Diverse reaction behaviors of artificial ubiquinones in mitochondrial respiratory complex I.
Diverse reaction behaviors of artificial ubiquinones in mitochondrial respiratory complex I.
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人工泛醌在线粒体呼吸复合体I中的多种反应行为。
DOI：
10.1016/j.jbc.2022.102075
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发表时间：
2022-07
影响因子：
4.8
通讯作者：
Miyoshi, Hideto
中科院分区：
文献类型：
--
作者：
Uno, Shinpei;Masuya, Takahiro;Zdorevskyi, Oleksii;Ikunishi, Ryo;Shinzawa-Itoh, Kyoko;Lasham, Jonathan;Sharma, Vivek;Murai, Masatoshi;Miyoshi, Hideto
NADH-UQ 氧化还原酶（线粒体呼吸复合物 I）催化的泛醌 (UQ) 还原步骤是触发质子跨线粒体内膜易位的关键。结构研究已经在酶内发现了一条又长又窄、通往昆士兰大学的通道。我们之前证明，合成的超大 UQ 不太可能通过这条狭窄的隧道，可以被嵌入软骨下颗粒中的天然复合物 I 催化还原，但不能被分离的酶催化还原。为了解释这一矛盾，我们假设在分离的酶中，过大的 UQ 进入反应位点受到阻碍，因为它们的进入途径在线粒体内膜溶解去垢剂后发生了改变。在本研究中，我们使用两对光反应性 UQ（pUQm-1/pUQp-1 和 pUQm-2/pUQp-2）对此进行了研究，每对具有相同的化学性质，除了侧链宽度有 ∼1.0 Å 的差异。尽管存在这种细微的差异，但分离的复合物对较宽 pUQ 的还原速度明显慢于较窄 pUQ，但两者均被天然酶类似地还原。此外，使用四种 [125I]pUQ 的光亲和标记实验表明，它们的侧链主要用两种酶标记 ND1 亚基，但位于隧道周围的不同区域。最后，我们表明，不同类型的抑制剂对标记的抑制作用根据所使用的[125I]pUQ而显着变化，这表明[125I]pUQ和这些抑制剂不一定共享共同的结合腔。总而言之，我们得出结论，pUQ 的反应行为不能简单地用规范的 UQ 隧道模型来解释。
The ubiquinone (UQ) reduction step catalyzed by NADH-UQ oxidoreductase (mitochondrial respiratory complex I) is key to triggering proton translocation across the inner mitochondrial membrane. Structural studies have identified a long, narrow, UQ-accessing tunnel within the enzyme. We previously demonstrated that synthetic oversized UQs, which are unlikely to transit this narrow tunnel, are catalytically reduced by native complex I embedded in submitochondrial particles but not by the isolated enzyme. To explain this contradiction, we hypothesized that access of oversized UQs to the reaction site is obstructed in the isolated enzyme because their access route is altered following detergent solubilization from the inner mitochondrial membrane. In the present study, we investigated this using two pairs of photoreactive UQs (pUQm-1/pUQp-1 and pUQm-2/pUQp-2), with each pair having the same chemical properties except for a ∼1.0 Å difference in side-chain widths. Despite this subtle difference, reduction of the wider pUQs by the isolated complex was significantly slower than of the narrower pUQs, but both were similarly reduced by the native enzyme. In addition, photoaffinity-labeling experiments using the four [125I]pUQs demonstrated that their side chains predominantly label the ND1 subunit with both enzymes but at different regions around the tunnel. Finally, we show that the suppressive effects of different types of inhibitors on the labeling significantly changed depending on [125I]pUQs used, indicating that [125I]pUQs and these inhibitors do not necessarily share a common binding cavity. Altogether, we conclude that the reaction behaviors of pUQs cannot be simply explained by the canonical UQ tunnel model.
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影响因子：
64.8
作者：
Fiedorczuk, Karol;Letts, James A.;Degliesposti, Gianluca;Kaszuba, Karol;Skehel, Mark;Sazanov, Leonid A.
通讯作者：
Sazanov, Leonid A.
影响因子：
16.6
作者：
通讯作者：
--
影响因子：
16.6
作者：
Bridges HR;Fedor JG;Blaza JN;Di Luca A;Jussupow A;Jarman OD;Wright JJ;Agip AA;Gamiz-Hernandez AP;Roessler MM;Kaila VRI;Hirst J
通讯作者：
Hirst J
影响因子：
4.3
作者：
Galassi, Vanesa Viviana;Arantes, Guilherme Menegon
通讯作者：
Arantes, Guilherme Menegon
影响因子：
15
作者：
Gamiz-Hernandez AP;Jussupow A;Johansson MP;Kaila VRI
通讯作者：
Kaila VRI