Rapp Mikaela, Seppälä Susanna, Granseth Erik, von Heijne Gunnar
Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
Science. 2007 Mar 2;315(5816):1282-4. doi: 10.1126/science.1135406. Epub 2007 Jan 25.
How do integral membrane proteins evolve in size and complexity? Using the small multidrug-resistance protein EmrE from Escherichia coli as a model, we experimentally demonstrated that the evolution of membrane proteins composed of two homologous but oppositely oriented domains can occur in a small number of steps: An original dual-topology protein evolves, through a gene-duplication event, to a heterodimer formed by two oppositely oriented monomers. This simple evolutionary pathway can explain the frequent occurrence of membrane proteins with an internal pseudo-two-fold symmetry axis in the plane of the membrane.
整合膜蛋白是如何在大小和复杂性上进化的？我们以大肠杆菌中的小多药耐药蛋白EmrE为模型，通过实验证明，由两个同源但方向相反的结构域组成的膜蛋白可以在少数几个步骤中进化：一个原始的双拓扑蛋白通过基因复制事件进化为一个由两个方向相反的单体形成的异二聚体。这种简单的进化途径可以解释膜平面内具有内部假二重对称轴的膜蛋白频繁出现的现象。
