate diester(BNPP)[bis(p-nitrophenyl)phosphate diester]and plasmid DNA (pUC18)by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper.The results showed that the highest activity in hydrolysis of BNPP was obtained with 1e-Zn(Ⅱ)complex(composed of lipophilic group)as catalyst.The hydrolysis rate enhancement is up to 3.64×10~4 fold.These metal complexes could effectively promote the cleavage of plasmid DNA(pUC18)at physiol...     

Arm effects of mononuclear armed cyclen copper complexes on DNA cleavage

Novel cyclen copper(II) complexes appending different side arms were synthesized as DNA cleavage agents. Both the intermediates and mononuclear complexes were characterized by ¹H NMR, ESI-HRMS, Elemental analyses and IR, and their catalytic activities for DNA cleavage and DNA binding abilities were investigated. The results indicate that the copper(II) complexes could catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) under physiological conditions to produce nicked DNA with high yields (nearly 100%) via an oxidative mechanism in the absence of exogenous agents; The copper complex bearing an 9-anthryl group gave superior DNA interactions to those bearing phenyl or methyl groups.     

Tuning the activity of Zn(II) complexes in DNA cleavage: clues for design of new efficient metallo-hydrolases

The hydrolytic ability toward plasmid DNA of a mononuclear and a binuclear Zn(II) complex with two macrocyclic ligands, containing respectively a phenanthroline (L1) and a dipyridine moiety (L2), was analyzed at different pH values and compared with their activity in bis( p-nitrophenyl)phosphate (BNPP) cleavage. Only the most nucleophilic species [ZnL1(OH)]+ and [Zn2L2(OH)2]2+, present in solution at alkaline pH values, are active in BNPP cleavage, and the dinuclear L2 complex is remarkably more active than the mononuclear L1 one. Circular dichroism and unwinding experiments show that both complexes interact with DNA in a nonintercalative mode. Experiments with supercoiled plasmid DNA show that both complexes can cleave DNA at neutral pH, where the L1 and L2 complexes display a similar reactivity. Conversely, the pH-dependence of their cleavage ability is remarkably different. The reactivity of the mononuclear complex, in fact, decreases with pH while that of the dinuclear one is enhanced at alkaline pH values. The efficiency of the two complexes in DNA cleavage at different pH values was elucidated by means of a quantum mechanics/molecular mechanics (QM/MM) study on the adducts between DNA and the different complexed species present in solution.     

Polydentate cyclotriphosphazene ligands:Design,synthesis and bioactivity

Five multinuclear cyclotriphosphazene ligands were synthesized and tested for their cleavage activities to plasmid DNA.All of these new compounds were confirmed by MS,~1H NMR,~(31)p NMR,~(13)C NMR and IR.Preliminary studies on the cleavage of pUC 19 DNA in the presence of metal complexes were performed.The results revealed that these complexes could act as powerful catalysts under physiological conditions.The complexes 3b+Cu can effectively cleave DNA to nicked form,giving hydrolysis rate constant of 0.0...     

Double-strand hydrolysis of plasmid DNA by dicerium complexes at 37 degrees C.

Significant effort has been made to develop synthetic metal complexes that hydrolyze DNA. Here we report a new dicerium complex, Ce(2)(HXTA) (HXTA = 5-methyl-2-hydroxy-1,3-xylene-alpha,alpha-diamine-N,N,N',N'-tetraacetic acid), which can hydrolyze DNA at pH 8 and 37 degrees C. This complex hydrolyzes DNA restriction fragments to give products with high regioselectivity, affording >90% 5'-OPO(3) and 3'-OH ends, like the products of DNA hydrolyzing enzymes. Ce(2)(HXTA) also hydrolyzes Litmus 29 plasmid DNA to afford both nicked and linear DNA. Analysis of the relative amounts of supercoiled, nicked, and linear DNA present show that there is one double-strand cleavage per ten single-strand cleavages, indicating that the linear DNA formed cannot be the result of two random single-strand cleavage events. The kinetics of nicked and linear DNA formation are comparable, both being associated with apparent first-order rate constants of approximately 1 x 10(-)(4) s(-)(1) for complex concentrations of 10(-)(5)-10(-)(4) M. These observations suggest that similar factors affect the hydrolysis of the first and second DNA strands and that cleaving the phosphodiester bond is likely the rate determining step in both cases. This is the first detailed study of a metal complex shown to mimic DNA hydrolases in their capability to effect double-strand DNA hydrolysis regioselectively at the 3'-O-P bond.     

Hydrolytic cleavage of DNA by quercetin manganese(II) complexes

Quercetin manganese(II) complexes were investigated focusing on its DNA hydrolytic activity. The complexes successfully promote the cleavage of plasmid DNA, producing single and double DNA strand breaks. The amount of conversion of supercoiled form (SC) of plasmid DNA to the nicked circular form (NC) depends on the concentration of the complex as well as the duration of incubation of the complexes with DNA. The maximum rate of conversion of the supercoiled form to the nicked circular form at pH 7.2 in the presence of 100 μM of the complexes is found to be 1.32 × 10⁻⁴ s⁻¹. The hydrolytic cleavage of DNA by the complexes was supported by the evidence from free radical quenching, thiobarbituric acid-reactive substances (TBARS) assay and T4 ligase ligation.     

Synthesis,characterization and biological activities of homo-binuclear Cu(II) and Zn(II) complexes derived from 2-hydroxy-5-methyl-1,3-benzenedicarboxaldehyde derivatives

Few novel binuclear Schiff base metal complexes [M₂LCl₃], where M = Cu(II) and Zn(II); L= 2,6-bis-({2-[(3-hydroxy-4-nitrobenzylidene)amino]ethylimino}methyl)-4-methylphenol (BHEM), 2,6-bis-({2-[(3,4-dimethoxybenzylidene)amino]ethylimino} methyl)-4-methylphenol (BDEM) and 2,6-bis-({2-[(2,3,5-trichlorobenzylidene)amino]ethylimino}methyl)-4-methylphenol (BTEM), have been synthesized and characterized by analytical and spectral data. The data suggest that BHEM/BDEM/BTEM ligands afford square-pyramidal/distorted square-pyramidal geometry on metalation with Zn(II)/Cu(II). The binding behaviour of these complexes with DNA has been investigated using electronic absorption spectroscopy as well as viscosity and voltammetric measurements; the results show that they interact with DNA through intercalating way. From the DNA cleavage study of these complexes, investigated by gel electrophoresis, we found that they efficiently cleave supercoiled pUC19 DNA in the presence of a reducing agent (3-mercaptopropionic acid) and on irradiation with UV light of 360 nm wavelength. The mechanism reveals that singlet oxygen (¹O₂) plays a significant role in the photo cleavage. The superoxide dismutase (SOD) mimetic activity of the synthesized complexes demonstrates that most of the complexes have promising SOD-mimetic activity. The antimicrobial study indicates that the complexes inhibit the growth of bacteria and fungi more than the free ligands.     

手性钌(Ⅱ)配合物对DNA的立体选择性断裂

八面体钌(Ⅱ)多吡啶配合物与双螺旋DNA插入结合后具有较强的结合能力,并且含有一个具有氧化一还原活性的中心金属离子．它们对氧化剂相对比较稳定,但对光比较敏感,因此可利用光辐射使之产生单线态氧或羟基自由基等而使DNA裂解．此外,这些配合物具有左手∧-和右手△-两种构型,与同样具有手性的DNA作用时,存在着立体选择性结合．并且在对DNA的断裂反应中也存在一定的立体选择性,可作为不同构型DNA的结构探针．     

两亲性大环多胺La(III)配合物的合成、表征及催化质粒DNA水解的研究

近年来,人工核酸切割试剂的研究一直是化学生物学、生物化学和分子生物学中最为活跃的前沿领域之一。最近的研究结果表明大环多胺金属配合物在磷酸二酯水解方面表现出独特的催化性能,能作为化学核酸酶有效的催化DNA和RNA的磷酸二酯键的水解[1-2]。尤其是电荷较高的金属阳离子形