2007 Fiscal Year Final Research Report Summary
Precise Analyses on the Enzymes Participationg in Fundamental Pathways in the Biosynthesisi of Isoprenoids
| Project/Area Number |
17310122
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Living organism molecular science
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| Research Institution | Tohoku University |
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Principal Investigator |
KOYAMA Tanetoshi Tohoku University, Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Professor (20089808)
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| Co-Investigator(Kenkyū-buntansha) |
NOIKE Motoyoshi Institute of Multidisciplinary Research for Advanced Materials, 多元物質科学研究所, Assistant Professor (20420010)
TAKAHASHI Seiji Institute of Multidisciplinary Research for Advanced Materials, 多元物質科学研究所, Assistant Professor (90343061)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Isoprenoid Biosynthesis / Prenyltransferase / Natural Rubber Biosynthesis Farnesyl Diphosphate / Prenyl Chain Elongating Enzyme / Undecaaprenyl Diphosphate / Farnesyl Diphosphate / Dolichol |
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| Research Abstract |
[Studies on the Prenyl Chain Determination Mechanism of cis-Prenyltransferases] The ultimate chain length determination mechanism of cis-prenyl diphosphate syntheses was uncovered through structural manupulation of undecaprenyl diphosphate synthase derived from Micrococcus luteus B-P 26, based on comparisons between structures of various cis-prenyltransferases. Amino acid residues located in proximity of the substrate binding site as well as the charged residues inserted into the helix-III region are very important for the chain length determination mechanisms.
[Studies on the Substrate Binding Mechanisms of Prenyl Chain Elongating Enzymes] The methyl group at the 3-position of allylic substrates for prenyl chain elongating enzymes is found to be very important for the catalytic function as well as the substrate recognition mechanisms. According to the data on X-ray crystal structure determination analysis of undecaprenyl diphosphate synthase, three meta-stable structures, open-, medium-, and dosed forms of the helix-III area were found to be present, suggesting that this structural change makes the flexibility of helix -III to continue the chain elongation reaction repeatedly in the polyprenyl chain elongating prenyltransferase reaction.
[Studies on the Biosynthesis of Natural Rubber] Washed small rubber particles prepared by gel filtration of fresh Hevea brasiliensis, latex was found to have high rubber transferase activity when isopentenyl diphosphate and an allylic substrate were present in the reaction mixture. The enzymatic ally synthesized rubber molecule showed a typical bimodal molecular weight distribution pattern in gel permeation chromatography analysis, which was similar to those of the endogenous rubber with peaks at around 10^6 and 10^5.
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