| Project/Area Number |
17570133
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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 |
Biophysics
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| Research Institution | Kyoto University (2006)
Nara Institute of Science and Technology (2005) |
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Principal Investigator |
IMAMOTO Asushi Kyoto Univ., Grad. Sch. of Sci., Associate professor, 大学院理学研究科, 助教授 (80263200)
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| Co-Investigator(Kenkyū-buntansha) |
KATAOKA Mikio NAIST, Grad. Sch. of Materials Sci., Professor, 物質創成科学研究科, 教授 (30150254)
KAMIKUBO Hironari NAIST, Grad. Sch. of Materials Sci., Assist. Professor, 物質創成科学研究科, 助教授 (20311128)
YAMAZAKI Yoichi NAIST, Grad. Sch. of Materials Sci., Assist. Professor, 物質創成科学研究科, 助教授 (40332770)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | CH / p interaction / O interaction / PYP / Photoreceptor protein / Photocycle / Hydrophobic interaction / Hydrogen bond / Structural change / CH…O相互作用 / π…π相互作用 / 疎水的相互作用 / 光反応 |
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| Research Abstract |
Weak intramolecular interactions such as CH/O and CH/π interactions are recently proposed to be important for biomolecules, while they are several times weaker than the conventional OH/O and NH/O hydrogen bonds. In the present study, the role of these weak interactions was studied using photoactive yellow protein (PYP). The characterization of PYP mutants demonstrated that the thermal stability and photocycle rate constant of PYP are largely reduced for the mutants which lack aromatic ring at 6 position or alkyl chain at 123 position. This effect is much larger than the mutagenesis for the OH/O hydrogen bond, showing that the CH/π interaction between Phe6 and Lys123 is essential for PYP. The light-induced structural change of PYP is triggered by the breakage of the hydrophobic packing of Glu46. We showed that the CH/O interaction between carbonyl oxygen of the carboxylic acid of Glu46 and Cα of Gly29 stabilizes this hydrophobic packing. In addition, CH/π interactions between phenolic ring of the chromophore and nearby phenylalanine are essential for the stability and photocycle of PYP. These findings demonstrate that the weak interaction such as CH/O and CH/π interactions as well as the strong hydrogen bond should be taken into consideration to understand the structure and function of the proteins.
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