Mass Spectrometry
Online ISSN : 2186-5116
Print ISSN : 2187-137X
ISSN-L : 2186-5116
特集号: Mass Spectrometry
8 巻, 2 号
Special Issue: 2nd International BMS Symposium 2018
選択された号の論文の6件中1~6を表示しています
Preface
Review
Original Article
  • Hidenori Takahashi, Yuji Shimabukuro, Daiki Asakawa, Akihito Korenaga, ...
    2020 年 8 巻 2 号 p. S0080
    発行日: 2020/01/22
    公開日: 2020/01/22
    [早期公開] 公開日: 2019/11/21
    ジャーナル オープンアクセス HTML

    Lipids, a class of biomolecules, play a significant role in the physiological system. In this study, gas-phase hydroxyl radicals (OH·) and atomic oxygens (O) were introduced into the collision cell of a triple quadruple mass spectrometer (TQ-MS) to determine the positions of the double bond in unsaturated phospholipids. A microwave-driven compact plasma generator was used as the OH·/O source. The reaction between OH·/O and the precursor ions passing through the collision cell generates product ions that correspond to the double bond positions in the fatty acyl chain. This double bond position specific fragmentation process initiated by the attachment of OH·/O to the double bond of a fatty acyl chain is a characteristic of oxygen attachment dissociation (OAD). A TQ-MS incorporating OAD, in combination with liquid chromatography, permitted a high throughput analysis of the double bond positions in complex biomolecules. It is important to know the precise position of double bonds in lipids, since these molecules can have widely different functionalities based on the position of the double bonds. The assignment of double bond positions in a mixture of eight standard samples of phosphatidylcholines (phospholipids with choline head groups) with multiple saturated fatty acyl chains attached was successfully demonstrated.

  • Tatsuya Yamamoto, Tohru Yamagaki, Honoo Satake
    2020 年 8 巻 2 号 p. S0082
    発行日: 2020/02/14
    公開日: 2020/02/15
    [早期公開] 公開日: 2019/12/18
    ジャーナル オープンアクセス HTML
    電子付録

    Hydrogen/deuterium exchange (HDX) coupled with pepsin digestion is useful for rapidly analyzing the kinetic properties of small amounts of protein. However, the analysis of HDX by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is time-consuming due to a lack of dedicated software. Currently available software programs mainly calculate average mass shifts, even though the isotopic distribution width contains information regarding multiple protein conformations. Moreover, HDX reaction samples are typically composed of peptides that contain various numbers of deuterium atoms, which also hinders the rapid and comprehensive analysis of protein dynamics. We report here on the development of a software program “Scipas DX” that can be used to automatically analyze the hydrogen–deuterium isotopic distribution in peaks in HDX spectra and calculate the average number of atoms exchanged, the average deuteration ratio, the abundance ratio for exchanged atoms, and their fitted spectra with a high degree of accuracy within a few minutes. Analysis of the abundance ratio for exchanged atoms of a model protein, adenylate kinase 1, using Scipas DX indicate that the local structure at residues 83–106 and 107–117 are in a slow equilibrium, suggesting that these regions adopt multiple conformations that are involved in the stability and in switching between the active and inactive forms. Furthermore, precise HDX kinetics of the average deuteration ratio both confirmed the known induced conformations of two regions (residues 46–75 and 131–165) that are responsible for ligand binding and verified the novel structural dynamics of residues 107–117 and 166–196 following ligand binding to ligand-binding pockets 1 and 2, respectively. Collectively, these results highlight the usefulness and versatility of Scipas DX in MALDI-MS HDX-based analyses of protein dynamics.

Technical Report
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