フォトシステムIにおける光化学的エネルギー変換の長波長限界
Eberhard Schlodder1, Friedhelm Lendzian, Jenny Meyer
1Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität Berlin , Strasse des 17. Juni 135, 10623 Berlin, Germany.
Journal of the American Chemical Society
|February 13, 2014
まとめ
フォトシステムI (PS I) は,長波長クロロフィルの吸収以外でも,800nmを超える遠赤色光を吸収して,光化学を駆動することができます. これは,電荷伝送状態の直接刺激によって発生し,PSIを拡張します.
科学分野:
- 光合成の研究研究である.
- バイオフィジックス 生物物理学
- 植物学は植物科学である.
背景:
- Photosystem I (PS I) は,光化学のために長波長クロロフィール (LWC) を使用して,最大750 nmの光を吸収します.
- PS Iにおける光吸収のスペクトル限界は,エネルギー変換効率を理解するために重要である.
研究 の 目的:
- 800 nmを超える遠赤色の光によって誘発されるPS Iにおける光化学的電荷分離のメカニズムを調査する.
- LWCが波長>800 nmでの電荷分離に責任があるかどうかを判断する.
- 遠赤色の光の吸収を司る光の吸収種の性質を特定する.
主な方法:
- 295Kから5Kまでの温度でThermosynechococcus elongatusとArthrospira platensisからPSIコア複合体のスペクトル解析 (吸収とEPR)
- 特定の波長 (754,785,808 nm) を用いたPSIの選択刺激.
- P700酸化および電荷分離中間物質のモニタリング.
主要な成果:
- PS Iにおける光化学的電荷分離は,研究された全温度範囲で,波長>800 nmの光によって誘導された.
- P700の酸化とP700 (((+•) FA/B (((-•) の形成は,754,785および808 nmの刺激時に観察されました.
- 観測された現象は,LWCの含有量とは無関係であり,これらの遠赤波長でLWCが主要な吸収体であることを排除しました.
結論:
- 波長>800 nmのPS Iでの電荷分離は,LWCによって媒介されません.
- この発見は,PSI反応センター内の電荷移転 (CT) 状態の直接刺激が原因であることを強く示唆しています.
- このメカニズムは,PS Iの機能的スペクトル範囲をLWC吸収を超えて拡張し,他の光活性システムに潜在的な影響を及ぼします.
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