2023 Fiscal Year Final Research Report
Exploration of the determinants for making different functions between positive and negative phototaxis receptor sensory rhodopsins from the same species based on their function conversion experiments
Project/Area Number |
21K06091
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 43030:Functional biochemistry-related
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Research Institution | Matsuyama University |
Principal Investigator |
Tamogami Jun 松山大学, 薬学部, 准教授 (30580089)
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Co-Investigator(Kenkyū-buntansha) |
菊川 峰志 北海道大学, 先端生命科学研究院, 准教授 (20281842)
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Project Period (FY) |
2021-04-01 – 2024-03-31
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Keywords | 微生物型ロドプシン / センサリーロドプシン / レチナール / 光受容タンパク質 / 走光性 / シグナル伝達 / 分子間相互作用 / フォトサイクル |
Outline of Final Research Achievements |
The final goal of this study is to clarify the determinants for performing different functions between two kinds of sensor-type microbial rhodopsins, sensory rhodopsin I (SRI) and II (SRII) in haloarchaea, which are associated with opposite phototactic behaviors. In this study, we carried out photochemical characterizations and mutational analysis for their function conversion in highly stable SRI and SRII from Haloarcula vallismortis (HvSRI and HvSRII). Site-directed mutagenesis experiments in amino-acid residues located in the retinal binding site revealed that N83 in HvSRII is one of the responsible residues for making the difference between two SRs because the replacement of the residue with Leu, which is the corresponding residue in HvSRI, most significantly changed its spectroscopic properties (absorption maximum wavelength and photocycle), resulting in that these features got closer to those of HvSRI.
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Free Research Field |
生物物理化学
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Academic Significance and Societal Importance of the Research Achievements |
本研究より、高度好塩菌が生存に優位な光環境を求めて移動するために用いている2つのロドプシン型光受容体の性質の違いを生んでいるアミノ酸残基の1つを同定することができた。残念ながら本研究の最終目標である走光性機能の転換をもたらすアミノ酸残基の特定には至らなかったが、その候補残基の1つを見出すことができたと考える。また、微生物由来のロドプシンは、ヒトなどの高等生物のもつロドプシンをはじめとするGタンパク質共役型受容体とは基本的には異なるものではあるが、活性化時の構造変化等では共通点も指摘されており、この研究で得られた知見は、異種タンパク質間でのシグナル伝達機構の一般的理解にも貢献するものと考える。
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