Role of Histidine 78 of leaf ferredoxin in the interaction with ferredoxin-NADP+ reductase: regulation of pH dependency and negative cooperativity with NADP(H)
Role of Histidine 78 of leaf ferredoxin in the interaction with ferredoxin-NADP+ reductase: regulation of pH dependency and negative cooperativity with NADP(H)
复制标题
叶铁氧还蛋白组氨酸 78 在与铁氧还蛋白-NADP 还原酶相互作用中的作用：pH 依赖性调节和与 NADP(H) 的负协同性
DOI：
10.1093/bbb/zbac022
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Miyata Masayuki
中科院分区：
文献类型：
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作者：
Kimata-Ariga Yoko;Fukuta Karen;Miyata Masayuki
在叶绿体基质中，响应于波动的光条件而发生动态pH变化。研究了玉米叶片铁氧还蛋白-NADP+还原酶（FNR）和铁氧还蛋白（Fd）同功蛋白之间pH依赖的电子传递活性。随着pH值的升高（从5.5到8.5），FNR向光合型Fd（Fd 1）的电子传递活性显著增加，而向非光合型Fd（Fd 3）的电子传递活性显著降低，这主要是由于Fd对Km的pH依赖性不同所致。Fd 1的His 78突变为Fd 3的相应氨基酸残基瓦尔，使Fd 3的pH依赖性丧失，表明His 78在与FNR的相互作用中具有调节作用。我们以前发现，FNR和Fd之间的相互作用被NADP（H）对FNR的变构结合所削弱。His 78 Val Fd 1突变体在很大程度上抑制了这种负协同效应。这些结果表明Fd 1 His 78参与pH依赖性和与FNR相互作用的负协同性。
In chloroplast stroma, dynamic pH change occurs in response to fluctuating light conditions. We investigated the pH-dependent electron transfer activity between ferredoxin-NADP+reductase (FNR) and ferredoxin (Fd) isoproteins from maize leaves. By increasing pH (from 5.5 to 8.5), the electron transfer activity from FNR to photosynthetic-type Fd (Fd1) significantly increased while the activity to nonphotosynthetic type Fd (Fd3) decreased, which was mainly due to their differences in the pH dependency ofKmfor Fd. Mutation of His78 of Fd1 to Val, corresponding amino acid residue in Fd3, lost the pH dependency, indicating a regulatory role of the His78 in the interaction with FNR. We previously showed that the interaction between FNR and Fd was weakened by the allosteric binding of NADP(H) on FNR. His78Val Fd1 mutant largely suppressed this negative cooperativity. These results indicate the involvement of Fd1 His78 in pH dependency and negative cooperativity in the interaction with FNR.