Molecular mechanism of negative cooperativity of ferredoxin-NADP+ reductase by ferredoxin and NADP(H): involvement of a salt bridge between Asp60 of ferredoxin and Lys33 of FNR
Molecular mechanism of negative cooperativity of ferredoxin-NADP+ reductase by ferredoxin and NADP(H): involvement of a salt bridge between Asp60 of ferredoxin and Lys33 of FNR
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DOI：
10.1093/bbb/zbaa102
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发表时间：
2021-03-24
影响因子：
1.6
通讯作者：
Kimata-Ariga, Yoko
中科院分区：
文献类型：
--
作者：
Chikuma, Yutaro;Miyata, Masayuki;Kimata-Ariga, Yoko
植物中的铁氧化还蛋白-NADP（+）还原酶（FNR）在光合作用电子传递链的末端接受来自铁氧化还蛋白（Fd）的电子并将NADP（+）转化为NADPH。我们之前的研究表明，NADP(H)在FNR上的变构结合削弱了FNR和Fd之间的相互作用，这被认为是负协同作用的一部分。在这项研究中，我们利用玉米FNR和Fd研究了这一现象的分子机制，因为Fd:FNR复合物的三维结构是可用的。核磁共振化学位移微扰分析发现，Fd分子上有一个位点（Asp60）受到NADP(H)与FNR结合的选择性影响。Fd的Asp60与FNR的Lys33在复合物中形成盐桥。FdD60和FNRK33位点特异性突变体抑制了负协同性（NADPH下调FNR和Fd之间的相互作用），表明FdD60和FNRK33之间的盐桥参与了这种负协同性。
Ferredoxin-NADP(+) reductase (FNR) in plants receives electrons from ferredoxin (Fd) and converts NADP(+) to NADPH at the end of the photosynthetic electron transfer chain. We previously showed that the interaction between FNR and Fd was weakened by the allosteric binding of NADP(H) on FNR, which was considered as a part of negative cooperativity. In this study, we investigated the molecular mechanism of this phenomenon using maize FNR and Fd, as the three-dimensional structure of this Fd:FNR complex is available. NMR chemical shift perturbation analysis identified a site (Asp60) on Fd molecule which was selectively affected by NADP(H) binding on FNR. Asp60 of Fd forms a salt bridge with Lys33 of FNR in the complex. Site-specific mutants of FdD60 and FNRK33 suppressed the negative cooperativity (downregulation of the interaction between FNR and Fd by NADPH), indicating that a salt bridge between FdD60 and FNRK33 is involved in this negative cooperativity.