Gatti D L, Tarr G, Fee J A, Ackerman S H
Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
J Bioenerg Biomembr. 1998 Jun;30(3):223-33. doi: 10.1023/a:1020540702567.
The structural gene encoding the Rieske iron-sulfur protein from Thermus thermophilus HB8 has been cloned and sequenced. The gene encodes a protein of 209 amino acids that begins with a hydrophilic N-terminus followed by a stretch of 21 hydrophobic amino acids that could serve as a transmembrane helix. The remainder of the protein has a hydrophobicity pattern typical of a water-soluble protein. A phylogenetic analysis of 26 Rieske proteins that are part of bc1 or b6f complexes shows that they fall into three major groups: eubacterial and mitochondrial, cyanobacterial and plastid, and five highly divergent outliers, including that of Thermus. Although the overall homology with other Rieske proteins is very low, the C-terminal half of the Thermus protein contains the signature sequence CTHLGC-(13X)-CPCH that most likely provides the ligands of the [2Fe-2S] cluster. It is proposed that this region of the protein represents a small domain that folds independently and that the encoding DNA sequence may have been transferred during evolution to several unrelated genes to provide the cluster attachment site to proteins of different origin. The role of individual residues in this domain of the Thermus protein is discussed vis-a-vis the three-dimensional structure of the bovine protein (Iwata et al., 1996 Structure 4, 567-579).
嗜热栖热菌HB8中编码 Rieske 铁硫蛋白的结构基因已被克隆和测序。该基因编码一个由209个氨基酸组成的蛋白质，其起始为亲水性的N端，接着是一段21个疏水氨基酸的序列，这段序列可能作为跨膜螺旋。该蛋白质的其余部分具有水溶性蛋白质典型的疏水性模式。对bc1或b6f复合物中26种 Rieske 蛋白进行的系统发育分析表明，它们可分为三大类：真细菌和线粒体类、蓝细菌和质体类，以及五个高度分化的异常值，包括嗜热栖热菌的Rieske蛋白。尽管与其他 Rieske 蛋白的总体同源性很低，但嗜热栖热菌蛋白的C端一半包含特征序列CTHLGC-(13X)-CPCH，该序列很可能提供了[2Fe-2S]簇的配体。有人提出，该蛋白质的这一区域代表一个独立折叠的小结构域，并且编码该结构域的DNA序列在进化过程中可能已转移至几个不相关的基因，以便为不同来源的蛋白质提供簇附着位点。针对牛蛋白的三维结构（Iwata等人，1996年，《结构》4卷，567 - 579页），讨论了嗜热栖热菌蛋白这一结构域中各个残基的作用。
