FUNCTION OF HELIOBACTERIA- AND GREEN SULFUR BACTERIA-TYPE REACTION CENTERS

日光细菌和绿硫细菌型反应中心的功能

基本信息

批准号：
10044218
负责人：
SAKURAI Hidehiro
金额：
$ 4.93万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In the reaction center complex (PS-C) from the green sulfur bacterium Chlorobium tepidum, A_0 and three Fe-S clusters function on the accepter side of the electron transfer chain and two molecules of cyt c-551 on the donor side. From multiple-flash-induced spectroscopy, we could not find any possibilities of functioning of quinone in the main electron transfer chain. On the donor side, the reduction rate of P840^+ after the first flash differed from that after the second flash, which was adequately explained by a functionally equivalent two cyt c-551 model. From the difference spectra of PS-C after the 1^<st>, 2^<nd> and the 3^<rd> flash, functioning of three Fe-S clusters was confirmed, corroborating the non-involvement of quinines on the acceptor side in the electron transfer chain, From the rereduction rates of P840^+, the rates of charge recombination between P840^+ and three Fe-S clusters and those of the leak of electron to the reaction mdeium were estimated. Analyses of the results indicate that the E_0 value of the most exposed Fe-S cluster is not the highest among the three. Four ferredoxins (Fd) were purified from C.tepidum. All of these Fd supported very high rate of NADP^+ photoreduction in the presence of PS-C from C.repidum and FNR from spinach, although their affinities differ each other.RC (PS-H) from Heliobacillus mobilis was solubilized with a detergent, and partially purified by sucrosedensity centrifugation, and by chromatography. The PS-H preparation contained several polypeptides, showed a low Fd-reducing activity, and was sensitive to oxygen. Two Fd were purified from the bacterium. One of them had high affinity with PS-C and the other low affinity.

在绿硫细菌tepidum的反应中心络合物（PS-C）中，在电子转移链的ACCEPTER侧的A_0和三个Fe-S簇的功能以及供体侧的Cyt C-551的两个分子。从多闪存诱导的光谱法中，我们找不到在主电子传输链中喹酮功能的任何可能性。在供体侧，第一个闪光灯之后的p840^+的降低速率与第二闪光后的降低率不同，这是通过功能等效的两个Cyt C-551模型充分解释的。从1^<st>，2^<nd>和3^<rd>闪光下的差异谱显示，确认了三个Fe-s簇的功能，证实了Quinines在电子转移链中的受体侧对Quinines在电子转移链中的不参与，从p840^+的电荷速率和p840^+之间的频率和p840^+的频率之间的反应速率和p840^+的三个反应速率，估计mdeium。对结果的分析表明，最暴露的Fe-S群集的E_0值不是三个中的最高值。从C.tepidum纯化了四个铁蛋白（FD）。所有这些FD在存在来自菠菜的c.repidum和fnr的PS-C存在下支持NADP^+光递增的速率非常高，尽管它们的亲和力彼此不同。来自Heliobacillus mobilis的RC（PS-H）用洗涤剂溶解，并用消洁剂溶解，并通过超密度的性强度分离式的离心型和crymoptication和Chromatography纯化。 PS-H制剂含有几种多肽，显示出低FD的活性，对氧气敏感。从细菌中纯化了两个FD。其中一个与PS-C和另一个低亲和力具有很高的亲和力。