Binding of ferredoxin to algal photosystem I involves a single binding site and is composed of two thermodynamically distinct events
Binding of ferredoxin to algal photosystem I involves a single binding site and is composed of two thermodynamically distinct events
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DOI：
10.1016/j.bbabio.2018.01.001
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发表时间：
2018-04-01
影响因子：
4.3
通讯作者：
Yacoby, Iftach
中科院分区：
文献类型：
--
作者：
Marco, Pini;Kozuleva, Marina;Yacoby, Iftach
尽管近年来在理解光合作用反应中心内电荷分离的早期步骤方面取得了令人印象深刻的进展，但我们对铁还蛋白(FD)如何与光系统I(PSI)的受体端相互作用的了解还不够深入。Fd在瞬时对接到PSI受体一侧的结合位点后接受电子。然而，20多年来，这种结合的确切位置以及化学计量一直是一个有争议的问题。在这里，利用恒温滴定量热法(ITC)和绿藻衣藻野生型和突变株的纯化组分，我们证明了PSI与Fd只有一个结合部位，并且这种结合由两个不同的结合事件组成，每个结合事件都有一个特定的结合常数。
Despite the impressive progress made in recent years in understanding the early steps in charge separation within the photosynthetic reaction centers, our knowledge of how ferredoxin (Fd) interacts with the acceptor side of photosystem I (PSI) is not as well developed. Fd accepts electrons after transiently docking to a binding site on the acceptor side of PSI. However, the exact location, as well as the stoichiometry, of this binding have been a matter of debate for more than two decades. Here, using Isothermal Titration Calorimetry (ITC) and purified components from wild type and mutant strains of the green algae Chlamydomonas reinhardtii we show that PSI has a single binding site for Fd, and that the association consists of two distinct binding events, each with a specific association constant.