Structure and energy transfer pathways of the Dunaliella Salina photosystem I supercomplex
Structure and energy transfer pathways of the Dunaliella Salina photosystem I supercomplex
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DOI：
10.1016/j.bbabio.2020.148253
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发表时间：
2020-10-01
影响因子：
4.3
通讯作者：
Nelson, Nathan
中科院分区：
文献类型：
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作者：
Caspy, Ido;Malavath, Tirupathi;Nelson, Nathan
30多亿年前，蓝藻进化出了含氧光合作用。从蓝细菌到植物等各种生物体中分离出的复合物获得的高分辨率结构中，光系统I（PSI）的复杂性增加变得明显。这些复合体都是进化上联系在一起的。在这篇论文中，研究人员发现了PSI在单一生物体中的复杂性增加，表现为两种不同的PSI成分共存。大型杜氏藻PSI含有八个额外的亚基，六个在PSI核心和两个捕光复合体。在PsaL和PsaO中确定了两个额外的叶绿素a分子，它们与状态II转换中的有效激发能量转移有关。这些新发现的叶绿素之间的短距离对应于快速的激发转移率先前报道在状态II过渡。表观PSI构象可能是应对高盐度的一种机制。
Oxygenic photosynthesis evolved more than 3 billion years ago in cyanobacteria. The increased complexity of photosystem I (PSI) became apparent from the high-resolution structures that were obtained for the complexes that were isolated from various organisms, ranging from cyanobacteria to plants. These complexes are all evolutionarily linked. In this paper, the researchers have uncovered the increased complexity of PSI in a single organism demonstrated by the coexistance of two distinct PSI compositions. The Large Dunaliella PSI contains eight additional subunits, six in PSI core and two light harvesting complexes. Two additional chlorophyll a molecules pertinent for efficient excitation energy transfer in state II transition were identified in PsaL and PsaO. Short distances between these newly identified chlorophylls correspond with fast excitation transfer rates previously reported during state II transition. The apparent PSI conformations could be a coping mechanism for the high salinity.