巴洛沙星-Tb^3＋-ATP荧光体系的建立及其分析应用

在二元配合物巴洛沙星-Tb^3＋中加入ATP,Tb^3＋在其特征波长545nm处的荧光强度增强,据此建立了新的巴洛沙星Tb^3＋-ATP荧光体系。在最优化实验条件下,增强的荧光强度与ATP的浓度呈良好的线性关系,线性范围为2．0×10^-6-3．0×10^-5mol／L,检出限为8．0×10^-7mol／L。详细的机理研究表明,ATP能与巴洛沙星-Tb^3＋形成大的三元络合物荧光体系。新建立的荧光体系成功地应用于ATP注射液中ATP的定量检测。对不同批次ATP注射液进行加标回收试验,回收率为101％-106％,测定结果的相对标准偏差为1．1％-1．9％（n=5）。     

1,3-丙二胺邻苯二酚钼钨手性八面体配合物的仿生合成、晶体结构以及与ATP作用的液相NMR研究

合成了1,3-丙二胺邻苯二酚钼钨手性八面体配合物(NH₃CH₂CH₂CH₂NH₂)₂[Mo_0.4W_0.6O₂(C₆H₄O₂)₂],并对其进行了单晶结构解析,研究了其与ATP作用的液相NMR谱.该晶体属正交晶系,空间群为Pcan.晶胞参数a=0.7501(2)nm,b=2.3994(7)nm,c=1.2178(4)nm,Z=4.[Mo_0.4W_0.6O₂(C₆H₄O₂)₂]^2-的配位几何构型为手性八面体,晶体为外消旋体.配位阴离子中MoW中心金属离子除了与两个端基O配位形成cis-MO键外,同时还分别与两个邻苯二酚配位基团的的氧原子配位,形成4个M-Ob(M=Mo,W)键,构成两个五元环.利用¹HNMR,¹³CNMR,³¹PNMR以及¹H-¹⁵NHMBC对标题配合物及其与ATP在D₂O溶剂中的作用进行了研究,发现标题配合物的MoW中心金属离子在纯D₂O溶剂中被还原成+5价,但与ATP混合后转化为+6价,且与原配位基邻苯二酚发生解离.解离后的[MO₂]²⁺最大可能与腺嘌呤上的氨基N原子配位,而此配位可能是其抗癌抗肿瘤活性的主要作用机理之一.     

三元混配M（ATP）（3,4—Lu）^2—配合物的稳定性研究

25℃下,用pH电位滴定法研究了二元M(3,4Lu)2 和三元混配M(ATP)(3,4Lu)2-配合物(ATP4-=三磷酸腺苷,3,4Lu=3,4二甲基吡啶,M2 =Co2 ,Ni2 ,Cu2 或Zn2 )在水溶液中的稳定性,三元混配配合物相对于二元配合物的稳定性用M(3,4Lu)2 M(ATP)2-=M(ATP)(3,4Lu)2- M2 的平衡常数ΔlogKM(=logKM(ATP)M(ATP)(3,4Lu)-logKMM(3,4Lu))表示,结果比统计值大,这可能主要归因于三元混配配合物分子内ATP4-与3,4Lu之间的σ-π协同效应及其芳环间的堆积作用,′HNMR谱研究确证了这种堆积作用的存在。     

High-temperature fluorescence of low- and high concentration aqueous ATP solution

Abstract

The results of an experimental study of luminescence of an aqueous solution of adenosine triphosphate (ATP) at room temperature are presented. High-temperature fluorescence of low- and high-concentrated solution was experimentally detected and analyzed. The shape of the fluorescence spectrum, the excited state lifetime and the temperature behavior of the emission intensity indicate the formation in the high-concentrated solution of rather stable dimer-like complexes, which can form excimer states.     

Energy,Life, and ATP (Nobel Lecture)

The puzzling results of ¹⁸ O-exchange experiments churned in Paul Boyer's mind, and he realized that the proton-motive force generated upon oxidative phosphorylation is not used primarily for the synthesis of an ATP molecule, but instead its release. The concept of the binding change mechanism was born. For the formation of ATP from ADP and inorganic phosphate—one of the most important reactions in nature—catalysis by ATP synthase requires sequential conformational changes and a rotary mechanism that drives these changes; this enzyme is truly a remarkable molecular machine.     

Antibacterial Mode of Action of the Daucus carota Essential Oil Active Compounds against Campylobacter jejuni and Efflux-Mediated Drug Resistance in Gram-Negative Bacteria

Today, an alarming rise of bacterial gastroenteritis in humans resulting from consuming Campylobacter-tainted foods is being observed. One of the solutions for mitigating this issue may be the antibacterial activity of essential oils. In the present research, we propose to study the antibacterial activity against Campylobacter and other Gram-negative bacteria of Daucus carota essential oil and its active molecules. In addition, a few chemically synthesized molecules such as (E)-methylisoeugenol, Elemicin, and eugenol were also studied. The results showed that the essential oil itself and its most active component, (E)-methylisoeugenol, exhibited bactericidal effects. Similar effects were detected using purified and chemically synthesized molecules. Also, it was observed that the Daucus carota essential oil and its active molecules affected intracellular potassium and intracellular ATP contents in Campylobacter cells. Inhibition of the membrane bound F_OF₁-ATPase was also observed. Eventually, for the first time, the efflux mechanism of active molecules of Daucus carota essential oil was also identified in gamma proteobacteria and its specific antibacterial activity against Campylobacter jejuni was associated with the lack of this efflux mechanism in this species.     

Steered molecular dynamics simulations for uncovering the molecular mechanisms of drug dissociation and for drug screening: A test on the focal adhesion kinase

Drug‐binding kinetics could play important roles in determining the efficacy of drugs and has caught the attention of more drug designers. Using the dissociation of 1H‐pyrrolo[2,3‐b]‐pyridines from the focal adhesion kinase as an example, this work finds that steered molecular dynamics simulations could help screen compounds with long‐residence times. It also reveals a two‐step mechanism of ligand dissociation resembling the release of ADP from protein kinase A reported earlier. A phenyl group attaching to the pyrrole prolongs residence time by creating a large activation barrier for transition from the bound to the intermediate state when it becomes exposed to the solvent. Principal component analysis shows that ligand dissociation does not couple with large‐scale collective motions of the protein involving many of its amino acids. Rather, a small subset of amino acids dominates. Some of these amino acids do not contact the ligands directly along the dissociation pathways and could exert long‐range allosteric effects. © 2018 Wiley Periodicals, Inc.     

Intramolecular stacking interaction in mixed-ligand complexes containing ATP4- and aromatic N-heterocyclic ligands

The stability constants of the binary ML2+ and ternary M(ATP)L2- complexes,where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn2+ or Cd2+,have been determined by poten-tiometric pH titration in aqueous solution at I=0.1 mol/L (NaClO4),T=25℃.The stability of the ternary complexes characterized by corresponding to the equilibrium M(ATP)2-+ML2+=M(ATP)L2-+M2+ is higher than what would be expected on statistical grounds.The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP4- 1H NMR studies of Zn2+/ATP4-/L confirm the presence of stacking in the ternary complexes.It is concluded that the strength of the intramolecular stacking interaction is dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge.Possible implications are discussed briefly.     

荧光素酶法测定活性污泥中的ATP

选择了４种不同的提取剂，对曝气池活性污泥的腺苷三磷酸进行提取，并用荧光素酶法进行了测定。结果表明，不同提取剂所提取的ＡＴＰ量有很大不同；同一提取剂对不同水样ＡＴＰ的提取效果也不同。     

铁(Ⅲ)离子在ATP与去铁转铁蛋白之间交换动力学的研究

使用分光光度法研究了Fe(Ⅲ)离子在去铁转铁蛋白(apoTf)与ATP之间的交换动力学,得到反应的动力学参数及反应速率表达式,并提出了反应机理。