A Supercomplex, of Approximately 720 kDa and Composed of Both Photosystem Reaction Centers, Dissipates Excess Energy by PSI in Green Macroalgae Under Salt Stress
A Supercomplex, of Approximately 720 kDa and Composed of Both Photosystem Reaction Centers, Dissipates Excess Energy by PSI in Green Macroalgae Under Salt Stress
复制标题
约 720 kDa 的超级复合物由两个光系统反应中心组成，在盐胁迫下通过 PSI 耗散绿色大型藻类中的多余能量
DOI：
10.1093/pcp/pcy201
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发表时间：
2019-01-01
影响因子：
4.9
通讯作者：
Wang, Guangce
中科院分区：
文献类型：
--
作者：
Gao, Shan;Chi, Zhen;Wang, Guangce
The thylakoid membranes of plants play a critical role in electron transfer and energy fixation, and are highly dynamic. So far, studies on the thylakoid membranes have mainly focused on microalgae and higher plants, yet very little information is available on the macroalgal thylakoids. Here, we studied the structure and organization of the thylakoid membranes in Ulva prolifera, a representative species of the green macroalgae. We found that U. prolifera had few but long loosely stacked membranes which lack the conventional grana found in higher plants. However, the thylakoid membrane complexes demonstrate lateral heterogeneity. Moreover, we found a supercomplex composed of PSII, light-harvesting complex II (LHCII) and PSI from U. prolifera under salt stress. The supercomplex is approximately 720 kDa, and includes the two important photoprotection proteins, the PSII S subunit (PsbS) and the light-harvesting complex stress-related protein (LhcSR), as well as xanthophyll cycle pigments (violaxanthin, antheraxanthin and zeaxanthin). Time-resolved fluorescence analysis suggested that, in the supercomplex, excitation energy could efficiently be transferred from PSII to PSI, even when PSII was inhibited, a function which disappeared when the supercomplex was incubated in mild detergent. We suggest that the supercomplex might be an important mechanism to dissipate excess energy by PSI in green macroalgae under salt stress.
