| Project/Area Number |
18570107
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | Hiroshima University |
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Principal Investigator |
GEKKO Kunihiko Hiroshima University, Graduate School of Science, Emeritus Professor (10023467)
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| Co-Investigator(Kenkyū-buntansha) |
OHMAE Eiji Hiroshima University, Graduate School of Science, Assistant Professor (30284152)
松尾 光一 広島大学, 放射光科学研究センター, 講師(研究機関研究員) (40403620)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥4,020,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | synchrotron / vacuum-ultraviolet cirvular dichroism / proteins / denatured state / secondary-structure analysis / amino-acid sequence |
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| Research Abstract |
We constructed the vacuum-ultraviolet circular dichroism (VUVCD) spectrophotometer at Hiroshima University Synchrotron Radiation Center. This spectrophotometer was applied for the secondary-structure analyses of proteins as follows.
1. Secondary-structure analysis of denatured proteins: The VUVCD spectra down to 172 nm in various solvent conditions revealed the considerable amount of secondary structures remaining in the acid-, cold-, heat-, and guanidine-hydrochloride-denatured states of metmyoglobin, staphylococcal nuclease, and thioredoxin. However, the alcohol-denatured states induced by trifluoroethanol and methanol involved a large amount (70%) of α-helix, different from other denatured states.
2. Sequence-based prediction of secondary structures: The sequence-based prediction of secondary structures was improved up to 75% accuracy by combining the neural network method with the contents and numbers of a-helix and 3-strand obtained from the VUVCD data of 30 proteins down to 160 nm.
… More
VUVCD data could enhance the predictive accuracy to over 80% when combined with the currently best sequence-predictive algorithms.
3. Secondary-structure analysis of protein interacting with lipid: When bound with phospholipid, α-acid-glycoprotein increased the content of α-helix from 11% (2 segments) to 50% (7 segments) and that of β-strand from 40% (11 segments) to 10% (4 segments). These structure changes occurred mainly at the ligand-binding sites, indicating important role of membrane interaction in protein function.
4. Secondary-structure analysis of protein in amyloid: The VUVCD spectra of β_2-microglobulin and its two peptide segments (#21-31, #21-29) down to 175 nm revealed the formation of characteristic β-sheet structures. The details of the amyloid structure are under theoretical analysis.
These results demonstrate that synchrotron-radiation VUVCD spectroscopy gives new and detailed information on the protein secondary structures, greatly expanding its applicability to protein structural biology. Less
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