Photosynthetic O2 formation tracked by time-resolved X-ray experiments

被引：375

作者：

Haumann, M ^{[1
]}

Liebisch, P ^{[1
]}

Müller, C ^{[1
]}

Barra, M ^{[1
]}

Grabolle, M ^{[1
]}

Dau, H ^{[1
]}

机构：

[1] Free Univ Berlin, FB Phys, D-14195 Berlin, Germany

来源：

SCIENCE | 2005年 / 310卷 / 5750期

关键词：

D O I：

10.1126/science.1117551

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Plants and cyanobacteria produce atmospheric dioxygen from water, powered by sunlight and catalyzed by a manganese complex in photosystem II. A classic S-cycle model for oxygen evolution involves five states, but only four have been identified. The missing S-4 state is particularly important because it is directly involved in dioxygen formation. Now progress comes from an x-ray technique that can monitor redox and structural changes in metal centers in real time with 10-microsecond resolution. We show that in the O-2-formation step, an intermediate is formed-the enigmatic S-4 state. Its creation is identified with a deprotonation process rather than the expected electron-transfer mechanism. Subsequent electron transfer would give an additional S-4' state, thus extending the fundamental S-state cycle of dioxygen formation.

引用

页码：1019 / 1021

页数：3

共 30 条

[21] Structure-based mechanism of photosynthetic water oxidation [J].