3.8 A解像度でSynechococcus elongatusからの光システムIIの結晶構造
1Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Technische Universität Berlin, Germany.
Nature
|February 24, 2001
まとめ
研究者は,光システムIIのX線構造を決定し,そのタンパク質サブユニットとコファクターの空間的組織を明らかにしました. この画期的な発見は,光合成における水の酸化に不可欠なマンガンのクラスターに関する新しい洞察を提供します.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 光合成研究 研究 光合成研究
背景:
- 光学系Iと光学系IIによって推進される酸素光合成は,地球の主要なエネルギー変換プロセスです.
- 光システムII (PSII) は,水を酸化し,電子,陽子を供給し,酸素を放出するために不可欠です.
- 以前の構造データには解像度や水酸化活動が欠けていた.
研究 の 目的:
- 活性光システムIIの高解像度X線構造を決定する.
- PSII内のタンパク質サブユニットとコファクターの空間的組織を解明する.
- 水酸化に関与するマンガネスクラスターに関する詳細な情報を提供するため.
主な方法:
- 完全活性光系IIの結晶のX線結晶学.
- 完ぺきなPSIIの電子顕微鏡データの分析.
- PSII 断片の電子結晶学.
主要な成果:
- 活性光系IIのX線構造が決定されました.
- タンパク質サブユニットとコファクターの空間的組織が明らかになった.
- マンガンのクラスタの正確な位置,方向,および詳細が定義されました.
結論:
- この研究は,活性光システムIIの詳細な構造モデルを提供します.
- マンガンのクラスターの構造を理解することは,水の酸化機構の洞察を提供します.
- この研究は,光合成研究とバイオエネルギー学の分野を前進させています.
関連する概念動画
01:22Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
01:27Photosystem 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...
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:29The 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...
01:32Photosystems
Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in the membrane of tiny sac-like structures called thylakoids placed inside the chloroplast.
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...