脱氧雪腐镰刀菌烯醇与人免疫球蛋白的相互作用研究

利用分子模拟技术结合荧光猝灭法、紫外光谱(UV)、傅立叶红外光谱(FTIR)和圆二色性光谱(CD)在模拟生理条件下研究了脱氧雪腐镰刀菌烯醇(DON)和人免疫球蛋白(H IgG)的结合常数、主要作用力以及DON对HIgG二级结构的影响。在304、310、318 K温度下,测得DON和H IgG的结合常数分别为2.069×104、0.754 9×104、0.523 8×104L.mol-1;其焓变(ΔH)和熵变(ΔS)分别为-78.52 kJ.mol-1、-176.9 J.(mol.K)-1,研究表明其主要作用力为氢键和范德华力。根据F rster能量非辐射转移理论测得结合位置与色氨酸残基间的距离r为4.62 nm。同步荧光、CD和FTIR研究表明,DON使HIgG的二级结构发生了变化。分子模拟显示DON与HIgG的相互作用力主要是氢键和疏水作用,与实验测得的热力学参数提供的作用力信息一致。该研究为DON在人体内的储存、运输、作用机理及毒理学研究提供了理论依据。     

光谱法研究盐酸克伦特罗与人免疫球蛋白之间的相互作用

在模拟生理条件下,采用荧光猝灭光谱、三维荧光光谱、紫外可见吸收光谱及圆二色谱法首次研究了盐酸克伦特罗(Clenbuterol hydrochloride,CL)与人免疫球蛋白G(Human immunoglobulin G,HIgG)之间的相互作用。根据Scatchard方程和Vant Hoff方程计算了不同温度下CL和HIgG的结合常数和热力学常数。荧光猝灭实验结果表明CL可以使HIgG发生荧光猝灭。在298、304、310 K温度下,CL与HIgG间的结合常数分别为2.95×104、2.35×104、1.82×104L/mol,结合位点数分别为0.84、0.87和0.94,表明两者之间的猝灭机理为静态猝灭。在CL与HIgG相互作用的体系中,其焓变和熵变的值分别为-30.47 kJ/mol和-16.58 J·K·mol-1,表明其结合过程可能同时存在几种作用力,主要为氢键和范德华力。通过三维荧光光谱和紫外光谱数据可知:CL的加入会引起HIgG二级结构的变化。此外,当HIgG与CL间的摩尔比为1∶4时,CL的加入可引起HIgGβ-折叠结构含量的减小。     

丁咯地尔与人血清白蛋白结合的光谱学研究

用紫外吸收光谱法、荧光光谱法和傅立叶变换红外光谱法探讨了在模拟人体生理条件下,丁咯地尔与人血清白蛋白(HSA)的结合模式.结果表明:丁咯地尔对HSA的内源荧光有显著的猝灭作用,且猝灭机理主要为静态猝灭.丁咯地尔与HSA形成了1 ∶ 1的复合物,结合常数K=7.43×102 L·mol-1(308 K).根据Fster偶极-偶极非辐射能量转移机理,求得丁咯地尔与HSA间的结合距离r=2.64 nm.由热力学参数确定其作用力以氢键和范德华力为主.同步荧光和傅立叶变换红外光谱表明丁咯地尔对HSA二级结构的含量产生影响,使HSA的α-螺旋结构的含量明显降低,β-折叠和β-转角结构的含量增加.     

分子模拟与光谱法研究愈创木酚和人免疫球蛋白的键合

利用计算机模拟技术结合荧光增敏光谱法、圆二色谱法及傅立叶红外光谱法研究了愈创木-酚与人免疫球蛋白的相互作用. 分子模拟结果显示了愈创木酚与HIgG(Human Immunoglobulin)的键合机理和键合模式, 表明维持药物与蛋白质的相互作用力主要是疏水作用和氢键(位于氨基酸残基LEU 80 和 ASP 65位). 这与实验所得到的热力学参数判定作用力的结果相一致(依据范德霍夫公式计算得DH 0与DS 0的值分别为65.55 kJ · mol^-1和132.95 J · mol^-1 · K^-1). 根据荧光增敏和偏振的有关方程分别求得不同温度下药物与蛋白相互作用的结合常数及结合位点数; 从紫外光谱和同步荧光光谱获得的信息定性地讨论了药物与蛋白相互作用时药物对蛋白构型的影响, 圆二色谱法和红外光谱法(红外去卷积谱和曲线拟合)的结果得到了定量的蛋白质二级结构变化数据. 且利用Förster 能量转移理论, 求得药物与蛋白间的键合距离为4.57 nm. 此外, 基于愈创木酚的荧光敏化效应, 探讨了药物-蛋白质体系的几种物理化参数, 包括电荷密度、离解常数(pK_a)及量子产率的变化效应.     

光谱法与分子模拟技术研究杨梅素与牛血清白蛋白的相互作用

利用紫外光谱、荧光光谱、红边激发荧光位移(REES)法、圆二色谱(CD)结合分子模拟技术共同研究了模拟生理条件下杨梅素与牛血清白蛋白(BSA)的相互作用,阐述了相互作用机制.分子模拟结果表明,杨梅素与蛋白在亚结构域II A的疏水腔内结合,主要作用力为疏水作用力和氢键.依据荧光猝灭法判断猝灭机制为静态猝灭,并得到不同温度下药物与蛋白相互作用的结合常数(Ka)及结合位点数(n),根据热力学参数判断出作用力类型,并且计算出杨梅素与蛋白的结合距离,与分子模拟得到的判定结果基本一致.通过紫外光谱、同步荧光光谱以及REES法获得的信息讨论了相互作用时BSA中色氨酸(Trp)微环境的变化;并利用CD谱的测定结果定量计算了BSA二级结构中α-螺旋含量的变化.     

基于计算模拟与光谱法研究细胞色素CYP2C9与双酚A的相互作用

基于分子对接、分子动力学模拟、紫外吸收光谱法、荧光光谱法与红外光谱法,研究了细胞色素CYP2C9与双酚A (BPA)之间的相互作用。分子对接研究表明,对接位点位于Thr364附近的空腔,结合能为-7. 51 kcal/mol;分子动力学模拟观察了10 ns内蛋白的整体构象变化,发现Thr364也是BPA与CYP2C9发生相互作用时的结合位点。光谱学研究发现CYP2C9与双酚A结合发生荧光增强现象,并且它们间的相互作用力主要为疏水作用力;二级结构中β-转角、无规则卷曲与β-折叠等也发生明显变化;随着底物浓度增加紫外吸收峰有明显上升且伴随红移。模拟计算与光谱检测均表明CYP2C9与BPA间存在较强的相互作用。     

A Comparison Study on the Interaction of Sunset Yellow and β-Carotene with Bovine Serum Albumin

在模拟生理pH条件（pH=7．4）下,采用多种光谱法研究日落黄和β-胡萝卜素与BSA的相互作用,并比较两者与BSA相互作用过程的差异性．通过荧光光谱法和紫外吸收光谱法确定了日落黄和β-胡萝卜素对牛血清白蛋白的荧光猝灭机制,采用Stern—Volmer、双对数方程和热力学公式求出相互作用的猝灭常数、结合常数配、结合位点数月和作用力类型．结果表明：日落黄和β-胡萝卜素对BSA的猝灭属于静态猝灭,两者与BSA的民都达到10^5L／mol,结合位点数均为1,日落黄与BSA的作用力以静电引力为主,而β-胡萝卜素则是通过氢键和范德华力与BSA作用．通过红外光谱法和圆二色谱法研究了二者对BSA构象的影响,结果表明,日落黄与BSA作用的过程中,会引起BSA二级结构的改变,而β-胡萝卜素则对BSA的构象基本不产生影响．     

用分子光谱法研究两种水溶性卟啉与磺丁醚-β-环糊精的超分子体系

本文以紫外可见光谱法和荧光光谱法研究了水溶性的四-(4-甲基吡啶基)卟啉(TMPyP)和四-(4-羧基苯基)卟啉(TCPP)与磺丁醚-β-环糊精(SBE--βCD)形成的超分子体系。结果表明,两种卟啉与磺丁醚-β-环糊精都形成了1∶1的包结物,它们的包结常数分别为1.34×104L.mol-1和1.15×105L.mol-1。     

镉(Ⅱ)与牛血清蛋白相互作用的分子光谱研究

在模拟生理条件下,采用分子荧光、紫外光谱法研究了水溶液中Cd2+与牛血清蛋白(BSA)的相互作用.研究表明,在pH=7.0缓冲液中,以280nm作为激发波长,342nm作为发射波长,Cd2+对BSA的荧光发射有较强猝灭作用.实验测定了Cd2+与BSA在289K,306K和319K温度下的结合常数Ka分别为5.31×104,5.22×104,4.70×104,其热力学参数ΔHm=-3.07kJ·mol-1;ΔSm=79.83J·mol-1·K-1.结果表明导致BSA荧光猝灭是由于分子内的非辐射能量转移而引起的静态猝灭,他们之间的主要作用力是静电作用力.     

新型氨基甲酸乙酯人工抗原的分析表征方法研究

采用1-(3-二甲氨基丙基)-3-乙基碳二亚胺方法合成氨基甲酸乙酯(Ethyl carbamate,EC)新型人工抗原.将衰减全反射红外光谱法(ATR-FTIR)应用于人工合成抗原的表征分析,并结合荧光光谱分析EC人工抗原的偶联效果以及载体蛋白质分子的二级结构变化;通过质谱结合紫外光谱、电泳方法进行人工抗原的系统表征,计算新型人工抗原中半抗原分子与载体蛋白质分子的偶联比.结果表明:合成路线合理,成功获得了氨基甲酸乙酯新型人工抗原.人工抗原分子的α-螺旋、β-折叠和β-转角结构与载体蛋白质分子相比含量发生变化,人工抗原的荧光相图满足线性型态变迁关系,符合“二态模型”.氨基甲酸乙酯人工抗原分析表征的红外衰减全反射方法、基质辅助激光解析飞行时间质谱法获得的检测结果与其它光谱方法、电泳方法表征结果一致,获得人工抗原的偶联比为15∶1～19∶1,EC新型人工抗原免疫小鼠抗血清的效价为1∶25600.     

Spectroscopic Studies on the Interaction of Asiatic Acid with Bovine Serum Albumin

Fluorescence spectroscopy, Fourier transform infrared (FT‐IR) spectroscopy, circular dichroism (CD) and FT‐Raman spectroscopy were employed to analyze the binding of the asiatic acid (AA) to bovine serum albumin (BSA) under simulative physiological conditions. Fluorescence data revealed that the fluorescence quenching of BSA by AA was the result of the formation of BSA‐AA complex. The fluorescence quenching mechanism of BSA by AA was a static quenching procedure. According to the Van′t Hoff equation, the thermodynamic parameters enthalpy change (ΔH⁰) and entropy change (ΔS⁰) for the reaction were evaluated to be ?12.55 kJ·mol^?1 and 67.08 kJ·mol^?1, respectively, indicating that hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The influence of AA on the conformation of BSA has also been analyzed on the basis of FT‐IR, CD and FT‐Raman spectra.     

Thermodynamics of Carbon Dioxide Adsorption on the Protonic Zeolite H‐ZSM‐5

Adsorption of carbon dioxide on H‐ZSM‐5 zeolite (Si:Al=11.5:1) was studied by means of variable‐temperature FT‐IR spectroscopy, in the temperature range of 310–365 K. The adsorbed CO₂ molecules interact with the zeolite Brønsted‐acid OH groups bringing about a characteristic red‐shift of the O? H stretching band from 3610 cm^?1 to 3480 cm^?1. Simultaneously, the ν₃ mode of adsorbed CO₂ is observed at 2345 cm^?1. From the variation of integrated intensity of the IR absorption bands at both 3610 and 2345 cm^?1, upon changing temperature (and CO₂ equilibrium pressure), the standard adsorption enthalpy of CO₂ on H‐ZSM‐5 is ΔH⁰=?31.2(±1) kJ mol^?1 and the corresponding entropy change is ΔS⁰=?140(±10) J mol^?1 K^?1. These results are discussed in the context of available data for carbon dioxide adsorption on other protonic, and also alkali‐metal exchanged, zeolites.     

Thermodynamics of Hydrogen Adsorption on Metal‐Organic Frameworks

Interaction between adsorbed hydrogen and the coordinatively unsaturated Mg²⁺ and Co²⁺ cationic centres in Mg‐MOF‐74 and Co‐MOF‐74, respectively, was studied by means of variable‐temperature infrared (VTIR) spectroscopy. Perturbation of the H₂ molecule by the cationic adsorbing centre renders the H? H stretching mode IR‐active at 4088 and 4043 cm^?1 for Mg‐MOF‐74 and Co‐MOF‐74, respectively. Simultaneous measurement of integrated IR absorbance and hydrogen equilibrium pressure for spectra taken over the temperature range of 79–95 K allowed standard adsorption enthalpy and entropy to be determined. Mg‐MOF‐74 showed ΔH⁰=?9.4 kJ mol^?1 and ΔS⁰=?120 J mol^?1 K^?1, whereas for Co‐MOF‐74 the corresponding values of ΔH⁰=?11.2 kJ mol^?1 and ΔS⁰=?130 J mol^?1 K^?1 were obtained. The observed positive correlation between standard adsorption enthalpy and entropy is discussed in the broader context of corresponding data for hydrogen adsorption on cation‐exchanged zeolites, with a focus on the resulting implications for hydrogen storage and delivering.     

Conformational Polymorphism in N‐(4′‐methoxyphenyl)‐ 3‐bromothiobenzamide

Three conformational polymorphs of N‐(4′‐methoxyphenyl)‐3‐bromothiobenzamide, yellow α, orange β, and yellow γ, have been identified by single‐crystal X‐ray diffraction. The properties and structure of the polymorphs were examined with FT Raman, FTIR (ATR), and UV/Vis spectroscopy, as well as differential scanning calorimetry. Computational data on rotational barriers in the isolated gas‐phase molecule indicate that the molecular conformation found in the α form is energetically preferred, but only by around 2 kJ mol^?1 over the γ conformation. The planar molecular structure found in the β form is destabilized by 10–14 kJ mol^?1, depending on the calculation method. However, experimental evidence suggests that the β polymorph is the most stable crystalline phase at room temperature. This is attributed to the relative planarity of this structure, which allows more and stronger intermolecular interactions, that is, more energetically effective packing. Calculated electronic‐absorption maxima were in agreement with experimental spectra.     

1，1－二氨基2，2－二硝基乙烯（DADE）的热化学性质、热行为和热分解机理

The constant-volume combustion energy, △cU （DADE, s, 298.15 K）, the thermal behavior, and kinetics and mechanism of the exothermic decomposition reaction of 1,1-diamino-2,2-dinitroethylene （DADE） have been investigated by a precise rotating bomb calorimeter, TG-DTG, DSC, rapid-scan fourier transform infrared （RSFT-IR） spectroscopy and T-jump/FTIR, respectively. The value of △cHm （DADE, s, 298.15 K） was determined as （-8518.09±4.59） j·g^-1. Its standard enthalpy of combustion, △cU （DADE, s, 298.15 K）, and standard enthalpy of formation, △fHm （DADE, s, 298.15 K） were calculated to be （-1254.00±0.68） and （- 103.98±0.73） kJ·mol^-1, respectively The kinetic parameters （the apparent activation energy Ea and pre-exponential factor A） of the first exothermic decomposition reaction in a temperature-programmed mode obtained by Kissinger＇s method and Ozawa＇s method, were Ek=344.35 kJ·mol^-1, AR= 1034.50 S^-1 and Eo=335.32 kJ·mol^-1, respectively. The critical temperatures of thermal explosion of DADE were 206.98 and 207.08 ℃ by different methods. Information was obtained on its thermolysis detected by RSFT-IR and T-jump/FTIR.     

Thermal Behavior of N,N＇Bis[N-（2,2,2-trinitroethyl）-N-nitro]ethylenediamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N‐N‐bis[N‐(2,2,2‐tri‐nitroethyl)‐N‐nitro]ethylenediamine in a temperature‐programmed mode have been investigated by means of differential scanning calorimetry (DSC). The results show that kinetic model function in differential form, apparent activation energy E_a and pre‐exponential factor A of this reaction are 3(1 ‐α)^2/3, 203.67 kJ·mol^?1 and 10^20.61s^?1, respectively. The critical temperature of thermal explosion of the compound is 182.2 °C. The values of ΔS^≠ ΔH^≠ and ΔG^≠ of this reaction are 143.3 J·mol^?1·K^?1, 199.5 kJ·mol^?1 and 135.5 kJ·mol^?1, respectively.     

Thermo‐stable 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydro cyclohepta[b]pyridyliron(II) precatalysts toward ethylene polymerization and highly linear polyethylenes

A series of 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydrocyclohepta[b] pyridyliron(II) chlorides was synthesized and characterized using FT‐IR and elemental analysis, and the molecular structures of complexes Fe3 and Fe4 have been confirmed by the single‐crystal X‐ray diffraction as a pseudo‐square‐pyramidal or distorted trigonal‐bipyramidal geometry around the iron core. On activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all iron precatalysts exhibited high activities toward ethylene polymerization with a marvelous thermo‐stability and long lifetime. The Fe4 /MAO system showed highest activity of 1.56 × 10⁷ gPE·mol^?1(Fe)·h^?1 at 70 °C, which is one of the highest activities toward ethylene polymerization by iron precatalysts. Even up to 80 °C, Fe3 /MAO system still persist high activity as 6.87 × 10⁶ g(PE)·mol^?1(Fe)·h^?1, demonstrating remarkable thermal stability for industrial polymerizations (80–100 °C). This was mainly attributing to the phenyl modification of the framework of the iron precatalysts. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 830–842     

Spectroscopic Studies on the Binding of Kaempferol‐3,7‐α‐L‐rhamnopyranoside to Bovine Serum Albumin

The binding of kaempferol‐3,7‐α‐L‐rhamnopyranoside (KRR) with bovine serum albumin (BSA) was investigated by different spectroscopic methods under simulative physiological conditions. Analysis of ?uorescence quenching data of BSA by KRR at different temperatures using Stern‐Volmer methods revealed the formation of a ground state KRR‐BSA complex with moderate binding constant of the order 10⁴ L·mol^?1. The existence of some metal ions could weaken the binding of KRR on BSA. The changes in the van't Hoff enthalpy (ΔH⁰) and entropy (ΔS⁰) of the interaction were estimated to be ?26.53 kJ·mol^?1 and 3.33 J·mol^?1·K^?1 and both hydrophobic and electrostatic forces contributed to stabilizing the BSA‐KRR complex. According to the F?ster theory of non‐radiation energy transfer, the distance r between the donor (BSA) and the acceptor (KRR) was obtained (r=2.83 nm). Site marker competitive experiments showed that KRR could bind to Site I of BSA. In addition, synchronous fluorescence, UV‐Vis absorption and circular dichroism (CD) results indicated that the KRR binding could cause conformational changes of BSA.     

4-硝基苯甲醇的低温热容和标准摩尔生成焓

用精密自动绝热量热计测定了4-硝基苯甲醇（4-NBA）在78 ~ 396 K温区的摩尔热容。其熔化温度、摩尔熔化焓及摩尔熔化熵分别为:(336.426 ± 0.088) K, (20.97 ± 0.13) kJ×mol-1 和 (57.24 ± 0.36) J×K-1×mol-1.根据热力学函数关系式,从热容值计算出了该物质在80 ~ 400 K温区的热力学函数值 [HT - H298.15 K] 和[ST - S298.15 K]. 用精密氧弹燃烧量热计测定了该物质在T＝298.15 K的恒容燃烧能和标准摩尔燃烧焓分别为 (C7H7NO3, s)＝- ( 3549.11 ± 1.47 ) kJ×mol-1 和 (C7H7NO3, s)＝- ( 3548.49 ± 1.47 ) kJ×mol-1. 利用标准摩尔燃烧焓和其他辅助热力学数据通过盖斯热化学循环, 计算出了该物质标准摩尔生成焓 (C7H7NO3, s)＝- (206.49 ± 2.52) kJ×mol-1 .     

Interaction Between Ginkgolic Acid and Human Serum Albumin by Spectroscopy and Molecular Modeling Methods

The interaction of ginkgolic acid (15:1, GA) with human serum albumin (HSA) was investigated by FT–IR, CD and fluorescence spectroscopic methods as well as molecular modeling. FT–IR and CD spectroscopic showed that complexation with the drug alters the protein’s conformation by a major reduction of α-helix from 54 % (free HSA) to 46–31 % (drug–complex), inducing a partial protein destabilization. Fluorescence emission spectra demonstrated that the fluorescence quenching of HSA by GA was by a static quenching process with binding constants on the order of 10⁵ L·mol^?1. The thermodynamic parameters (ΔH = ?28.26 kJ·mol^?1, ΔS = 11.55 J·mol^?1·K^?1) indicate that hydrophobic forces play a leading role in the formation of the GA–HSA complex. The ratio of GA and HSA in the complex is 1:1 and the binding distance between them was calculated as 2.2 nm based on the Förster theory, which indicates that the energy transfer from the tryptophan residue in HSA to GA occurs with high probability. On the other hand, molecular docking studies reveal that GA binds to Site II of HSA (sub-domain IIIA), and it also shows that several amino acids participate in drug–protein complexation, which is stabilized by H-bonding.