Solution NMR structure of yeast Rcf1, a protein involved in respiratory supercomplex formation
Solution NMR structure of yeast Rcf1, a protein involved in respiratory supercomplex formation
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DOI：
10.1073/pnas.1712061115
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发表时间：
2018-03-20
影响因子：
11.1
通讯作者：
Adelroth, Pia
中科院分区：
文献类型：
--
作者：
Zhou, Shu;Pettersson, Pontus;Adelroth, Pia
酿酒酵母呼吸超复合体因子1(Rcf1)蛋白位于线粒体内膜，参与呼吸复合体III和IV组成的超复合体的形成。我们报道了Rcf1的溶液结构，它在十二烷基磷胆碱(DPC)胶束中形成二聚体，每个单体由五个跨膜(TM)螺旋和一个短的柔性可溶螺旋(SH)组成。三个TM螺旋是异常带电的，并提供了由10个假定的盐桥组成的二聚化界面，定义了一个“电荷拉链”基序。DPC中的分子动力学(MD)模拟支持二聚体结构，尽管模拟显示了比核磁共振数据更动态的二聚体界面。此外，CD和核磁共振数据表明，RCF1在脂质体中重组时发生了结构变化，这一点得到了MD数据的支持，表明二聚体结构在平面膜环境中是不稳定的。总而言之，这些数据表明了一个动态的单体-二聚体平衡。此外，RCF1二聚体与细胞色素c相互作用，表明RCF1二聚体在复合体III和IV之间起着电子转移桥梁的作用。RCF1的结构将有助于在分子水平上理解其功能作用。
The Saccharomyces cerevisiae respiratory supercomplex factor 1 (Rcf1) protein is located in the mitochondrial inner membrane where it is involved in formation of supercomplexes composed of respiratory complexes III and IV. We report the solution structure of Rcf1, which forms a dimer in dodecylphosphocholine (DPC) micelles, where each monomer consists of a bundle of five transmembrane (TM) helices and a short flexible soluble helix (SH). Three TM helices are unusually charged and provide the dimerization interface consisting of 10 putative salt bridges, defining a "charge zipper" motif. The dimer structure is supported by molecular dynamics (MD) simulations in DPC, although the simulations show a more dynamic dimer interface than the NMR data. Furthermore, CD and NMR data indicate that Rcf1 undergoes a structural change when reconstituted in liposomes, which is supported by MD data, suggesting that the dimer structure is unstable in a planar membrane environment. Collectively, these data indicate a dynamic monomer-dimer equilibrium. Furthermore, the Rcf1 dimer interacts with cytochrome c, suggesting a role as an electron-transfer bridge between complexes III and IV. The Rcf1 structure will help in understanding its functional roles at a molecular level.