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2018 年度 実施状況報告書

原始酵素の起源:多分岐ポリマー複合体の合成と触媒活性評価

研究課題

研究課題/領域番号 17K01943
研究機関東京工業大学

研究代表者

ママジャノフ イリーナ  東京工業大学, 地球生命研究所, 特任教授 (80776261)

研究期間 (年度) 2017-04-01 – 2020-03-31
キーワードhyperbranched polymer / polyester / wet-dry cycle / smart material / protoenzyme
研究実績の概要

Hyperbranched polyesters (HBPE) that are the subject oh this study tend to undergo gelation at certain configurations and molecular weights. We have discovered that the onset of gelation is delayed when polyesterification system is exposed to wet-dry cycling. We have discovered that these conditions not only help control the size of the HBPE but also the relative stoichiometry of monomeric units. This implies that environmental cycles on prebiotic Earth could have assisted in the selective synthesis of HBPE and their maintenance in water solution. Paper on the subject has been recently submitted. As a part of our work on the construction of proto-enzymes, we have synthesized prebiotically plausible metal sulfide-HBPE nanoparticle systems as possible precursors to extant enzymes bearing metal sulfide clusters. We have further compared the function of HBPE system to commercial nanoparticles and supports to show superiority of the HBPE complexes. The broader impact of the study is that stable nanoparticle supports can be synthesized straightforwardly from inexpensive and environmentally benign compounds. The study focused on citric acid and glycerol, but could be extended to other biodegradable acids and alcohols. The manuscript is currently under preparation.

現在までの達成度 (区分)
現在までの達成度 (区分)

2: おおむね順調に進展している

理由

We have previously reported on the difficulties in the analysis of the heterogeneous systems. The issues has been addressed.
1) The difficulties in the size-exclusion chromatography (SEC) have been resolved . The normal phase SEC technique has been replaced by the reverse phase technique in conjunction with NMR and mass-spec analyses.
2) We have developed protocols for the analyses of heterogeneous systems that involves multiple spectroscopic techniques and bulk measurements. We have started a collaboration with machine learning specialists to further this branch of analytics.

今後の研究の推進方策

We will study the transition from HBPE-based catalysts towards more familiar peptide-based catalysts. This was done by introducing amino acids into the ester systems during the polymerization process and invoking transamidation reactions. We hypothesize that transamidation of HBPE into linear depsipeptides would imprint some of the polyester properties into the newly formed polymers, i.e. the insertion of amino acids into the branched scaffold would not be random. The hydrophobic amino acids would incorporate into the r core of the HBPE, while polar amino acids would remain on the periphery. The structure determination, sequencing and stability studies would be performed using NMR spectroscopy, SEC and mass spectrometry. The catalytic functions will also be assessed by functional assays.

次年度使用額が生じた理由

We have incurred 613,794 JPY to be incurred this year. This sum was set aside for an international conference presentation and for open access publication fees.
1) We have a manuscript submitted to an open access journal, however the review process was not finished in FY 2018, but spilled over into FY 2019. For this reason we have transferred 200,000 JPY into this year's budget.
2) We have originally planned to use approximately 400,000 JPY for a presentation at an international conference in the FY 2018. However, in September 2018 Irena Mamajanov has received an invitation to present at the prestigious Goldschmidt conference that would take place in FY 2019. We have decided to transfer the funds set aside for travel to this year's budget to be able to present the results funded by this grant at Goldschmidt in Barcelona Spain.

  • 研究成果

    (5件)

すべて 2019 2018

すべて 雑誌論文 (3件) (うち国際共著 3件、 査読あり 2件、 オープンアクセス 3件) 学会発表 (2件) (うち国際学会 1件、 招待講演 2件)

  • [雑誌論文] Wet-dry Cycling Delays the Gelation of Hyperbranched Polyesters: Implications to the Origin of Life2019

    • 著者名/発表者名
      Irena Mamajanov
    • 雑誌名

      Preprints

      巻: N/A ページ: 2019040297

    • DOI

      doi: 10.20944/preprints201904.0297.v1

    • オープンアクセス / 国際共著
  • [雑誌論文] Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries2018

    • 著者名/発表者名
      Kuhan Chandru, Nicholas Guttenberg, Chaitanya Giri, Yayoi Hongo, Christopher Butch, Irena Mamajanov & H. James Cleaves II
    • 雑誌名

      Communications Chemistry

      巻: 1 ページ: 30

    • DOI

      https://doi.org/10.1038/s42004-018-0031-1

    • 査読あり / オープンアクセス / 国際共著
  • [雑誌論文] Selective Synthesis of Hyperbranched Polyesters under Wet-Dry Cycling Conditions2018

    • 著者名/発表者名
      Irena Mamajanov
    • 雑誌名

      ALife

      巻: 2018 ページ: 580-581

    • DOI

      https://doi.org/10.1162/isal_a_00107

    • 査読あり / オープンアクセス / 国際共著
  • [学会発表] From Messy Chemistry to the Origins of Life2019

    • 著者名/発表者名
      Irena Mamajanov
    • 学会等名
      IISER Pune. Special mini-symposium on the origin of life
    • 招待講演
  • [学会発表] Rocks to Life: Messy Chemistry Approach to Evolution2018

    • 著者名/発表者名
      Irena Mamajanov
    • 学会等名
      ALife 2018. Special workshop: Earth, Life and ALIFE
    • 国際学会 / 招待講演

URL: 

公開日: 2019-12-27  

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