1] Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France. [2] Institut de Biologie Structurale, Centre National de la Recherche Scientifique, Grenoble, France. [3] Institut de Biologie Structurale, Commissariat à l'Énergie Atomique (CEA), Grenoble, France. [4] Laboratory for Advanced Studies of Membrane Proteins, Moscow Institute of Physics and Technology, Dolgoprudniy, Russia. [5] Institute of Complex Systems (ICS), ICS-6, Structural Biochemistry, Research Center Jülich, Jülich, Germany.
1] Laboratory for Advanced Studies of Membrane Proteins, Moscow Institute of Physics and Technology, Dolgoprudniy, Russia. [2] Institute of Complex Systems (ICS), ICS-6, Structural Biochemistry, Research Center Jülich, Jülich, Germany. [3] Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany.
Nat Struct Mol Biol. 2015 May;22(5):390-5. doi: 10.1038/nsmb.3002. Epub 2015 Apr 6.
Recently, the first known light-driven sodium pumps, from the microbial rhodopsin family, were discovered. We have solved the structure of one of them, Krokinobacter eikastus rhodopsin 2 (KR2), in the monomeric blue state and in two pentameric red states, at resolutions of 1.45 Å and 2.2 and 2.8 Å, respectively. The structures reveal the ion-translocation pathway and show that the sodium ion is bound outside the protein at the oligomerization interface, that the ion-release cavity is capped by a unique N-terminal α-helix and that the ion-uptake cavity is unexpectedly large and open to the surface. Obstruction of the cavity with the mutation G263F imparts KR2 with the ability to pump potassium. These results pave the way for the understanding and rational design of cation pumps with new specific properties valuable for optogenetics.
最近，人们发现了首个已知的由微生物视紫红质家族驱动的光泵。我们已经解析了其中一种的结构，即嗜酸红假单胞菌视紫红质 2（KR2），分别在单体蓝色状态和两个五聚体红色状态下达到了 1.45 Å、2.2 Å 和 2.8 Å 的分辨率。这些结构揭示了离子转运途径，并表明钠离子在寡聚化界面处结合在蛋白外部，离子释放腔由独特的 N 端 α-螺旋封闭，而离子摄取腔出人意料地大且向表面开放。用突变 G263F 阻塞腔赋予 KR2 泵出钾离子的能力。这些结果为理解和合理设计具有新特性的阳离子泵铺平了道路，这些特性对视遗传学具有重要价值。
