Horton Peter, Johnson Matthew P, Perez-Bueno Maria L, Kiss Anett Z, Ruban Alexander V
Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK.
FEBS J. 2008 Mar;275(6):1069-79. doi: 10.1111/j.1742-4658.2008.06263.x.
The efficiency of light harvesting in higher plant photosynthesis is regulated in response to external environmental conditions. Under conditions of excess light, the normally highly efficient light-harvesting system of photosystem II is switched into a state in which unwanted, potentially harmful, energy is dissipated as heat. This process, known as nonphotochemical quenching, occurs by the creation of energy quenchers following conformational change in the light-harvesting complexes, which is initiated by the build up of the thylakoid pH gradient and controlled by the xanthophyll cycle. In the present study, the evidence to support the notion that this regulatory mechanism is dependent upon the organization of the different antenna subunits in the stacked grana membranes is reviewed. We postulate that nonphotochemical quenching occurs within a structural locus comprising the PsbS subunit and components of the light-harvesting antenna, CP26, CP24, CP29 and LHCIIb (the major trimeric light-harvesting complex), formed in response to protonation and controlled by the xanthophyll cycle carotenoids.
高等植物光合作用中光捕获的效率会根据外部环境条件进行调节。在光照过剩的条件下，光系统II通常高效的光捕获系统会转变为一种状态，即多余的、潜在有害的能量以热量形式耗散。这个过程称为非光化学猝灭，它是通过光捕获复合物构象变化后产生能量猝灭剂而发生的，这种构象变化由类囊体pH梯度的积累引发，并受叶黄素循环控制。在本研究中，我们回顾了支持这种调节机制依赖于堆叠的基粒膜中不同天线亚基组织的证据。我们推测，非光化学猝灭发生在一个结构位点内，该位点由PsbS亚基以及光捕获天线CP26、CP24、CP29和LHCIIb（主要的三聚体光捕获复合物）的组分组成，这些组分是响应质子化而形成的，并受叶黄素循环类胡萝卜素控制。
