Study of the interaction of aglycon of daunorubicin with human serum albumin by spectroscopy and modeling

The interaction between aglycon of daunorubicin (DNR-A) and human serum albumin (HSA) was investigated using fluorescence quenching and modeling. Results shown that fluorescence quenching of HSA by DNR-A resulted from the formation of DNR-A-HSA complex. The quenching constants were determined via measurement of the binding affinity between DNR-A and HSA using the Stern-Volmer equation. The thermodynamic parameters DeltaG, DeltaH, DeltaS and the binding distance r were calculated. Furthermore, SFS and UV spectra suggested that the complex changed the conformation of HSA and that hydrophobic interactions played a major role in DNR-A-HSA association, which was in good agreement with the results of the modeling study. Moreover, the SFS technique was successfully applied to determine the total proteins in biology samples with satisfactory results.     

氟罗沙星与人血清白蛋白相互作用研究

以光谱技术和微量热技术相结合的方法研究水溶液中氟罗沙星分子及铁存在时与人血清白蛋白之间结合作用的机制,用荧光淬灭法测得两反应的结合常数分别为K=1.19×l05L·mol-1和1.0565×105L·mol-1,结合位点数0.97和0.835.依据Fōrster非辐射能量转移机制,得到氟罗沙星与人血清白蛋白间的结合距离(r=3.23nm).用同步荧光技术考察氟罗沙星对人血清白蛋白构象的影响.微量热法测得氟罗沙星与人血清白蛋白反应的ΔH≈0,ΔS＞0,氟罗沙星分子在铁离子存在时与人血清白蛋白反应的ΔH＜0,并且ΔS＞0表明它们的作用都主要为静电力.由于焓熵互补的作用,两反应的自由能没有发生大的变化.     

水杨酸与人血清白蛋白的相互作用研究

采用荧光光谱法,紫外光谱法及圆二色谱法研究了具抗凝血作用的水杨酸与人血清白蛋白(HSA)的相互作用.结果表明,水杨酸对人血清白蛋白荧光产生猝灭现象,猝灭方式为静态猝灭.通过同步荧光法和圆二色谱法发现水杨酸的存在明显改变人血清白蛋白的构象.     

洛美沙星与人血清白蛋白的相互作用机理

利用荧光及紫外光谱法研究了水溶液中洛美沙星(LMX)与人血清白蛋白(HSA)的相互作用机理. 结果表明洛美沙星对人血清白蛋白的荧光有较强的猝灭作用, 其猝灭类型主要为静态猝灭. 在不同温度下求得了洛美沙星与人血清白蛋白的结合常数K, 发现随反应温度上升K值下降. 由热力学参数确定了洛美沙星与人血清白蛋白的结合作用主要为色散力. 用同步荧光技术考察了洛美沙星对人血清白蛋白构象的影响, 又根据Fōrster理论, 测得了洛美沙星与人血清白蛋白之间的能量转移效率, 相互结合距离. 进一步证明了该反应是单一静态猝灭过程, 阐述了其猝灭机理是通过能量转移产生的.     

秋水仙碱与人血清白蛋白相互作用的光谱学和电化学研究

用荧光光谱、紫外吸收光谱和电化学方法研究了在近似生理条件下秋水仙碱与人血清白蛋白的相互作用.研究表明,秋水仙碱对人血清白蛋白的荧光猝灭主要是静态猝灭过程,秋水仙碱使人血清白蛋白的构象发生变化.与此同时,在pH=7.4、含0.05%吐温-20的磷酸盐缓冲液中,秋水仙碱在玻碳电极上出现一不可逆的氧化峰,加入人血清白蛋白后秋水仙碱的氧化峰电位正移,峰电流下降.此外,利用光谱学方法和电化学方法测定的秋水仙碱与人血清白蛋白相互作用的结合常数和结合位点数吻合.     

Spectroscopic investigation of interaction between bionanserin and human serum albumin

采用荧光光谱研究了模拟生理务件下抗精神病药布南色林与人血清白蛋白的相互作用,结果表明,布南色林对人血清白蛋白的内源性荧光具有猝灭作用且猝灭方式为静态猝灭.布南色林与人血清白蛋白形成了1∶1的复合物,结合常数K=1.80×104L/mol,且金属离子对结合反应具有较显著的影响.根据不同温度下的热力学函数确定了布南色林与人血清白蛋白的相互作用力类型以氢键和范德华力为主.同步荧光光谱和傅立叶变换红外光谱表明布南色林对人血清白蛋白二级结构的含量产生影响,α-螺旋和β-折叠的含量降低,β-转角和无卷曲规则的含量明显升高.     

布南色林与人血清白蛋白相互作用的光谱学研究

采用荧光光谱研究了模拟生理务件下抗精神病药布南色林与人血清白蛋白的相互作用,结果表明,布南色林对人血清白蛋白的内源性荧光具有猝灭作用且猝灭方式为静态猝灭.布南色林与人血清白蛋白形成了1∶1的复合物,结合常数K=1.80×104L/mol,且金属离子对结合反应具有较显著的影响.根据不同温度下的热力学函数确定了布南色林与人...     

苯溴马隆与牛血清白蛋白相互作用的研究

通过荧光光谱法和紫外吸收光谱法研究了模拟人体生理条件下苯溴马隆与牛血清白蛋白(BSA)的反应结合特征。结果表明,苯溴马隆对牛血清白蛋白的荧光具有静态猝灭作用,且用同步和三维荧光光谱研究了其对BSA构造的影响。通过F ster非辐射能量转移理论和Lineweave-Burk方程式分别得出了两者的作用距离、结合反应的结合常数和结合位点数。此外,还求算了结合过程的基本热力学参数。     

用光谱法研究奥硝唑与人血清白蛋白的相互作用

采用荧光光谱法和紫外可见吸收光谱法研究了奥硝唑与人血清白蛋白之间的相互作用;求得了二者在不同温度下的结合常数KA和结合位点数n,以及对应温度下结合反应的热力学参数,同时采用同步荧光分析技术探讨了蛋白质与药物结合时构象的变化.结果表明,在生理条件下奥硝唑对人血清白蛋白的荧光猝灭主要为静态猝灭;奥硝唑与人血清白蛋白主要靠静电作用力结合.     

Molecular interaction and energy transfer between human serum albumin and polyoxometalates

As a step toward the elucidation of the mechanistic pathways governing the known bioactivity of polyoxometalates (POMs), two representative molecules of this class of chemicals, the wheel-shaped [NaP(5)W(30)O(110)]14- (P(5)W(30)) and the Keggin-type anion [H(2)W(12)O(40)]6- (H(2)W(12)), are shown, by two independent techniques, to interact with the fatty-acid-free human serum albumin (HSA). The excited-state lifetime of the single tryptophan molecule of this protein is dramatically decreased by the binding. The quenching mechanism is found to constitute the first example of energy transfer between HSA and POMs. Such molecular recognition is believed to be a key step for subsequent evolution of the systems. Circular dichroism (CD) was used to assess the structural effects of POM binding on HSA and to confirm the interaction revealed by fluorescence studies. CD experiments showed that the two POMs have different effects on the secondary structure of the protein. Binding P(5)W(30) partially unfolds the protein whereas H(2)W(12) has no remarkable effect on the structure of the protein.     

Study on the interaction between thiazolopyrimidine analogues and bovine serum albumin

Fluorescence and ultraviolet spectroscopy were used to explore the interaction between thiazolopyrimidines (TAPM) and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results show that thiazolopyrimidines can quench the fluorescence of BSA through a static quenching process. The binding constants, binding sites, and thermodynamic parameters at different temperatures were calculated. The calculated results indicate that the interaction between thiazolopyrimidines and BSA is driven mainly by Van der Waals' force and hydrogen bonds. The binding distances r was obtained based on F?rster theory of non-radiation energy transfer. The comparison of binding potency of thiazolopyrimidines and BSA suggests that the substituent on the benzene ring promotes the binding process of thiazolopyrimidines and BSA.     

5种荧光染料探针与牛血清白蛋白相互作用研究

采用荧光光谱法研究了水溶液中四溴荧光素、四氯四溴荧光素、二碘荧光素、乙基罗丹明B、健那绿B等5种荧光染料探针与牛血清白蛋白(BSA)的相互作用.实验表明,这5种染料探针同牛血清白蛋白结合时,疏水作用力起决定性作用,静电力起次要作用,相比之下牛血清白蛋白(BSA)结合阴离子的能力最强,其次为中性分子,最后为阳离子.通过疏水作用力,5种染料均是以非极性苯基进入BSA疏水性腔体中同色氨酸残基发生作用,弱氢键的形成加强了这种作用力,且使得光谱间能量转移效率明显提高.5种染料探针的极性部位由于极性和空间效应的原因难以进入腔体内部,致使反应均按接近1∶1的方式进行.     

甲苯胺蓝与牛血清白蛋白作用的光谱特性研究

应用荧光光谱法研究了甲苯胺蓝(TB)与牛血清白蛋白(BSA)相互作用的光谱特性.测定了TB与BSA在20℃,30℃和40℃3个温度下的结合常数KA分别为8.94×103,1.75×104,1.74×104L/mol,结合位点数n分别为0.66,0.71和0.93.实验表明:TB与BSA的荧光猝灭主要为静态猝灭;利用Gibbs-Helmholtz方程计算得到热力学参数ΔH为49.416kJ,ΔS为244.876J.mol-1.K-1,探讨了它们的相互作用机理,结果表明TB主要以氢键作用力与BSA相互作用;应用同步荧光技术研究了TB对BSA构象的影响.     

6-苄氨基嘌呤与牛血清白蛋白作用荧光特性的研究

应用荧光光谱法研究了6-苄氨基嘌呤（6-BA）与牛血清白蛋白（BSA）相互作用的荧光特性。测得了6-BA与BSA在10、27、40℃温度下的结合常数KA为：0.21×10^5、1.37×10^5、5.53×10^5L/mol,结合位点数n为：1.0、1.2、1.3。6-BA对BSA内源荧光的猝灭机理主要为静态猝灭,6-BA主要以疏水作用与BSA相互作用,BSA的荧光主要源于色氨酸残基,6-BA对BSA的构象有影响。     

牛血清白蛋白与光谱探针相互作用机理的研究

在酸性条件下研究了考马斯亮蓝光谱探针与牛血清白蛋白结合物的光学性质,探讨了考马斯亮蓝染料和蛋白质的相互作用机理。研究结果表明染料考马斯亮蓝的疏水作用和亲水作用的协调作用以及与生物大分子蛋白质具有相反电荷的静电作用,是光谱探针与生物大分子形成大分子聚集体的必要因素。     

阿魏酸哌嗪与牛血清白蛋白相互作用的研究

在模拟人体生理条件下,用常规荧光光谱法和紫外-可见吸收光谱法研究阿魏酸哌嗪和牛血清白蛋白结合反应的特征,并利用同步荧光法和三维荧光法研究了阿魏酸哌嗪与牛血清白蛋白作用前后白蛋白的构象变化.研究表明:阿魏酸哌嗪与牛血清白蛋白形成复合物,从而猝灭牛血清白蛋白的内源性荧光.该过程为静态猝灭过程.根据Stem-Volmer方程求出不同温度下的结合位点数和结合常数;根据Fsmter非辐射能量转移理论可求出其作用距离r=2.33nm:根据基本热力学参数△H、△S和△G判断阿魏酸哌嗪和牛血清白蛋白主要通过氢键和范德华力发生相互作用.     

2,4-二硝基苯胺与牛血清白蛋白相互作用的研究

通过荧光和紫外光谱法研究了2,4-二硝基苯胺同牛血清白蛋白(BSA)的相互作用. 2,4-二硝基苯胺对牛血清白蛋白的内源荧光具有强烈的猝灭作用. 二者之间形成不发荧光的复合物是导致荧光猝灭的主要原因. 计算了其结合常数和结合位点数. 紫外光谱法进一步证明了其猝灭机理为静态猝灭. 根据能量转移理论计算了作用距离(3.13 nm). 同步荧光的结果表明2,4-二硝基苯胺的存在改变了牛血清白蛋白的分子构象.     

铈配合物与人血清白蛋白相互作用的研究

在生理条件(pH=7.4)下,利用荧光光谱和紫外光谱探讨了华法灵铈与人血清白蛋白(HSA)的相互作用。根据荧光和紫外光谱可知,华法灵铈配合物对人血清白蛋白荧光产生猝灭作用,其猝灭方式为静态猝灭。并通过Stern-Volmer方程等,计算出了配合物与人血清白蛋白的静态猝灭常数、结合常数和结合位点数。根据一系列热力学参数ΔH,ΔS,ΔG的相对大小,确定出配合物与人血清白蛋白的主要作用力类型为静电作用力。且用同步荧光法讨论了华法灵铈对HSA构象的影响。     

Investigation on the interaction between a heterocyclic aminal derivative, SBDC, and human serum albumin

The interaction between a novel promising drug (spiro[(2R,3R,4S)-4-benzyloxy-2,3-isopropylidene-dioxy-1-oxa-cyclopentane-5,5′-(2-benzoylmethylene-1,3-diaza-cyclohexane)] (SBDC)) and human serum albumin (HSA) under physiological conditions has been investigated by using fluorescence, absorption, and circular dichroism (CD) spectroscopic techniques in combination with protein–ligand docking study. It was observed that SBDC has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The association constants of SBDC with HSA were determined at different temperatures based on fluorescence quenching results. The negative ΔH and positive ΔS values in case of SBDC–HSA complex showed that apart from an initial hydrophobic association, both van der Waals interactions and hydrogen bonding play a vital role in the binding of SBDC to HSA. The quantitative analysis data of CD spectra showed that the binding of SBDC to HSA induced conformational changes in HSA and the α-helix of 52.1% in free HSA increased to 55.7% in HSA–SBDC complex. The distance between donor (HSA) and acceptor (SBDC) was obtained according to the Förster's theory of non-radiation energy transfer. Data obtained by spectroscopic techniques and protein–ligand docking study suggested that SBDC binds to residues located in subdomain IIA of HSA.