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Analysis of the Electron Transfer Pathway in the Green Sulfur Bacterial-Type Photochemical Reaction Center by a Conversion into the Pseudo Heterodimeric Structure

通过转换为伪异二聚结构分析绿硫细菌型光化学反应中心的电子传递途径

基本信息

批准号：
17570131
负责人：
OH-OKA Hirozo
金额：
$ 2.24万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

We studied on the structural and functional relationship of the type 1 reaction center in green sulfur bacteria and heliobacteria in order to understand profoundly the principle for the molecular construction of photosystem I reaction center in higher plants and cyanobacteria. The research progress in these two years is summarized as follows. 1. Searching for the Secondary Electron Acceptor A_1 (Quinone): The ESR signal derived from reduced quinone was successfully detected in the reaction center core complex in Heliobacterium modesticaldum. At present, we are now trying to identify its chemical species with HPLC and mass spectroscopic analyses. Meanwhile, we tried to obtain a mutant deleted of menG which encode a SAM-dependent methyl transferase in the quinone biosynthetic pathway. The back reaction of the oxidized P800^+ in the mutant had been expected to show some kind of different kinetics after a flash excitation. But we failed to obtain it. 2: Analyses of Sulfur Oxidation Pathway: Green sulfur bacteria use reduced sulfur compounds as an electron source. However, information concerning the linkage between sulfur oxidation and photosynthetic electron transfer pathways has long been scarce. Three mutants, that is, ΔcycA (a deletion mutant of CycA, cytochrome c-554), ΔsoxB (the SoxB-deleted one, which is one of subunits forming a multi-enzyme system involved in S_2O_3^<2-> oxidation) and a double mutant of ΔcycAΔsoxB, were constructed and we studied on the relationship between sulfur oxidation and photosynthetic electron transfer pathways. Although CycA surely serves as a terminal electron acceptor in the S_2O_3^<2-> oxidation pathway, another component should be involved in it as a probable bypath. Furthermore, each electron liberated from the S^<2-> and S_2O_3^<2-> oxidations, respectively, would be transferred to the P840 reaction center by a discrete electron transfer pathway.

为了更深入地了解高等植物和蓝藻光系统I反应中心的分子构建原理，我们对绿色硫杆菌和螺旋藻中的第一类反应中心的结构和功能关系进行了研究。这两年的研究进展总结如下。1.寻找次级电子受体A_1(对苯二酮)：在致病螺杆菌的反应中心核心复合体中成功检测到还原对苯二酚产生的ESR信号。目前，我们正在尝试用高效液相色谱和质谱分析来鉴定它的化学物种。同时，我们试图获得一个缺失的Meng突变体，该突变体编码苯醌生物合成途径中依赖于SAM的甲基转移酶。突变体中氧化的P800^+在闪光激发后的返回反应可能表现出某种不同的动力学。但我们没能拿到。2硫氧化途径分析：绿色硫磺细菌以还原硫化物为电子源。然而，关于硫氧化和光合作用电子传递途径之间的联系的信息一直很少。构建了3个突变体，即Δcyca(细胞色素c-554的缺失突变体)、ΔsoxB(SoxB缺失的突变体，它是参与S_2O_3氧化的多酶系统的亚基之一)和ΔcycaΔsoxB的双突变体，并研究了硫氧化与光合电子传递途径的关系。虽然Cyca在S氧化途径中肯定是一个末端电子受体，但另一个组分可能作为旁路参与其中。此外，从S^&lt；2-&gt；和S_2O_3^&lt；2-&gt；氧化反应中释放出来的每个电子都将通过离散的电子转移途径转移到P840反应中心。

项目成果

期刊论文数量（25）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Determination of stereochemistry of bacteriochlorophyll-g_F and 8^1- hvdroxy-chlorophyll-a_F from Heliobacterium modesticaldum.

微生物叶绿素-g_F 和 8^1-羟基叶绿素-a_F 立体化学的测定。

DOI：
发表时间：
2005
期刊：
Photochem. Photobiol. 81
影响因子：
0
作者：
Naoya;Shibayama;K.Wada;R.Miyamoto;Y.Tsukatani;J.Enkh-Amgalan;K.Wada;R.Miyamoto;Y.Tsukatani;K.Wada;Y.Tsukatani;J.Harada;J.Harada;T.Mizoguchi
通讯作者：
T.Mizoguchi

Different sensitivities to oxygen between two strains of the photosynthetic green sulfur bacterium Chlorobium vibrioforme NCIB 8327 with bacteriochlorophyll c and d

DOI：
10.1007/s11120-005-5669-8
发表时间：
2005-11-01
期刊：
PHOTOSYNTHESIS RESEARCH
影响因子：
3.7
作者：
Harada, J;Saga, Y;Tamiaki, H
通讯作者：
Tamiaki, H

Soluble cytochrome c-554, CycA, is not essential for photosynthetic electron transfer in Chlorobium tepidum

可溶性细胞色素 c-554 (CycA) 对于温绿绿藻的光合电子转移不是必需的

DOI：
发表时间：
2006
期刊：
FEBS Letters ARTICLE IN PRESS
影响因子：
0
作者：
Oda I;Hirata K;Watanabe S;Shibata Y;Kajino T;Fukushima Y;Iwai S;Itoh S;Yusuke Tsukatani
通讯作者：
Yusuke Tsukatani

Crystal structures of CbiL, a methyltransferase involved in anaerobic vitamin B_<12> biosynthesis, and CbiL in complex with S-adenosylhomocysteine. Implications for the reaction mechanism.

CbiL(一种参与厌氧维生素B_12生物合成的甲基转移酶)以及与S-腺苷高半胱氨酸复合物的CbiL的晶体结构。