We demonstrated the existence of PSI-LHCI-LHCII-Lhcb4 supercomplexes and PSI-LHCI-PSII-LHCII megacomplexes in the stroma lamellae and grana margins of maize mesophyll chloroplasts; these complexes consist of different LHCII trimers and monomer antenna proteins per PSI photocentre. These complexes are formed in both low (LL) and high (HL) light growth conditions, but with different contents. We attempted to identify the components and structure of these complexes in maize chloroplasts isolated from the leaves of low and high light-grown plants after darkness and transition to far red (FR) light of high intensity. Exposition of plants from high and low light growth condition on FR light induces different rearrangements in the composition of super- and megacomplexes. During FR light exposure, in plants from LL, the PSI-LHCI-LHCII-Lhcb4 supercomplex dissociates into free LHCII-Lhcb4 and PSI-LHCI complexes, and these complexes associate with the PSII monomer. This process occurs differently in plants from HL. Exposition to FR light causes dissociation of both PSI-LHCI-LHCII-Lhcb4 supercomplexes and PSI-PSII megacomplexes. These results suggest a different function of super- and megacomplex organization than the classic state transitions model, which assumes that the movement of LHCII trimers in the thylakoid membraneis considered as a mechanism for balancing light absorption between the two photosystems in light stress. The behavior of the complexes described in this article does not seem to be well explained by this model, i.e., it does not seem likely that the primary purpose of these megacomplexes dynamics is to balance excitation pressure. Rather, as stated in this article, it seems to indicate a role of these complexes for PSI in excitation quenching and for PSII in turnover.

中文翻译：

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光对玉米叶肉叶绿体非贴壁类囊体结构域中 PSI 超复合物和巨复合物重排的影响

我们证明了 PSI-LHCI-LHCII-Lhcb4 超级复合物和 PSI-LHCI-PSII-LHCII 超级复合物存在于玉米叶肉叶绿体的基质层和谷粒边缘；这些复合物由不同的 LHCII 三聚体和每个 PSI 光中心的单体天线蛋白组成。这些复合物在低 (LL) 和高 (HL) 光生长条件下形成，但含量不同。我们试图在黑暗和过渡到高强度远红 (FR) 光后，从低光和高光生长植物的叶子中分离出玉米叶绿体，以确定这些复合物的成分和结构。在 FR 光下从高光和低光生长条件下暴露植物会导致超级复合物和超级复合物的组成发生不同的重排。在 FR 光照期间，在来自 LL 的植物中，PSI-LHCI-LHCII-Lhcb4 超复合物解离成游离的 LHCII-Lhcb4 和 PSI-LHCI 复合物，这些复合物与 PSII 单体结合。这个过程在来自 HL 的植物中发生的方式不同。暴露于 FR 光会导致 PSI-LHCI-LHCII-Lhcb4 超复合物和 PSI-PSII 超级复合物解离。这些结果表明超复合体和超复合体组织的功能与经典状态转换模型不同，经典状态转换模型假设类囊体膜中 LHCII 三聚体的运动被认为是在光应力下平衡两个光系统之间光吸收的机制。这篇文章中描述的复合体的行为似乎没有被这个模型很好地解释，即这些巨型复合体动力学的主要目的似乎不太可能是平衡激发压力。相当，