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1.
Mass spectrometry has grown in recent years to a well-accepted and increasingly important complementary technique in structural biology. Especially electrospray ionization mass spectrometry is well suited for the detection of non-covalent protein complexes and their interactions with DNA, RNA, ligands, and cofactors. Over the last decade, significant advances have been made in the ionization and mass analysis techniques, which makes the investigation of even larger and more heterogeneous intact assemblies feasible. These technological developments have paved the way to study intact non-covalent protein-protein interactions, assembly and disassembly in real time, subunit exchange, cooperativity effects, and effects of cofactors, allowing us a better understanding of proteins in cellular processes. In this review, we describe some of the latest developments and several highlights.  相似文献   

2.
In the last decade, the demand for high-throughput DNA analysis methods has dramatically increased, mainly due to the advent of the human genome sequencing project that is now nearing completion. Even though mass spectrometry did not contribute to that project, it is clear that it will have an important role in the post-genome sequencing era, in genomics and proteomics. In genomics, mainly matrix-assisted laser desorption/ionization (MALDI) mass spectrometry will contribute to large-scale single nucleotide polymorphism (SNP) genotyping projects. Here, the development and history of DNA analysis by mass spectrometry is reviewed and put into the context with the requirements of genomics. All major contributions to the field and their status and limitations are described in detail.  相似文献   

3.
Lignin, a resistant cell-wall constituent of all vascular plants that consists of ether and carbon-linked methoxyphenols, is still far from being structurally described in detail. The main problem in its structural elucidation is the difficulty of isolating lignin from other wood components without damaging lignin itself. Furthermore, the high number and variegated forms of linkages that occur between the monomeric units and the chemical resistance of certain ether bonds limit the extent to which analytical and degradation procedures can be used to elucidate the lignin structure. Most of our present knowledge about the molecular structure of lignin is based on the analysis of monomers, dimers or, at the most, tetramers of degraded isolated lignins. Mass spectrometry (MS), which offers advantages in terms of speed, specificity, and sensitivity, has revealed to be a very powerful technique in the structural elucidation of lignins, in combination with the great number of chemical and thermal degradation methods available in the study of lignin. Moreover, the recent development of new ionization techniques in MS-electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization (MALDI)-MS-has provided new possibilities to also analyze the undegraded lignin macromolecule.  相似文献   

4.
    
Since our last comprehensive review on multi-dimensional mass spectrometry-based shotgun lipidomics (Mass Spectrom. Rev. 24 (2005), 367), many new developments in the field of lipidomics have occurred. These developments include new strategies and refinements for shotgun lipidomic approaches that use direct infusion, including novel fragmentation strategies, identification of multiple new informative dimensions for mass spectrometric interrogation, and the development of new bioinformatic approaches for enhanced identification and quantitation of the individual molecular constituents that comprise each cell's lipidome. Concurrently, advances in liquid chromatography-based platforms and novel strategies for quantitative matrix-assisted laser desorption/ionization mass spectrometry for lipidomic analyses have been developed. Through the synergistic use of this repertoire of new mass spectrometric approaches, the power and scope of lipidomics has been greatly expanded to accelerate progress toward the comprehensive understanding of the pleiotropic roles of lipids in biological systems.  相似文献   

5.
头孢菌素类抗生素的电喷雾多级串联质谱分析   总被引:5,自引:0,他引:5  
采用电喷雾多级串联质谱技术,对头孢呋辛、头孢噻吩钠、头孢硫脒、头孢噻利、头孢西丁钠五种头孢菌素类抗生素进行了系统研究,总结了该类化合物的电喷雾质谱特征断裂机理。该类化合物在电喷雾正离子或负离子模式下,均发生C-3位侧链C-X(X=O、N、S)键的特征断裂,为头孢菌素类抗生素化合物结构鉴定提供了新方法。在负离子模式下,头孢呋辛二级质谱中β-内酰胺环发生开环断裂,与文献结果一致;在电喷雾正离子模式下,头孢噻吩钠、头孢噻利、头孢西丁钠多级串联质谱中均失去C-7位侧链上一分子CO。  相似文献   

6.
用于美沙芬快速检测的电喷雾离化离子迁移率谱技术研究   总被引:1,自引:0,他引:1  
中枢性镇咳药物美沙芬在大剂量使用情况下会出现类似毒品的迷幻效果,近年来在不少国家及地区出现滥用趋势.文中对用于美沙芬快速检测的电喷雾离化离子迁移率谱技术(ESI-IMS)进行研究,优化了ESI-IMS系统样品流量、电喷液成分和漂移管温度等工作参数,实现美沙芬的快速高灵敏检测,其约化迁移率为1.23 cm2/Va,基于三倍噪声计算的检测限为~40 μg/L.利用纯中药止咳片剂验证了ESI-IMS系统对实际样品中美沙芬检测的可行性.  相似文献   

7.
乌头碱类生物碱的质谱研究进展   总被引:11,自引:2,他引:9  
王勇  刘淑莹 《质谱学报》2002,23(2):112-112
本文简述质谱方法在乌头碱型 C19二萜生物碱的分析和结构鉴定等方面的应用以及不同电离方式下乌头碱的断裂行为 ,并总结我们近来利用电喷雾串联质谱技术分析几种乌头属植物中生物碱的研究结果 ,提出脂类生物碱 ( lipo-alkaloids)存在于其它乌头属植物中的可能性  相似文献   

8.
通关藤中甾体化合物的电喷雾质谱裂解规律研究   总被引:1,自引:0,他引:1  
利用电喷雾串联质谱(ESI-MSn)研究从云南产通关藤(Marsdeniatenacissi ma(Roxb.)Wight et Arn)中分离纯化得到的19种甾体化合物的裂解规律,分析了它们从分子离子出发的多级质谱的裂解碎片,主要报道了tenacigenoside B,tenacigenoside G,tenacigenoside H在ESI正离子模式下[M+Na]+的裂解途径和碎片离子峰,结合其他16种化合物的裂解实验,说明这些甾体化合物主要丢失C-11和C-12位上的取代基,其次是糖苷上糖顺序断裂。这有助于依据此类化合物结构特点和裂解规律来推断其结构,为此类化合物的快速鉴定提供依据。n  相似文献   

9.
Protein identification by tandem mass spectrometry (MS/MS) is key to most proteomics projects and has been widely explored in bioinformatics research. Obtaining good and trustful identification results has important implications for biological and clinical work. Although well matured, automated software identification of proteins from MS/MS data still faces a number of obstacles due to the complexity of the proteome or procedural issues of mass spectrometry data acquisition. Expected or unexpected modifications of the peptide sequences, polymorphisms, errors in databases, missed or non-specific cleavages, unusual fragmentation patterns, and single MS/MS spectra of multiple peptides of the same m/z are so many pitfalls for identification algorithms. A lot of research work has been carried out in recent years that yielded new strategies to handle a number of these issues. Multiple MS/MS identification algorithms are now available or have been theoretically described. The difficulty resides in choosing the most adapted method for each type of spectra being identified. This review presents an overview of the state-of-the-art bioinformatics approaches to the identification of proteins by MS/MS to help the reader doing the spade work of finding the right tools among the many possibilities offered.  相似文献   

10.
地球科学中热电离质谱法的进展   总被引:6,自引:0,他引:6  
对应用于地球科学领域的几种热电离质谱新方法的进展进行了综述,包括Sr、Nd同位素稀释分析的分馏校正、Re—Os负离子质谱法、热电离质谱铀系法、B、Cl稳定同位素测定及La—Ce法。  相似文献   

11.
Hydrogen exchange coupled to mass spectrometry (MS) has become a valuable analytical tool for the study of protein dynamics. By combining information about protein dynamics with more classical functional data, a more thorough understanding of protein function can be obtained. In many cases, protein dynamics are directly related to specific protein functions such as conformational changes during enzyme activation or protein movements during binding. The method is made possible because labile backbone hydrogens in a protein will exchange with deuterium atoms when the protein is placed in a D2O solution. The subsequent increase in protein mass over time is measured with high-resolution MS. The location of the deuterium incorporation is determined by monitoring deuterium incorporation in peptic fragments that are produced after the labeling reaction. In this review, we will summarize the general principles of the method, discuss the latest variations on the experimental protocol that probe different types of protein movements, and review other recent work and improvements in the field.  相似文献   

12.
Photochemical cross-linking is a commonly used method for studying the molecular details of protein-nucleic acid interactions. Photochemical cross-linking aids in defining nucleic acid binding sites of proteins via subsequent identification of cross-linked protein domains and amino acid residues. Mass spectrometry (MS) has emerged as a sensitive and efficient analytical technique for determination of such cross-linking sites in proteins. The present review of the field describes a number of MS-based approaches for the characterization of cross-linked protein-nucleic acid complexes and for sequencing of peptide-nucleic acid heteroconjugates. The combination of photochemical cross-linking and MS provides a fast screening method to gain insights into the overall structure and formation of protein-oligonucleotide complexes. Because the analytical methods are continuously refined and protein structural data are rapidly accumulating in databases, we envision that many protein-nucleic acid assemblies will be initially characterized by combinations of cross-linking methods, MS, and computational molecular modeling.  相似文献   

13.
The determination of disulfide bonds is an important aspect of gaining a comprehensive understanding of the chemical structure of a protein. The basic strategy for obtaining this information involves the identification of disulfide-linked peptides in digests of proteins and the characterization of their half-cystinyl peptide constituents. Tools for disulfide bond analysis have improved dramatically in the past two decades, especially in terms of speed and sensitivity. This improvement is largely due to the development of matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), and complementary analyzers with high resolution and accuracy. The process of pairing half-cystinyl peptides is now generally achieved by comparing masses of non-reduced and reduced aliquots of a digest of a protein that was proteolyzed with intact disulfide bonds. Pepsin has favorable properties for generating disulfide-linked peptides, including its acidic pH optimum, at which disulfide bond rearrangement is precluded and protein conformations are likely to be unfolded and accessible to cleavage, and broad substrate specificity. These properties potentiate cleavage between all half-cystine residues of the substrate protein. However, pepsin produces complex digests that contain overlapping peptides due to ragged cleavage. This complexity can produce very complex spectra and/or hamper the ionization of some constituent peptides. It may also be more difficult to compute which half-cystinyl sequences of the protein of interest are disulfide-linked in non-reduced peptic digests. This ambiguity is offset to some extent by sequence tags that may arise from ragged cleavages and aid sequence assignments. Problems associated with pepsin cleavage can be minimized by digestion in solvents that contain 50% H(2) (18)O. Resultant disulfide-linked peptides have distinct isotope profiles (combinations of isotope ratios and average mass increases) compared to the same peptides with only (16)O in their terminal carboxylates. Thus, it is possible to identify disulfide-linked peptides in digests and chromatographic fractions, using these mass-specific markers, and to rationalize mass changes upon reduction in terms of half-cystinyl sequences of the protein of interest. Some peptides may require additional cleavages due to their multiple disulfide bond contents and/or tandem mass spectrometry (MS/MS) to determine linkages. Interpretation of the MS/MS spectra of peptides with multiple disulfides in supplementary digests is also facilitated by the presence of (18)O in their terminal carboxylates.  相似文献   

14.
牛膝中三萜皂苷类化合物的电喷雾电离串级质谱研究   总被引:1,自引:1,他引:0  
采用大孔树脂柱层析分离方法分离提取牛膝 (Achyranthesbientata BI)中的三帖皂苷类化合物。通过相对分子质量及电喷雾电离多级串连质谱 (ESI-MSn)技术分别对牛膝提取物中的有效成分牛膝皂苷 (相对分子质量 95 6)、牛膝皂苷 (相对分子质量 794)进行定性分析 ,并提出了其电喷雾质谱碎裂机理。该方法样品处理简单 ,分析速度快且灵敏度高 ,适用作为牛膝有效成分三萜皂苷类物质鉴定的依据。  相似文献   

15.
In the 20 years, since the introduction of electrospray mass spectrometry (ESI-MS), the use of this technique in various fields of inorganic, organometallic, and analytical chemistry has been steadily increasing. In this study, the application of ESI-MS to the study of metal-ligand solution equilibria is reviewed (till 2004 included). In a first section, advantages and drawbacks of ESI-MS in this type of application are described. Subsequently, a list of ca. 300 studies is reported, in which ESI-MS was used to give number and stoichiometry of the species at equilibrium, or also to estimate their stability constants. All studies are classified according to the metal ions under examination. Other related applications, such as host-guest interactions and metal ion-protein binding studies, are briefly reviewed as well.  相似文献   

16.
溶剂的组成影响电喷雾离子(ESI)化效率。该研究观察了ESI溶剂体系中不同浓度的乙腈(ACN)对MRFA、Reserpine、ΜLtramark1621、马肌球蛋白酶切肽段等标准物质的质谱信号响应强度的影响,发现在溶剂体系中,ACN浓度达到70%时,上述物质的质谱信号强度具有最大值。根据这一现象, 对传统的反相色谱-电喷雾-质谱(RPLC-ESI-MS)系统进行管路改造,在分析柱后通过1个三通阀引入适当流速的有机溶剂进行辅助喷雾。对马心肌蛋白酶切肽段混合物的分析表明,该方法可以有效提高酶切肽段的检出率,并提高鉴定蛋白质的序列覆盖率。  相似文献   

17.
电喷雾质谱(ESI-MS)因具有灵敏度高、响应速度快、分辨率高、原位在线监测等特点,广泛应用于反应监测领域。本文主要从不同离子化技术角度,综述了电喷雾质谱在反应监测和机理研究方面的进展。重点介绍了在线电喷雾质谱技术,其中包括解吸附电喷雾离子化质谱(DESI-MS)、萃取电喷雾离子化质谱(EESI-MS)、纳升电喷雾离子化质谱(nESI-MS)、超声喷雾离子化质谱(SSI-MS)以及其他在线电喷雾离子化质谱在反应监测中的应用。最后,对电喷雾质谱在反应监测的发展趋势进行总结和展望。  相似文献   

18.
采用电喷雾离子阱多级质谱技术(ESI-MSn)在正离子模式下(ESI+)对食品中常见的几种非法添加工业染料碱性橙21、22和罗丹明B进行裂解规律探析。分析了这3种染料从分子离子出发的多级质谱裂解碎片,发现此类化合物容易先失去Cl-,形成N+离子;在电离源的轰击下,容易失去·CH3和·CH2CH3;并且探析了碱性橙21、22和罗丹明B的多级质谱裂解规律。该质谱裂解规律有助于推断碱性工业染料及其类似物的结构特点和裂解规律,为此类化合物的快速鉴定提供依据。  相似文献   

19.
描述了应用电喷雾二级串联质谱的撞击能量差别来确定不同骨架的二萜生物碱的方法。在优化质谱条件后 ,分析 9个绣线菊二萜生物碱裂解途径。结果表明 :Hetisine型二萜生物碱二级裂解比 Atisine型二萜生物碱二级裂解所需的能量高 ,因此可以用电喷雾二级串联质谱的撞击能量差别来简便快速地鉴定粉花绣线菊不同变种中二萜生物碱的结构类型  相似文献   

20.
傅里叶变换离子回旋共振质谱的最新进展和展望   总被引:1,自引:0,他引:1  
对傅里叶变换离子回旋共振(FT-ICR)质谱的基本原理进行了简要介绍,从离子回旋频率、回旋半径、离子速度、离子能量等几个方面阐明其基本概念,阐述了离子激发、检测原理.对离子同旋共振质谱与近年来新兴的常压离子化技术联用的最新进展进行了评述,对其发展趋势进行展望.由于常压离子化技术能够将复杂样品进行直接离子化,无需样品预处理或只需少量样品处理过程,常压离子化方法与FT-ICR质谱的联用必将拓宽其应用领域并成为质谱技术研究的新热点.  相似文献   

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