红藻藻胆体内部蛋白间的能量传递研究 Ⅰ.人工合成R-PE/R-PC/APC复合物内的能量传递

研究了人工合成的藻胆体模拟复合物的时间分辨荧光光谱,并运用多指数拟合的方法对数据进行了详细的处理和分析,结果表明能量在Ｒ－ＰＥ和Ｒ－ＰＣ之间的传递时间与能量从Ｒ－ＰＣ传递到ＡＰＣ的时间几乎相等（５０ｐｓ）;除此之外,Ｒ－ＰＥ到ＡＰＣ还有两种能量传递的通道,能量在这两个通道的传递时间分别为１１０ｐｓ和４００ｐｓ．即：蛋白之间的能量传递通道是并行的．     

基于藻胆体纯化鉴定的生物综合实验设计及其优势

藻胆体是一些光合藻类吸收传递光能的色素蛋白复合体,设计面向生命科学高年级本科生的综合实验,包括了藻胆体的分离、纯化、组成鉴定及性质分析,详细分析了该综合实验的特点、具有的优势以及存在的问题。     

ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium Anabaena sp.PCC7120

Pbycobilisomes(PBS) are able to transfer absorbed energy to photosystem I and Ⅱ,and the distribution of light energy between two photosystems is regulated by state transitions.In this study we show that energy transfer from PBS to photosystem I(PSI) requires ApcD.Cells were unable to perform state transitions in the absence of ApcD.The apcD mutant grows more slowly in light mainly absorbed by PBS,indicating that ApcD-dependent energy transfer to PSI is required for optimal growth under this condition.The apcD mutant showed normal blue-light induced quenching,suggesting that ApcD is not required for this process and state transitions are independent of blue-light induced quenching.Under nitrogen fixing condition,the growth rates of the wild type and the mutant were the same,indicating that energy transfer from PBS to PSI in heterocysts was not required for nitrogen fixation.     

海生红藻多管藻中的2种R-藻红蛋白

以新鲜的海生红藻多管藻(Polysiphonia urceolata Grev)为材料,通过DEAE-52离子交换层析,Sephadex G-150和Sephacryl S-300凝胶过滤层析纯化制备了2种R-藻红蛋白(R-phycoerythrin,R-PE)PE272-1和PE377-2.两者有非常相似的光谱特性,...     

ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium <Emphasis Type="Italic">Anabaena</Emphasis> sp. PCC7120

Pbycobilisomes （PBS） are able to transfer absorbed energy to photosystem Ⅰ and Ⅱ, and the distribution of light energy between two photosystems is regulated by state transitions. In this study we show that energy transfer from PBS to photosystem Ⅰ （PSI） requires ApcD. Cells were unable to perform state transitions in the absence of ApcD. The apcD mutant grows more slowly in light mainly absorbed by PBS, indicating that ApcD-dependent energy transfer to PSI is required for optimal growth under this condition. The apcD mutant showed normal blue-light induced quenching, suggesting that ApcD is not required for this process and state transitions are independent of blue-light induced quenching. Under nitrogen fixing condition, the growth rates of the wild type and the mutant were the same, indicating that energy transfer from PBS to PSI in heterocysts was not required for nitrogen fixation.     

New mechanism revealed for light-state transition in cyanobacterium Arthrospira platensis according to 77-K fluorescence kinetics

The mechanisms of oxygen evolution and carbon fixation in oxygenic organisms depend on the equal distribution of excitation energy to photosystems Ⅰ and Ⅱ, which is regulated by a mechanism referred to as light-state transition. In this work, a novel mechanism, energy spillover from PS Ⅰ to PS Ⅱ referred to as "inverse spillover", was revealed besides "mobile phycobilisome (PBS)" and the "spillover" of energy from PS Ⅱ to PS Ⅰ in cyanobacteria. Under continuous illumination with blue light, time-dependent 77-K fluorescence spectra demonstrated heterogeneous kinetics for the PBS and photosystem components, indicating that inverse spillover and mobile PBS work successively to regulate the excitation to a balanced distribution in cyanobacterial cells under blue light. Inverse spillover and mobile PBS occur under both 100 and 300 μmol m-2 s-1 blue-light conditions but they are accelerated under the latter.     

红藻藻胆体内部蛋白间的能量传递研究 Ⅲ.人工合成复合物R-PC/APC内的能量传递

研究了人工合成的二元藻胆体模拟复合物（ＲＰＣ／ＡＰＣ）的时间分辨荧光光谱并运用多指数拟合的方法对数据进行了详细的处理和分析,研究结果证实了能量在ＲＰＣ和ＡＰＣ之间的传递时间与能量从ＲＰＥ传递到ＲＰＣ的时间几乎相等（５０ｐｓ）;除此之外,ＲＰＣ到ＡＰＣ没有其它能量传递的通道．结果为能量可以从ＲＰＥ直接传递到ＡＰＣ同时也可以经过ＲＰＣ传递到ＡＰＣ,ＲＰＣ作为能量传递的中间受体,在实际的体系中其作用是通过竞争的机制实现的．     

Changes in the transthylakoid proton gradient are caused by the movement of phycobilisomes in the cyanobacterium <Emphasis Type="Italic">Synechocystis</Emphasis> sp. strain PCC 6803

Phycobilisomes (PBSs) are the main accessory light-harvesting complexes in cyanobacteria and their movement between photosystems (PSs) affects cyclic and respiratory electron transport. However, it remains unclear whether the movement of PBSs between PSs also affects the transthylakoid proton gradient (ΔpH). We investigated the effect of PBS movement on ΔpH levels in a unicellular cyanobacterium Synechocystis sp. strain PCC 6803, using glycinebetaine to immobilize and couple PBSs to photosystem II (PSII) or photosystem I (PSI) by applying under far-red or green light, respectively. The immobilization of PBSs at PSII inhibited decreases in ΔpH, as reflected by the slow phase of millisecond-delayed light emission (ms-DLE) that occurs during the movement of PBSs from PSII to PSI. By contrast, the immobilization of PBSs at PSI inhibited the increase in ΔpH that occurs when PBSs move from PSI to PSII. Comparison of the changes in ΔpH and electron transport caused by the movement of PBSs between PSs indicated that the changes in ΔpH were most likely caused by respiratory electron transport. This will further improve our understanding of the physiological role of PBS movement in cyanobacteria.     

藻胆体稳定性的研究（Ⅴ）—pH对藻胆体稳定性的影响

不同ｐＨ对多变鱼腥藻（Ａｎａｂａｅｎａｖａｒｉａｂｉｌｉｓ）藻胆体荧光发射光谱，光能传递和解离的影响．在ｐＨ７磷酸缓冲溶液中，藻胆体处于稳定状态，不发生解离．在ｐＨ６，８，９，１０磷酸缓冲溶液中，藻胆体仍处于较稳定状态，没有解离．在ｐＨ５，５．５和１０．５磷酸缓冲溶液中，藻胆体发生弱解离．在ｐＨ４．５缓冲溶液中，藻胆体发生明显解离．在ｐＨ４和１１缓冲溶液中，藻胆体发生严重解离；藻红蓝蛋白，Ｃ－藻蓝蛋白和别藻蓝蛋白所捕获的光能已不能传递给末端发射体