クリプトクロムとフォトリアーゼにおけるフラビン共因子の超高速ダイナミクスとアニオン活性状態
Ya-Ting Kao1, Chuang Tan, Sang-Hun Song
1Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
Journal of the American Chemical Society
|May 27, 2008
まとめ
フラヴィンアデニンジヌクレオチド (FAD) のリドックス状態は,フォトリアーズとクリプトクロームで,アニオン型が機能の鍵であることを明らかにします. これらの状態は,DNA修復と青い光の光受容に不可欠な電子の転送を促進します.
科学分野:
- バイオケミストリー バイオケミストリー
- フォトケミストリー フォトケミストリー
- 分子生物学は分子生物学である.
背景:
- フォトリアーゼと暗号染色体は,DNA修復と光感知に関与するフラボタンパク質です.
- フラビン共因子には,その機能に不可欠な様々な酸化還元状態があります.
- フラヴィンダイナミクスを理解することは,光解離酵素と暗号染色体のメカニズムを解明する鍵です.
研究 の 目的:
- フォトリアーゼと昆虫の1型暗号染色体における4つのフラビン共因子リドックス状態の動態を体系的に研究する.
- これらのタンパク質における異なるフラビンリドックス状態の機能的関連性を決定する.
- その生物学的活動の基礎となる電子伝送メカニズムを解明する.
主な方法:
- 5秒間の時間解像度スペクトロスコピー.
- フラビン共因子ダイナミクスの体系的な研究.
- タンパク質内電子伝送経路の分析.
主要な成果:
- 酸化されたFADと中性FADHの状態は超高速光還元を示し,それらは主要な機能的状態ではないことを示唆しています.
- アニオンのFAD (((*-) とFADH (((-) 状態は寿命が長く,効率的な電子転送を容易にする.
- フォトリアーゼにおける刺激されたFADH(-)*は,DNA修復に最適なナノ秒の寿命を持っています.
- 暗号染色体における興奮FADは,タンパク質の動きによって調節される複雑なピコ秒の非活性化ダイナミクスを示している.
結論:
- アニオン性フラビン・レドックス状態は,フォトリアーゼとクリプトクロームの機能的役割にとって極めて重要です.
- アニオン性フラビンを含む普遍的な電子伝達機構は,DNA修復と青光光受容の両方の初期段階の基礎となっている可能性が高い.
- タンパク質のダイナミクスは,暗号染色体の機能を調節する役割を果たします.
さらに関連する動画
10:02Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
Published on: February 18, 2014
09:32Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development
Published on: June 15, 2017
関連する概念動画
Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Photosystem I
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
The Antenna Complex
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
ATP Synthase: Mechanism
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...
