B850 PIGMENT-PROTEIN COMPLEX OF RHODOPSEUDOMONAS-SPHAEROIDES - EXTINCTION COEFFICIENTS, CIRCULAR-DICHROISM, AND THE REVERSIBLE BINDING OF BACTERIOCHLOROPHYLL
B850 PIGMENT-PROTEIN COMPLEX OF RHODOPSEUDOMONAS-SPHAEROIDES - EXTINCTION COEFFICIENTS, CIRCULAR-DICHROISM, AND THE REVERSIBLE BINDING OF BACTERIOCHLOROPHYLL
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DOI：
10.1073/pnas.78.9.5583
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
CLAYTON, BJ
中科院分区：
文献类型：
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作者：
CLAYTON, RK;CLAYTON, BJ
根据分离方法的不同，球藻的色素体产生两种状态中的一种，即天线复合体B850。方法利用十二烷基二甲胺氧化物产率B850，其吸收光谱与体内相似：在800和850 nm处，由于细菌叶绿素（Bchl）成分Bchl-800和Bchl-850的比值为A800/A850 = 0.65 .+-。0.05. 当用十二烷基硫酸盐分离B850时，Bchl-800被稀释或不存在。对这些材料和隔离天线复合体B875的Bchl测定得出了以下消光系数：。+-。SD，根据Bchl的摩尔浓度：对于B875，为。epsilon。875 = 126 .+-。8毫米-1厘米-1。对于正常（高bchl -800）状态的B850， .epsilon。850 = 132 .+-10 mM-1 cm-1。对于B850中Bchl的各个分量，。850的Bchl-850 = 184。13 mM-1 cm-1和。Bchl-800的8800 = 213 +-。28 mM-1 cm-1。根据这些系数，Bchl-850与Bchl-800的分子比为1.8 +-。B850在高bchl -800状态下为0.4。从B850的Bchl-800缺失开始，十二烷基二甲胺氧化物的加入恢复了800 nm的吸收带。850纳米波段向蓝色偏移，变窄并略有减弱，其相关的圆二色性变得更强烈20%。与十二烷基二甲胺氧化物一起添加游离Bchl可以加速Bchl-800的恢复，延缓Bchl-850的衰减。游离Bchl可以与B850配合物中Bchl-800的结合位点发生明显的可逆相互作用，硫酸十二烷基有利于解离，氧化十二烷基二甲胺促进结合。因此，天然叶绿素-蛋白质复合物的可逆解离现在已经得到证实。
Chromatophores of R. sphaeroides yield the antenna complex B850 in either of 2 states, depending on the method of isolation. Methods using dodecyldimethylamine oxide yield B850 with an absorption spectrum like that in vivo: the bands at 800 and 850 nm, due to the bacteriochlorophyll (Bchl) components Bchl-800 and Bchl-850, are in ratio A800/A850 = 0.65 .+-. 0.05. When B850 is isolated by methods using dodecyl sulfate, the Bchl-800 is attenuated or absent. Bchl assays of these materials and of the isolated antenna complex B875 yielded the following extinction coefficients, .+-. SD, on the basis of the molarity of Bchl: for B875, .epsilon.875 = 126 .+-. 8 mMA-1 cm-1. For B850 in the normal (high-Bchl-800) state, .epsilon.850 = 132 .+-. 10 mM-1 cm-1. For the individual components of Bchl in B850, .epsilon.850 of Bchl-850 = 184 .+-. 13 mM-1 cm-1 and .epsilon.8800 of Bchl-800 = 213 .+-. 28 mM-1 cm-1. With these coefficients the molecular ratio of Bchl-850 to Bchl-800 equals 1.8 .+-. 0.4 for B850 in the high-Bchl-800 state. Starting with B850 depleted of Bchl-800, the addition of dodecyldimethylamine oxide restored the 800-nm absorption band. The 850-nm band became shifted toward the blue, narrowed and slightly attenuated, and its associated circular dichroism became 20% more intense. Free Bchl added with dodecyldimethylamine oxide accelerated the restoration of Bchl-800 and retarded the attenuation of Bchl-850. Free Bchl can apparently interact reversibly with a binding site for Bchl-800 in B850 complex, with dodecyl sulfate favoring dissociation and dodecyldimethylamine oxide promoting association. Thus the reversible dissociation of a native chlorophyll-protein complex has now been demonstrated.