Evolution of the acceptor side of photosystem I: ferredoxin, flavodoxin, and ferredoxin-NADP+ oxidoreductase
Evolution of the acceptor side of photosystem I: ferredoxin, flavodoxin, and ferredoxin-NADP+ oxidoreductase
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DOI：
10.1007/s11120-017-0338-2
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发表时间：
2017-02
影响因子：
3.7
通讯作者：
J. P. Pierella Karlusich;N. Carrillo
中科院分区：
文献类型：
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作者：
J. P. Pierella Karlusich;N. Carrillo
27亿年前原始蓝藻的产氧光合作用的发展导致光合电子传递的组成和组织发生重大变化，以科普富氧大气的挑战。我们在此审查，以下的开创性贡献报告Jaganathan等人。（Functional genomics and evolution of photosynthesis systems，vol 33，advances in photosynthesis and respiration，Springer，多尔德雷赫特，2012），这些变化如何影响光系统I（PSI）受体侧的载体和酶：电子穿梭铁氧还蛋白（Fd）、其同功能对应物黄素氧还蛋白（Fld）、它们的氧化还原配偶体铁氧还蛋白-NADP+还原酶（FNR）以及主要PSI受体Fx和FA/FB。保护这些蛋白质的[4Fe-4S]中心免受氧化损伤是通过加强FA/FB多肽与含有Fx的反应中心核心之间的结合来实现的，从而削弱O2进入簇。PSI复合物中FA/F的固定化又导致了新的可溶性电子穿梭的募集。这一功能由氧不敏感的[2Fe-2S] Fd实现，其中簇的反应性硫化物原子被多肽骨架从溶剂中屏蔽，并且在一些藻类和蓝藻中由Fld实现，Fld采用黄素作为辅基并且耐受氧化剂和铁限制。FNR的紧密膜结合允许固态电子转移从Fd/Fld桥接的PSI。FNR催化机制的微调导致了巨大的增加周转率相比，FNR作用于异养途径，有利于Fd/Fld还原，而不是氧还原。
The development of oxygenic photosynthesis by primordial cyanobacteria ~2.7 billion years ago led to major changes in the components and organization of photosynthetic electron transport to cope with the challenges of an oxygen-enriched atmosphere. We review herein, following the seminal contributions as reported by Jaganathan et al. (Functional genomics and evolution of photosynthetic systems, vol 33, advances in photosynthesis and respiration, Springer, Dordrecht, 2012), how these changes affected carriers and enzymes at the acceptor side of photosystem I (PSI): the electron shuttle ferredoxin (Fd), its isofunctional counterpart flavodoxin (Fld), their redox partner ferredoxin-NADP+reductase (FNR), and the primary PSI acceptorsFxandFA/FB. Protection of the [4Fe–4S] centers of these proteins from oxidative damage was achieved by strengthening binding between theFA/FBpolypeptide and the reaction center core containingFx, therefore impairing O2access to the clusters. Immobilization ofFA/FBin the PSI complex led in turn to the recruitment of new soluble electron shuttles. This function was fulfilled by oxygen-insensitive [2Fe–2S] Fd, in which the reactive sulfide atoms of the cluster are shielded from solvent by the polypeptide backbone, and in some algae and cyanobacteria by Fld, which employs a flavin as prosthetic group and is tolerant to oxidants and iron limitation. Tight membrane binding of FNR allowed solid-state electron transfer from PSI bridged by Fd/Fld. Fine tuning of FNR catalytic mechanism led to formidable increases in turnover rates compared with FNRs acting in heterotrophic pathways, favoring Fd/Fld reduction instead of oxygen reduction.