| Project/Area Number |
13640553
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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 |
Inorganic chemistry
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| Research Institution | Ibaraki University |
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Principal Investigator |
KOHZUMA Takamitsu Ibaraki University, College of Science, Associate Professor, 理学部, 助教授 (50215183)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Metalloprotein / Copper Protein / Molecullar Recognition / Pseudoazurin / Plastocyanin / UV Resonance Raman / 金属蛋白質 / 弱い相互作用 / ブルー銅蛋白質 / スタッキング / 常磁性NMR / 紫外共鳴ラマンスペクトル / 銅蛋白質 |
|---|
| Research Abstract |
The UV resonance Raman spectrum of pseudoazurin gives a copper coordinated histidine imidazole band at 1385 cm^<-1>. A characteristic histidine imidazolium Raman band at 1408 cm^<-1> is detected in the UVRR spectrum of Cu(I) pseudoazurin at acidic pH. This supports the protonation of the His81 ligand in the reduced protein at low pH values. The imidazolium Pseudoazurin substituted with Zn^<2+> gave characteristic Raman Bands for the metal ion coordinated imidazole at 1388 cm^<-1> at neutral pH. The histidine imidazole band diminishes in intensity in Zn^<2+> pseudoazurin upon lowering the pH. In all of the metal-substituted pseudoazurins an imidazolium band at 1408 cm^<-1> appears at pH < 4.0. Pseudoazurin substituted with Zn^<2+>, Cd^<2+>, and Ni^<2+> give very similar pH dependence of their X-Pro Raman bands as apo-pseudoazurin. These findings indicate that the metal ion is released from the active site of Zn^<2+>, Cd^<2+>, and Ni^<2+> pseudoazurin at acidic pH accompanied by a change in the protein's secondary structure. This behavior is clearly absent in both the Cu(I) and CU(II) proteins indicating that pseudoazurin discriminates between copper and the other metal ions studied.
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