ANTENNA ORGANIZATION AND EVIDENCE FOR THE FUNCTION OF A NEW ANTENNA PIGMENT SPECIES IN THE GREEN PHOTOSYNTHETIC BACTERIUM CHLOROFLEXUS-AURANTIACUS
ANTENNA ORGANIZATION AND EVIDENCE FOR THE FUNCTION OF A NEW ANTENNA PIGMENT SPECIES IN THE GREEN PHOTOSYNTHETIC BACTERIUM CHLOROFLEXUS-AURANTIACUS
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DOI：
10.1016/0005-2728(82)90011-1
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
FULLER, RC
中科院分区：
文献类型：
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作者：
BETTI, JA;BLANKENSHIP, RE;FULLER, RC
采用吸收光谱法（77度）研究了绿色光合细菌C. aurantiacus的全细胞和离体叶绿体（天线复合体）。K和室温)，荧光光谱，圆二色性（CD），线性二色性和ESR光谱。叶绿体吸收光谱的最大值为450 nm（类胡萝卜素和细菌叶绿素（BChl） a Soret）， 742 nm （BChl c）和792 nm (BChl a)，强度比为20:25。当激发进入742和450 nm吸收波段时，荧光发射光谱分别在748和802 nm处出现峰值。整个细胞具有与叶绿体相同的荧光峰，并增加了在867 nm处观察到的主峰。分离的叶绿体的CD谱在739nm处有一个不对称的导数形CD，表明激子相互作用至少在二聚体的水平上。定向叶绿体的线性二色性在742 nm平行于叶绿体长轴的偏光处表现出优先吸收。这意味着过渡偶极子的取向也或多或少平行于叶绿体的长轴。用铁氰化物处理后，在G 2.002处出现2.3 G宽ESR谱。当吸收归一化到742 nm时，在不同光照条件下生长的全细胞表现出不同的荧光行为。与强光条件下生长的细胞相比，弱光条件下生长的细胞在748 nm处的荧光强度更高，在802 nm处的荧光强度更低。叶绿体中的BChl c高度组织化，并将能量从BChl c （742 nm）传递到底板BChl B792 （BChl a）的连接器，可能位于靠近细胞质膜的叶绿体底板上。
Whole cells and isolated chlorosomes (antenna complex) of the green photosynthetic bacterium C. aurantiacus were studied by absorption spectroscopy (77.degree. K and room temperature), fluorescence spectroscopy, circular dichroism (CD), linear dichroism and ESR spectroscopy. The chlorosome absorption spectrum has maxima at 450 (contributed by carotenoids and bacteriochlorophyll (BChl) a Soret), 742 (BChl c) and 792 nm (BChl a) with intensity ratios of 20:25. The fluorescence emission spectrum has peaks at 748 and 802 nm when excitation is into either the 742 or 450 nm absorption bands, respectively. Whole cells have fluorescence peaks identical to those in chlorosomes with the addition of a major peak observed at 867 nm. The CD spectrum of isolated chlorosomes has an asymmetric-derivative-shaped CD centered at 739 nm suggestive of exciton interaction at least on the level of dimers. Linear dichroism of oriented chlorosomes shows preferential absorption at 742 nm of light polarized parallel to the long axis of the chlorosome. This implies that the transition dipoles are also oriented more or less parallel to the long axis of the chlorosome. Treatment with ferricyanide results in the appearance of a 2.3 G wide ESR spectrum at g 2.002. Whole cells grown under different light conditions exhibit different fluorescence behavior when absorption is normalized at 742 nm. Cells grown under low light conditions have higher fluorescence intensity at 748 nm and lower intensity at 802 nm than cells grown under high light conditions. The BChl c in chlorosomes is highly organized and transfers energy from BChl c (742 nm) to a connector of baseplate BChl B792 (BChl a) presumably located in the chlorosome baseplate adjacent to the cytoplasmic membrane.