來自臺灣國立臺灣大學的Guor-Rong Her (何國榮)教授,做了題為“Comparative studies of Protein Glycosylation Using Isotope Labeling and Electrospray Ion Trap Mass Spectrometry”(應用同位素標記的電噴霧離子阱質譜比較研究蛋白的糖基化)的報告。在報告中,何教授介紹道:在糖蛋白分析中,糖蛋白往往在質譜分析前就被胰蛋白酶酶解了。而包括糖蛋白的濃度、糖基化位點、糖苷輪廓(profile)等因素,能夠解釋當發現特定的糖肽后所產生的信號的差別。課題組發展了一種分析糖蛋白的比較分析方法,能夠測定出糖蛋白的濃度、糖基化位點、糖苷輪廓的變化。這種比較分析方法應用了甲醇d0和甲醛d2的同位素標記技術,然后用微晶纖維素富集再進行質譜分析。應用該方法,用核糖核酸酶B進行了對糖蛋白濃度、糖基化位點、糖苷輪廓變化的比較分析實驗,并用ESI線性離子阱質譜進行了糖肽的測定。應用儀器具有的MS2和MS3能力,也獲得了糖基化位點和糖苷的序列。以下是英文摘要:
In the analysis of glycoprotein, glycoprotein was often digested with trypsin before MS analysis. Several causes including glycoprotein concentration, glycosylation site occupancy and glycan profile may account for the difference if the signal of a specific glycopeptides was found to be different. A strategy was proposed for comparative analyses of glycoprotein in which the change of glycoprotein concentration, the change of glycosylation site occupancy and the change of glycan profile could be differentiated. Comparative analysis was performed by stable isotope labeling using formaldehyde-d0 and formaldehyde-d2 along with cellulose microcrystalline enrichment and mass spectrometry analysis. The utility of the proposed strategy was demonstrated with ribonuclease B. The change of glycoprotein concentration was studied using samples prepared with different quantity of ribonuclease B. Level of glycosylation site occupancy was studied by mixing different ratios of ribonuclease B and ribonuclease A. The change of the site-specific glycan profile was studied by mixing ribonuclease B treated with α-mannosidase and intact ribonuclease B. ESI-MS analysis of glycopeptides was performed on a linear ion trap mass spectrometer. With the capability of MS2 and MS3 of the instrument, the site of glycosylation and the glycan sequence may also be obtained.
來自加拿大國家研究中生物科學研究所的Li, Jianjun(李建軍)教授,做了題為“Derivatization strategies for Glycomics”(糖組學的衍生方法)的報告。在報告中,李教授首先介紹了糖組學的基本概念,糖組學的目標是,系統地鑒定和表征不同糖苷的結構、功能、活性和定量等,對發現和鑒定癌細胞、體液、組織中的疾病生物標志物來說,糖組學研究是一個已被公認的創新和綜合的方法。李教授隨后介紹了課題組在糖組學研究上的新方法。比如特殊的衍生后再進行ESI-MS或MALDI-MS分析。另外,他們還發展了一種糖組學方法,來鑒定和定量復雜生物基體中的目標糖組。并獲得了很好的靈敏度和線性動態范圍。以下是英文摘要:
Glycomics is the systematic identification and characterization of diverse glycans for their structure, function, activity, and quantity. Global profiling of glycomes of cancer cells, body fluids, or tissues has been considered as an innovative and comprehensive approach to discover and identify biomarkers for various diseases. Neutralization of carboxylic acid is an important means to avoid sialic acid dissociation when sialylated oligosaccharides in presence of methylamine and (7-azabenzotriazol-1-yloxy) trispyrroli-dinophosphonium hexafluorophosphate(PyAOP). After methylamidation, sialylated oligosaccharides can be analyzed by MALDI-MS without loss of sialic acid moiety. The ESI-MS and MALDI-MS analysis of both 3’-6’-sialyllactose derivatives indicated that the quantitatively conversion of sialic acids was achieved, regardless of their linkage types under the optimal derivatization conditions.This derivatization strategy was further validated with the N-glycans released from three standard glycoproteins(Fetuin,human acid glycoprotein and bovine acid glycoprotein)containing different types of complex oligosaccharides.Using this derivatization method,the N-glycans of sera from different species(human, mouse and rat)were successfully characterized by MALDI-MS.Due to the mild reaction conditions,the modification in sialic acid residues can be retained. This improvement makes it possible to detect the sialylated oligosaccharides containing O-acetylated sialic acid moieties using MALDI-MS in positive ion mode.
In the meantime, the development of glycomics is limited by the ability to identify and quantify large numbers of glycans in complex biological samples, which is only partially achieved by current glycomics approaches. I will also present a strategy termed targeted glycomics enabling highly sensitive and consistent identification and quantification of target sets of glycans across multiple samples. The strategy was first applied to the analysis of glycans released from ribonuclease B. A linear dynamic range of three orders of magnitude (0.1-100 ng ribonuclease B ) was achieved for the detection of all five glycans. The method exhibited excellent sensitivity, evident by the detection of limit of 100attomolar for Man9Glc NAc2.The strategy was further demonstrated by characterizing the glycome of pancreas cancer cells. More than 60 N-glycans were identified and detected for about five million cells.
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美國紐約Mount Sinai 醫學院 Wang, Rong(王融)教授
來自美國紐約Mount Sinai 醫學院的Wang, Rong(王融)教授,做了題為“Fragmentation of Large Peptides Under Different Dissociation Conditions(在不同解離條件下碎裂大分子量多肽)”的報告。在報告中,王教授首先介紹了該研究的意義,了解大分子量多肽在不同碎裂條件下的碎裂性質和行為是基礎的一項工作,更重要的是,在大分子量多肽分析中研究內源性生物技術,上述研究是必要的和具有實踐意義的。課題組發展了一種系統的方法,利用化學合成的肽序列,使用不同的通用碎裂技術,以及HCD高能裂解技術,來比較多肽碎裂的效率、模式和氨基酸組成、多肽長度、電荷態、離子化方式(ESI或MALDI)之間的關系,并報告了課題組發現的結果。以下是英文摘要:
It is fundamental to understand fragmentation property and behavior of large peptides under different fragmentation conditions. More importantly, it is essential and practical in study endogenous biological techniques in analysis of large peptides. We conducted a systematical investigation of large peptide fragmentation using a chemically synthesized peptide ladders with several commonly used fragmentation techniques, and high energy collision induced dissociation. Peptide fragmentation efficiency and pattern were tested against amino acid composition, peptide length, and charge stage, as well as different ionization methods, e.g. electrospray ionization and matrix assistant laser desorption ionization. Detailed experimental findings will be reported.
來自美國PerkinElmer公司的Shen, Shida(沈世達)高級研究員,做了題為“A High Resolving Power and Mass Accuracy Time-Of-Flight MS for Rapid Detection and Identification of Microorganisms”(用高分辨率高質量精度的飛行時間質譜快速測定微生物)的報告。在報告中,沈研究員介紹了公司研發的具有精確質量測定的ESI TOF質譜,可快速鑒定病原體和進行品系分類。這種獨特的方法可以每個樣品30秒的速度鑒定微生物,在針對生物戰攻擊或新傳染病自然爆發時具有潛力。該方法使用了一種高端、低成本的ESI TOF質譜,報告介紹了該質譜儀在精確質量測定、高分辨和24小時穩定性方面的性能,并用豬流感病毒H1N1作為實例,闡述了檢測和鑒定微生物的步驟。以下是英文摘要:
An exact mass measurement ESI TOF mass spectrometer has been developed for fast pathogen identification and strain typing. This unique technology relies on mass spectrometry-derived base composition signatures of amplicons from PCR (Polymerase Chain Reaction) products, and “intelligent PCR primers” that target broadly conserved regions of microbial genomes that flank variable regions. This rapid detection (30 seconds per sample) and identification of microorganism methodology also associates with a potential biological warfare attack or a natural outbreak of an emerging infectious disease.
The strategy to build a high end and low cost ESI TOF machine will be discussed. The performance data particularly in accurate mass measurement, high resolving power and 24 hours stability test will be presented. The discovery of Swine flu virus H1N1 will be presented as an example to illustrate the procedure of detection and identification of microoganisims.
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美國北卡大學Chaple Hill醫學院 Chen, Xian(陳先)教授
來自美國北卡大學Chaple Hill醫學院的 Chen, Xian(陳先)教授,做了題為“Systems Dissection of Signal Transduction by Using Quantitative Proteomics”(用定量蛋白質組方法系統剖析信號傳導)的報告,在報告中,陳教授主要介紹了課題組利用同位素標記的方法,進行蛋白質組學定量研究的方法。
芝加哥大學 Zhao, Yingming(趙英明)教授
來自芝加哥大學的Zhao, Yingming(趙英明)教授做了題為“Discovery of Novel Biochemical Pathways Using Proteomics Approaches”(使用蛋白質組學方法發現新的生化路徑”的報告。在報告中,趙教授談到,很多對于組蛋白和p53的研究顯示,這些蛋白可能會存在一系列的翻譯后修飾,而這些修飾的大多數和重要的生物功能相關。然而除了對于已被廣泛研究的幾個蛋白,在其它蛋白中,翻譯后修飾的類型和修飾的位點還有很多是未知的。對信息的缺乏暗示了一種對于可靠的表征蛋白中所有的翻譯后修飾及動態變化的迫切需求。該課題組最近發展了一種非限制的蛋白序列校準算法,PTMap,并用它配合質譜一起用于所有可能的翻譯后修飾的測定,不管是已知的還是以前從未發表過的。使用這種算法,課題組鑒定了新型的翻譯后修飾,發現常見的體外蛋白修飾,研究了翻譯后修飾的交叉污染和蛋白的突變。以下是英文摘要:
Extensive studies in histones and p53 suggest that these proteins can be modified by an array of protein post-translational modifications(PTMs), most of which are correlated with important biological functions. Nevertheless, PTM types and their sites in other proteins remain largely unknown, except several widely studied ones. The information deficiency suggests an urgent need for reliable technology for characterization of all the PTMs in a protein and for their dynamic studies. To this end, we recently developed an unrestrictive protein sequence alignment algorithm, PTMap, and used it in conjunction with mass spectrometry for accurate identification of all the possible PTMs, known or undescribed ones. We have used the algorithm to identify novel PTMs, to discover common in vitro protein modifications, to study PTM cross-talks, and to study protein mutations. In this presentation, applications of such mass spectromety-based proteomics technologies will be discussed.
臺灣國立Chung Hsing大學 Maw-Rong Lee(李茂榮)教授
來自臺灣國立Chung Hsing大學的Maw-Rong Lee(李茂榮)教授,做了題為“Functionalized Nanoparticles Assisted Desorption Electrospray Ionization for Determination of Ultraviolet Absorbers in Urine”(用功能納米粒子輔助解吸電噴霧技術測定尿中的紫外線吸收劑)的報告,該課題組用實驗室自制的絲網印刷的銀板或石墨板,進行高電壓下的電噴霧,并介紹了課題組使用的紫外線吸收劑的提取過程。經過提取,用溶劑從磁性粒子NPs上提取出分析物。提取物或未解吸的磁性粒子NPs被滴在絲網上印刷,來評估離子化效率。實驗結果顯示,該納米粒子可以提高信號強度縮短分析時間。說明功能納米粒子輔助解吸電噴霧技術可在痕量分析中增強專一性并提高通量。以下是英文摘要:
Functionalized nanoparticles assisted desorption electrospray ionization for analysis of ultraviolet absorbers in urine was developed. The electrospray was performed with high voltage on a laboratory-made screen-printed plate with silver or graphite. In this study, the ultraviolet absorbers including 3-(4-methylbenzylidene)-camphor (4-MBC),2-ethyl-4-(dimethylamino)-benzoate(O-PABA)AND 2-hydroxy-4-(octyloxy)-benzophenone(BP-12) were extracted with iron oxide-coated silicon dioxide nanoparticles as the affinity adsorbent. After extraction, the analytes were isolated from magnetic NPs with solvent. The extract or the magnetic NPs without desorption was dipped on the screen-printed to evaluate the effect on the ionization efficiency. From the results, the nanoparticles can enhance the intensity of the signal detected and short the analytical time. This technique demonstrates that the nanoparticles assisted desorption electrospray ionization offers a high specific and high throughput screening for trace analysis.