纳米颗粒与蛋白质分子的相互作用

纳米技术的快速发展和广泛应用前景,引起了人们对纳米生物效应和安全性问题的普遍关注。为保证纳米技术的健康持续发展,纳米颗粒与生物体的相互作用以及产生的生物学效应不容忽视。为充分了解纳米颗粒物产生的生物学效应,阐明纳米颗粒如何进入生物体以及与生物体相互作用的分子过程至关重要。在总结国内外相关研究的基础上,本文介绍了纳米颗粒进入机体的主要途径,并系统综述了纳米颗粒与蛋白质分子的相互作用及其表征方法,以及纳米颗粒与蛋白质相互作用对蛋白质结构功能和纳米颗粒生物效应的影响。     

含缩醛正离子类脂分子与蛋白质的相互作用

Interactions of a series of dialkyl cationic lipids linking with bovine serum albumin (BSA) through acetal (linker) have been studied by the fluorescence spectroscopy. At low concentrations of cationic lipids, the fluorescence intensity of BSA decreased with binding of cationic lipid, and the maximum of emission wavelength shifted from (344±1)nm to (331±1)nm. It indicates that the BSA goes to uncoiled flexible conformation from its native structure. When the concentrations of lipids increased, the fluorescence intensity increased rapidly and then maintained unchanged. It reveals that two tryptophan residues of BSA are all enwrapped in the bilayer membrane, owing to the hydrophobic interactions between lipids and BSA.     

高岭石与水分子相互作用的理论研究

为从微观角度深入探讨单个水分子与高岭石最易解理晶面不同暴露末端的作用特点,本工作通过密度泛函理论的计算方法对不同吸附形态的水分子与不同暴露末端的稳定作用构型进行几何结构与电子结构分析.吸附能的计算结果表明水分子在铝氧八面体羟基作为暴露末端的表面上最稳定的吸附方式为水分子的氧原子和氢原子分别与相邻两个羟基的氢原子和氧原子...     

分子间相互作用对蛋白质晶体生长的影响

采用原子力显微镜对溶菌酶和刀豆蛋白A的分子间相互作用力的情况进行了研究, 并用动态光散射研究了此二种分子间相互作用力有较大差异的蛋白质在晶体生长条件和非生长条件下, 溶液中的聚集体的状态(大小和分散度)随浓度和温度的变化情况. 实验结果表明, 范德华力强的刀豆蛋白A在成核前, 溶液中的聚集体不能很快转变为生长基元, 导致晶体生长时间长; 而范德华力弱的溶菌酶, 溶液中的聚集体可以很快转变成生长基元, 晶体生长时间也较短.     

纳米材料-蛋白质界面相互作用的分子机制

纳米材料由于其优异的性能在化工、电子、机械、环境、能源、航天等各个领域已经得到了广泛的应用,并且在生物医学方面的应用越来越受到重视。纳米材料-蛋白质界面相互作用是纳米生物医学领域重要的科学问题,对于纳米材料的生物医学应用以及生物安全性评价至关重要。蛋白质分子与纳米材料在界面的相互作用,一方面可以诱导蛋白质的构象、组装结构甚至功能的改变,另一方面可以引起纳米材料的表面亲疏水性、电荷性质等表面物理化学性质的改变。基于蛋白质与纳米材料相互作用检测技术及结果,本文从分子水平阐述了纳米材料与蛋白质分子在界面之间的相互作用机理及相应的结构与性质的变化,从而可以深化对两者之间复杂的相互作用机制的理解,对于推进纳米材料在生物医学的应用及健康、安全、持续发展具有重要意义。     

氯氮平与蛋白质相互作用的研究

用荧光光谱法和紫外-可见光谱法研究了在模拟人体生理条件下,氯氮平和牛血清蛋白（BSA）结合反应的特征,发现氯氮平对BSA有较强的荧光猝灭作用,且氯氮平的紫外吸收光谱和BSA的荧光光谱有一定程度的重叠,由此可得出其作用距离和结合过程的基本热力学参数。     

石墨烯材料与蛋白质的相互作用

石墨烯材料凭借其优异的物理化学性质在生物化学以及生物医学领域备受关注,展现出了广阔的应用前景。值得注意的是,石墨烯材料在应用于载药、医学检测与诊断及生物成像等诸多领域时,会不可避免地与生物体内的各种蛋白质分子产生相互作用,进而改变石墨烯材料自身的理化性质并影响蛋白质的构象及生物学功能。因此研究石墨烯材料与蛋白质分子之间的相互作用,对于理解和评估其生物学效应,开发新型生物化学技术,具有至关重要的意义。本文综述了近年来针对石墨烯材料与蛋白质分子相互作用开展的代表性的科学研究,分类介绍了石墨烯家族中的各种材料与蛋白质相互作用的分子机制与规律,并介绍了基于蛋白质分子与石墨烯材料相互作用开发的新型应用技术,最后对这一领域未来的热点研究方向进行了分析和展望。     

最优特征子集预测蛋白质与蛋白质的相互作用

蛋白质与蛋白质相互作用的识别有助于研究蛋白质功能和发现潜在的药物靶标。本研究采用氨基酸组成、二肽组成、三联子组成、组成、转变、分布和自相关特征对蛋白质与蛋白质相互作用对进行表征。基于最小冗余最大相关方法选择最优特征子集,结合支持向量机对酵母蛋白质与蛋白质相互作用进行了预测研究。通过采用最优特征子集,训练集和测试集的预测精度分别比二肽组成的提高了4%和2%,表明了当前方法的有效性。     

蛋白质-蛋白质相互作用界面统计分析

以作者开发的从蛋白质结合部位推导出其界面所具有的疏水性质和氢键性质的计算程序PP_SITE为基础,利用蛋白质结构数据库(PDB),对蛋白质-蛋白质相互作用界面进行了统计分析.从PDB中挑出非冗余的链间相互作用对,计算出这个数据集中所有链间界面的疏水和氢键相互作用特征.对得到的界面特征进行统计分析,寻找能够明显聚类的界面特征.结果表明，界面大小、氢键和疏水相互作用在界面所占比例以及疏水相互作用的集中程度可以作为分类的依据.     

山奈素与蛋白质相互作用的电化学行为研究

应用循环伏安法研究山奈素在活化玻碳电极上的电化学行为及其与人血清白蛋白(HSA)的相互作用,建立差示脉冲伏安法测定HSA的新方法.在pH4.5的磷酸盐缓冲液(PBS)中,山奈素可与HSA形成超分子复合物,导致前者在0.468V处的氧化电流峰下降,其下降值与HSA浓度在0.05～0.25mg/L范围呈线性关系,检出限为0.008mg/L,可应用于血清样品测定.     

Water Interaction with Iron Oxides

We present a mechanistic study on the interaction of water with a well‐defined model Fe₃O₄(111) surface that was investigated by a combination of direct calorimetric measurements of adsorption energies, infrared vibrational spectroscopy, and calculations bases on density functional theory (DFT). We show that the adsorption energy of water (101 kJ mol⁻¹) is considerably higher than all previously reported values obtained by indirect desorption‐based methods. By employing ¹⁸O‐labeled water molecules and an Fe₃O₄ substrate, we proved that the generally accepted simple model of water dissociation to form two individual OH groups per water molecule is not correct. DFT calculations suggest formation of a dimer, which consists of one water molecule dissociated into two OH groups and another non‐dissociated water molecule creating a thermodynamically very stable dimer‐like complex.     

Interaction of Trypan Blue with Protein and Application

The microphase adsorption ‐ spectral correction (MPASC) technique has been described and applied to the aggregation of trypan blue (TB) in proteins. The formation of the microelectrostatic field in protein causes the Langmuir monolayer aggregation of TB. The adsorption ratio of TB to bovine serum albumin (BSA), ovalbumin (OVA), hemoglobin (Hb) and human γ‐globulin (γ‐G) was determined to be 14.8, 8.4, 2.8 and 27.6, respectively, and the adsorption constant of the aggregates to be 7.17 × 10⁵, 4.88 × 10⁶, 4.85 × 10⁶ and 2.99 × 10⁶. The adsorption ratio of TB to proteins interestingly indicates almost no relation to the array sequence of amino acid residues. The interaction of TB with proteins is sensitive at pH 3.29, and the reaction was applied to the determination of protein trace with satisfactory results.     

Thermodynamic Studies of Myelin Basic Protein upon Interaction with Zinc

The interaction of myelin basic protein (MBP) from bovine central nervous system with divalent zinc ion was studied by UV‐Vis titration spectrophotometry and isothermal titration calorimetry techniques at 27°C in Tris buffer solution at pH = 7.2. MBP has one binding site for a zinc ion. The binding of a zinc ion is endothermic (ΔH = + 159 kJ mol^?1) with a dissociation binding constant of 0.445 μM. The results obtained by two previous methods of isothermal titration spectrophotometry and calorimetry are similar and consistent with the result obtained from a new calculation method of calorimetric data analysis according to the Scatchard plot.     

Gravimetric Study of Interaction of Water Vapour with Metallic Zinc

The interaction between samples of metallic zinc and water vapour was studied gravimetrically, both in the absence and in the presence of oxygen. The experimental total mass gain vs. time curves exhibited two plateaus, whose heights increased with, elevations both of relative humidity and of temperature. The amount of product retained on the surface after desorption was also determined as a function of time. The product was identified as hydrated zinc oxide. In the runs conducted without oxygen, the retained product curves displayed a time delay with respect to the total mass gain curves. In the presence of oxygen, however, there was practically only one chronogravimetric curve. This behaviour is interpreted on the basis of a common mechanism involving the formation of an intermediate precursor oxide, which is more readily formed in the presence of oxygen than in its absence. A set of mathematical equations was derived, from which the rate constants for both processes were obtained. The second step was ascribed to a further weak adsorption of water. This revised version was published online in July 2006 with corrections to the Cover Date.     

水与受质子溶剂氢键作用的IR研究

The interaction of water with solvents in H_2O-TBP-CCl_4 system and H_2O-p-dio-xan-CCl_4 system is studied with IR method. The absorbances of free water, 1:1 and 1:2 complex are observed and the absorbance frequencies of each species are assigned. In H_2O-TBP-CCl_4 system, there exists not only symmetric 1:2 complex but also unsymmetric one. The water molecule in unsymmetric 1:2 complex is considered to be hydrogen bonded with two kinds of oxygen atom in TBP. And the hydrogen bonds are different in strenghth. Because of diffeent spatial configurations of solvent molecules around water, more than one kind of 1:2 complex exist in H_2O-p-dioxan-CCl_4 system.     

单氢钌配合物与水和2,2,2-三氟乙醇的作用机理

利用原位¹H和³¹P NMR对单氢钌配合物TpRu(PPh₃)(CH₃CN)H [Tp＝hydrotris(pyrazolyl)borate]与H₂O和酸性HOCH₂CF₃的反应进行了研究, 结果显示相应的反应产物分别是TpRu(PPh₃)(CH₃CN)(OH) 和TpRu(PPh₃)(CH₃CN)(OCH₂CF₃). 观察到反应过程中Ru-H…HOH和Ru-H…HOCH₂CF₃分子间的氢键作用. 提出了生成TpRu(PPh₃)(CH₃CN)(OH)和TpRu(PPh₃)(CH₃CN)(OCH₂CF₃)的不同作用机理. 在水存在下, TpRu(PPh₃)(CH₃CN)H 与H₂O反应, 经过中间体TpRu(PPh₃)(H₂O)H和TpRu(PPh₃)(OH)(η²-H₂)生成产物TpRu(PPh₃)(CH₃CN)(OH). 而TpRu(PPh₃)(CH₃CN)H与酸性HOCH₂CF₃反应时, 单氢配体被质子化形成中间体[TpRu(PPh₃)(CH₃CN)- (η²-H₂)](OCH₂CF₃), 进而转变成产物TpRu(PPh₃)(CH₃CN)(OCH₂CF₃). TpRu(PPh₃)(CH₃CN)(OCH₂CF₃)与H₂作用, 经中间体TpRu(PPh₃)(HOCH₂CF₃)H生成TpRu(PPh₃)(η²-H₂)H.