| Project/Area Number |
08044205
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Osaka University |
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Principal Investigator |
SAKIYAMA Fumio Institute for Protein Research, Osaka University, Professor, 蛋白質研究所, 教授 (40029947)
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| Co-Investigator(Kenkyū-buntansha) |
李 紹良 大阪大学, 蛋白質研究所, 助手 (40252720)
SATO Mamoru Faculty fo Science, Yokohama City University, Professor, 理学部, 教授 (60170784)
NORIOKA Shigemi Institute for Protein Research, Osaka University, Associate Professor, 蛋白質研究所, 助教授 (70198638)
CLARKE A.E School of Botany, Melbourne University, Professor, 植物学部, 教授
LI Shao-liang Institute for Protein Research, Osaka University, Assistant Professor
NEWBIGIN Edw メルボルン大学, 植物学部, 上席研究員
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| Project Period (FY) |
1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Self-incompatibility / Ribonuclease / S-RNase / Tobacco / Nicotiana alata / Tertiary Structure / リボヌクレアーゼ |
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| Research Abstract |
Many species of flowering plants have a self-incompatibility system which recognizes self or non-self between a pistil and pollen (tube) after pollination and which suppresses the growth of the self-pollen tube to prevent self-fertilization. Gametophytic self-incompatibility (GSI) is controlled genetically by a single locus (S-locus) with multiple alleles. When the haploid S-allele of the pistil, pollen tube growth is arrested within the style. In solanaceous and rosaceous plants, pistil glycoproteins that cosegregate with S-alleles have been identified as a ribonuclease of the RNaseT_2 family (S-RNase). S-RNase was confirmed to be necessary for GSI both in transformation experiments with sense and antisense S-RNase genes in solanaceous species and by analysis of the self-compatible mutant of Japanese per. How S-RNase functions in the discrimination between self-and non-self-pollen and in the inhibition of pollen tube growth has yet to be established. The purpose of this study is to analyze X-ray crystal structures of solanaceous and rosaceous S-RNases and to clarify these tertiary structures.
Fifty mg of tobacco S_1-RNase were purified from 10,000 flowers and were used for crystallization. This protein was crystallized by the hanging drop method. After screening 150 kinds of the crystallization conditions, we found the best one ; PEG-6000 as a precipitant, pH 6.0,12mg/ml protein concentration. The crystal was monoclonic ; P21, a=80.3 *, b=77.9 *, c=68.3 *, beta=90.0ﾟ. This crystal was found to be available for tertiary structure analysis. We are now trying to soak heavy metals into the crystal.
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