Development and dynamics of the photosynthetic apparatus in purple phototrophic bacteria
Development and dynamics of the photosynthetic apparatus in purple phototrophic bacteria
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DOI：
10.1016/j.bbabio.2015.10.014
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发表时间：
2016-03-01
影响因子：
4.3
通讯作者：
Niederman, Robert A.
中科院分区：
文献类型：
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作者：
Niederman, Robert A.
球形红细菌为研究细菌光合膜的组装和动力学提供了一个有用的模型系统。对于新生的发展中的膜，蛋白质组学分析表明，在一般的膜组装因子的2倍富集，相比，色素。当将质子载体羰基氰化物间氯苯腙（CCCP）添加到ICM诱导培养物中时，观察到SecA易位ATP酶、前蛋白易位酶SecY、SecD和SecF插入组分以及在组装过程早期起作用的伴侣蛋白DnaJ和DnaK的光谱计数与对照相比类似于2倍的升高。有人建议，这些因素积累与他们的新生多肽，作为推定的组装中间体在功能上被逮捕的状态。由于在集胞藻PCC 6803中，已经在涉及高光HiID蛋白的Chl递送和新生多肽的SecY/YidC需要的共翻译插入之间建立了联系，这种BChl生物合成与新生Rba的插入和折叠之间的联系。sphaeroides BChl结合蛋白也可能发生。原子力显微镜成像研究的反应中心（RC）光捕获1（LH1）复合物的形成提出了一个合作的组装机制，其中，以下的RC模板和初始LH1单元之间的关联，除了连续的LH1单元的RC驱动组装过程完成。通过荧光诱导/弛豫动力学评估了随着发育中的膜变得充满LH 2-环，膜动力学的改变，其显示RC电子转移速率的减慢，认为这主要反映了供体侧电子转移的改变。正如当前结构模型所表明的那样，这归因于RC和细胞色素bc（1）复合物之间细胞色素c（2）中电子流动的距离增加。本文是由Conrad Mullineaux教授编辑的题为细菌生物能量系统的组织和动力学的特刊的一部分。(C)2015年由Elsevier B.V.出版
The purple bacterium Rhodobacter sphaeroides provides a useful model system for studies of the assembly and dynamics of bacterial photosynthetic membranes. For the nascent developing membrane, proteomic analyses showed an similar to 2-fold enrichment in general membrane assembly factors, compared to chromatophores. When the protonophore carbonyl-cyanide m-chlorophenyl-hydrazone (CCCP) was added to an ICM inducing culture, an similar to 2-fold elevation in spectral counts vs. the control was seen for the SecA translocation ATPase, the preprotein translocase SecY, SecD and SecF insertion components, and chaperonins DnaJ and DnaK, which act early in the assembly process. It is suggested that these factors accumulated with their nascent polypeptides, as putative assembly intermediates in a functionally arrested state. Since in Synechocystis PCC 6803, a link has been established between Chl delivery involving the high-light HiID protein and the SecY/YidC-requiring cotranslational insertion of nascent polypeptides, such a connection between BChl biosynthesis and insertion and folding of nascent Rba. sphaeroides BChl binding proteins is likely to also occur. AFM imaging studies of the formation of the reaction center (RC) light harvesting 1 (LH1) complex suggested a cooperative assembly mechanism in which, following the association between the RC template and the initial LH1 unit, addition of successive LH1 units to the RC drives the assembly process to completion. Alterations in membrane dynamics as the developing membrane becomes filled with LH2-rings were assessed by fluorescence induction/relaxation kinetics, which showed a slowing in RC electron transfer rate thought to mainly reflect alterations in donor side electron transfer. This was attributed to an increased distance for electron flow in cytochrome c(2) between the RC and cytochrome bc(1) complexes, as suggested in the current structural models. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux. (C) 2015 Published by Elsevier B.V.