The bacterial flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase complex derived from Burkholderia cepacia (BcGDH) is a representative molecule of direct electron transfer-type FAD-dependent dehydrogenase complexes. In this study, the X-ray structure of BcGDHγα, the catalytic subunit (α-subunit) of BcGDH complexed with a hitchhiker protein (γ-subunit), was determined. The most prominent feature of this enzyme is the presence of the 3Fe-4S cluster, which is located at the surface of the catalytic subunit and functions in intramolecular and intermolecular electron transfer from FAD to the electron-transfer subunit. The structure of the complex revealed that these two molecules are connected through disulfide bonds and hydrophobic interactions, and that the formation of disulfide bonds is required to stabilize the catalytic subunit. The structure of the complex revealed the putative position of the electron-transfer subunit. A comparison of the structures of BcGDHγα and membrane-bound fumarate reductases suggested that the whole BcGDH complex, which also includes the membrane-bound β-subunit containing three heme c moieties, may form a similar overall structure to fumarate reductases, thus accomplishing effective electron transfer.

中文翻译：

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与搭便车蛋白复合的直接电子转移型 FAD 葡萄糖脱氢酶催化亚基的 X 射线结构。


源自洋葱伯克霍尔德菌(BcGDH)的细菌黄素腺嘌呤二核苷酸(FAD)依赖性葡萄糖脱氢酶复合物是直接电子转移型FAD依赖性脱氢酶复合物的代表分子。在本研究中，确定了 BcGDHγα（BcGDH 的催化亚基（α 亚基）与搭便车蛋白（γ 亚基）复合物）的 X 射线结构。该酶最显着的特征是存在 3Fe-4S 簇，该簇位于催化亚基的表面，在从 FAD 到电子转移亚基的分子内和分子间电子转移中发挥作用。该复合物的结构表明，这两个分子通过二硫键和疏水相互作用连接，并且需要二硫键的形成来稳定催化亚基。复合物的结构揭示了电子转移亚基的假定位置。 BcGDHγα和膜结合富马酸还原酶的结构比较表明，整个BcGDH复合物，其中还包括含有三个血红素c部分的膜结合β亚基，可能形成与富马酸还原酶相似的整体结构，从而实现有效电子转移。