藻蓝蛋白体 2 有效荧光截面的蓝细菌集胞藻 PCC6803 及其突变体。
Photosystem 2 effective fluorescence cross-section of cyanobacterium Synechocystis sp. PCC6803 and its mutants.
机构信息
Department of Biophysics, Biological Faculty of the M.V. Lomonosov Moscow State University, 119991 Moscow, Russia.
出版信息
J Photochem Photobiol B. 2011 Jul-Aug;104(1-2):285-91. doi: 10.1016/j.jphotobiol.2011.02.011. Epub 2011 Feb 21.
The effective fluorescence cross-section of photosystem 2 (PS2) was defined by measurements of chlorophyll a fluorescence induction curves for the wild type of the unicellular cyanobacterium Synechocystis sp. PCC6803, C-phycocyanin deficient mutant (CK), and mutant that totally lacks phycobilisomes (PAL). It was shown that mutations lead to a strong decrease of the PS2 effective fluorescence cross-section. For instance, the effective fluorescence cross-section of PS2 for wild type, CK and PAL mutants excited at λ(ex)=655 nm were found to be 896, 220 and 83 Å(2) respectively. Here we present an estimation of energy transfer efficiency from phycobilisomes to the pigment-protein complexes of PS2. It was shown that the PS2 fluorescence enhancement coefficient reaches a maximum value of 10.7 due to the energy migration from phycobilisomes. The rate constant of energy migration was found to be equal to 1.04 × 10(10) s(-1).
通过测量单细胞蓝藻集胞藻 PCC6803 的野生型、藻红蛋白缺陷突变体（CK）和完全缺乏藻胆体的突变体（PAL）的叶绿素 a 荧光诱导曲线，定义了光系统 2（PS2）的有效荧光截面。结果表明，突变导致 PS2 的有效荧光截面强烈降低。例如，在 λ(ex)=655nm 激发下，野生型、CK 和 PAL 突变体的 PS2 有效荧光截面分别为 896、220 和 83Å(2)。在这里，我们提出了一种估计从藻胆体到 PS2 的色素蛋白复合物的能量转移效率的方法。结果表明，由于能量从藻胆体迁移，PS2 荧光增强系数达到最大值 10.7。能量迁移的速率常数被发现等于 1.04×10(10)s(-1)。
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