The Light-Harvesting Chlorophyll a/b Binding Proteins Lhcb1 and Lhcb2 Play Complementary Roles during State Transitions in Arabidopsis
The Light-Harvesting Chlorophyll a/b Binding Proteins Lhcb1 and Lhcb2 Play Complementary Roles during State Transitions in Arabidopsis
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DOI：
10.1105/tpc.114.127373
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发表时间：
2014-09-01
期刊：
影响因子：
11.6
通讯作者：
Jansson, Stefan
中科院分区：
文献类型：
--
作者：
Pietrzykowska, Malgorzata;Suorsa, Marjaana;Jansson, Stefan
植物的光合捕光受磷酸化驱动的状态转换的调节：主要三聚体捕光复合物II（LHCII）的功能重新分配，以平衡光系统I和光系统II的相对激发。状态转换由STN 7激酶和PPH 1/TAP 38磷酸酶的可逆LHCII磷酸化驱动。LHCII三聚体由Lhcb 1、Lhcb 2和Lhcb 3蛋白以各种三聚体构型组成。在这里，我们表明，尽管他们几乎相同的氨基酸组成，Lhcb 1和Lhcb 2的功能作用是不同的，但互补的。拟南芥植物缺乏Lhcb 2含有类似于野生型植物，其中Lhcb 2已被Lhcb 1取代的类囊体蛋白复合物。然而，这些不进行状态转换，因此Lhcb 2的磷酸化似乎是一个关键步骤。相比之下，缺乏Lhcb 1的植物有一个更深刻的天线重塑由于LHCII三聚体的量减少影响类囊体膜结构，更间接地，状态转换。虽然在绿色藻类中也发现了状态转换，但现存种子植物捕光天线的详细结构现在可以追溯到brandite和种子植物谱系分化之后的一段时间，但在被子植物和裸子植物谱系分裂之前，超过3亿年前。
Photosynthetic light harvesting in plants is regulated by phosphorylation-driven state transitions: functional redistributions of the major trimeric light-harvesting complex II (LHCII) to balance the relative excitation of photosystem I and photosystem II. State transitions are driven by reversible LHCII phosphorylation by the STN7 kinase and PPH1/TAP38 phosphatase. LHCII trimers are composed of Lhcb1, Lhcb2, and Lhcb3 proteins in various trimeric configurations. Here, we show that despite their nearly identical amino acid composition, the functional roles of Lhcb1 and Lhcb2 are different but complementary. Arabidopsis thaliana plants lacking only Lhcb2 contain thylakoid protein complexes similar to wild-type plants, where Lhcb2 has been replaced by Lhcb1. However, these do not perform state transitions, so phosphorylation of Lhcb2 seems to be a critical step. In contrast, plants lacking Lhcb1 had a more profound antenna remodeling due to a decrease in the amount of LHCII trimers influencing thylakoid membrane structure and, more indirectly, state transitions. Although state transitions are also found in green algae, the detailed architecture of the extant seed plant light-harvesting antenna can now be dated back to a time after the divergence of the bryophyte and spermatophyte lineages, but before the split of the angiosperm and gymnosperm lineages more than 300 million years ago.