High-resolution structure of the soluble, respiratory-type Rieske protein from Thermus thermophilus:: analysis and comparison
High-resolution structure of the soluble, respiratory-type Rieske protein from Thermus thermophilus:: analysis and comparison
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DOI：
10.1021/bi0342719
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发表时间：
2003-06-24
期刊：
影响因子：
2.9
通讯作者：
Fee, JA
中科院分区：
文献类型：
--
作者：
Hunsicker-Wang, LM;Heine, A;Fee, JA
用多波长反常色散(MAD)技术测定了嗜热嗜热菌可溶性Rieske蛋白的结构，其分辨率为1.3埃，pH为8.5。这是首次报道从一种利用菜籽酮的有机体中提取的Rieske蛋白。该结构显示出与先前报道的Rieske蛋白相似的整体折叠。这种晶型的一个新特征似乎是连接到[2Fe-2S]簇的Fe2上的His-134咪唑环和它的对称伙伴His-134‘之间共享一个氢，其中His-134’形式上是咪唑类阴离子，Fe2-(His-134)Nepsilon(-)...H-Nepsilon‘-(His-134’)-Fe2‘，，其中晶体C-2轴在尼泊尔硅酮...尼泊尔硅隆’和垂直于由尼泊尔硅隆定义的线...尼泊尔硅隆‘之间等距离移动。这为具有组氨酸(-)配体的稳定、氧化的团簇提供了证据，并支持了先前提出的质子和电子耦合转移的机制。Thermus Rieske蛋白与其他六种Rieske和Rieske类型蛋白的详细比较表明：(A)簇结合结构域是紧密保守的。(B)10个β-链折叠的三维结构是保守的，即使在最分化的蛋白质中也是如此。(C)酸-pH氧化还原电位与原子团簇上的氢键数目近似成线性关系。(D)这些蛋白质有两个面，一个指向较大的复合体(bc(1)、b(6)f或其他)，参与质子耦合电子转移功能，并且高度保守。第二个方向是指向溶剂，在电荷、序列、长度、疏水性和连接β-折叠的环中的次要元素方面显示出广泛的变化。
The structure of the soluble Rieske protein from Thermus thermophilus has been determined at a resolution of 1.3 Angstrom at pH 8.5 using multiwavelength anomalous dispersion (MAD) techniques. This is the first report of a Rieske protein from a menaquinone-utilizing organism. The structure shows an overall fold similar to previously reported Rieske proteins. A novel feature of this crystal form appears to be a shared hydrogen between the His-134 imidazole ring ligated to Fe2 of the [2Fe-2S] cluster and its symmetry partner, His-134', one being formally an imidazolate anion, Fe2-(His-134)Nepsilon(-)...H-Nepsilon'-(His-134')-Fe2', in which crystallographic C-2 axes pass equidistant between Nepsilon...Nepsilon' and normal to the line defined by Nepsilon...Nepsilon'. This provides evidence for a stable, oxidized cluster with a His(-) ligand and lends support to a previously proposed mechanism of coupled proton and electron transfer. A detailed comparison of the Thermus Rieske protein with six other Rieske and Rieske-type proteins indicates: (a) The cluster binding domain is tightly conserved. (b) The 3-D structure of the 10 beta-strand fold is conserved, even among the most divergent proteins. (c) There is an approximately linear relation between acid-pH redox potential and number of H-bonds to the cluster. (d) These proteins have two faces, one points into the larger complex (bc(1), b(6)f, or other), is involved in the proton coupled electron transfer function, and is highly conserved. The second is oriented toward the solvent and shows wide variation in charge, sequence, length, hydrophobicity, and secondary elements in the loops that connect the beta-sheets.