2019 Fiscal Year Research-status Report
Energy-resolved tandem mass spectrometry for in-situ differentiation and identification of isomers
| Project/Area Number |
17K08262
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
中村 健道 国立研究開発法人理化学研究所, 環境資源科学研究センター, 特別嘱託研究員 (10360611)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Keywords | Energy-resolved MS/MS / Isomer Differentiation / CID / Ion Mobility / Collision Cross Section / Breakdown Diagram / Chemical Fingerprinting / Collision Gas Pressure |
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| Outline of Annual Research Achievements |
We've successfully developed an effective workflow for acquiring breakdown diagrams (BDs) generated by collision-induced dissociation (CID) tandem mass spectrometry (MS2) on a Waters Synapt G2 quadrupole/time-of-flight (Q-TOF) instrument in order to circumvent the limitation of utility of MS2 spectra for identification of small molecules. Despite the MS2 spectral patterns heavily depends on CID conditions including lab-frame collision energy (CE), BDs essentially reflect the whole picture of the CID pathways of each compound. Consequently, BDs become rather compound-specific (or ion-structure-specific, more precisely) pictures and confirmed to be useful for compound identification.
The potential utility of pattern-based chemical fingerprinting based on the robustness of the BDs was partly confirmed by the experiment on the Q-TOF platform with the new workflow; the appearance of BDs preserved in a reasonable range of conditions. However, preservation of the BDs' appearance has to be confirmed with other platforms. Therefore, we've run separate energy-resolved (ER) MS2 experiments on a triple quadrupole system. A Sciex 4000 QTRAP mass spectrometer was operated in a multiple reaction monitoring mode to obtain the BDs consist of major product ions from several small molecule drugs injected to the LC/MS/MS system. It turned out the appearance of BDs was preserved even the CID conditions were varied substantially by changing the collision gas (N2) pressure settings from 2 to 8, or the analyzer vacuum from 3.1 to 4.4 x 10-5 torr based on the gauge reading.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
We've originally planned to set up a computational platform for systematic search of transition states in competing fragmentation channels of small systems including protonated amino acids in gas-phase. This approach shall be incorporated to the modeling and evaluation of transition-state energy barriers of small metabolites whose molecular mass is around 100 and above. The routine task to be processed in this line of the work was planned to be assigned to a research assistant. However, in the middle of the term, the task became unable to be carried out due to illness of a team member. In the meantime, the principal investigator of the research project had become unable to fully secure the originally planned effort due to a substantially increased load of institutional tasks. It happened due to a temporally lack of human resource, i.e., an unexpected half year gap occurred before the arrival of new technical staff after the leave of old one in the beginning of the term. Due to the above reasons, we regrettably experienced some delay in the execution of the tasks and some of the planned work have to be postponed to the next year.
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| Strategy for Future Research Activity |
As we've allowed to continue the project for another year, we push forward to the original goal with some minor changes in the plan. We continue the effort to set up a computational platform for systematic search of transition states in competing fragmentation channels of small systems including protonated amino acids. However, taking into account the anticipated shortage of labor in the future, now we shift our focus a little from quantity to quality, i.e., rather than compiling a number of the compiled datasets, we put more emphasis on the automation of the method and software development for future use by the others. A limited number of modeling and evaluation of transition-state energy barriers of small metabolites will be attempted.
The method development for the data visualization shall facilitate the future application of ER-MS2 strategy and help compilation of datasets after this project. Therefore, we also plan to extend external collaborations to accelerate the development of data visualization platform. A comparison of data acquired with the Q-TOF and triple quadrupole systems suggested us the way to correct instrument factors in a reasonably simple data handling. We try to develop and to integrate a method for cross-platform standardization within the data visualization tools for future application of the method in real life applications and data compilation.
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| Causes of Carryover |
Due to the slight delay caused by the illness of a team member and temporal shortage of human resource to be assigned for carrying out the institutional tasks, some of the experiments planned for the past year became unable to be executed and had been postponed for the next year.
We plan to continue the effort for acquisition and compilation of the experimental ER-MS/MS data and theoretical data in the fiscal year 2020. Part of the leftover budget is planned to be used for purchasing additional software, hardware and chemicals for data compilation. In the meantime, the surplus fund shall be used for extending external collaborations and software development for the automation of data acquisition, processing, and software tools for the computational studies. Some part of the cost for the development of an efficient way of data visualization should be covered by the fund, as well.
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Research Products
(4 results)
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[Journal Article] An integrated screening system for the selection of exemplary substrates for natural and engineered cytochrome P450s2019
Author(s)
Kanoh Naoki, Kawamata-Asano Ayano, Suzuki Kana, Takahashi Yusuke, Miyazawa Takeshi, Nakamura Takemichi, Moriya Takashi, Hirano Hiroyuki, Osada Hiroyuki, Iwabuchi Yoshiharu, Takahashi Shunji
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Journal Title
Scientific Reports
Volume: 9
Pages: 18023
DOI
Peer Reviewed / Open Access
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