2018 Fiscal Year Research-status Report
Origin of Enzymes: Function and Structure of Hyperbranched Polymers
| Project/Area Number |
17K01943
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
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)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | hyperbranched polymer / polyester / wet-dry cycle / smart material / protoenzyme |
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| Outline of Annual Research Achievements |
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.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
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 The normal phase SEC technique has been replaced by the reverse phase technique in conjunction with NMR and mass-spec analyses.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.
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| Strategy for Future Research Activity |
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.
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| Causes of Carryover |
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.
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