Pathare Ganesh Ramnath, Nagy István, Hubert Ágnes, Thomas Dennis R, Bracher Andreas
Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Acta Crystallogr F Struct Biol Commun. 2017 Jun 1;73(Pt 6):328-335. doi: 10.1107/S2053230X17007087. Epub 2017 May 25.
The crystal structure of the Ta1207 protein from Thermoplasma acidophilum is reported. Ta1207 was identified in a screen for high-molecular-weight protein complexes in T. acidophilum. In solution, Ta1207 forms homopentamers of 188 kDa. The crystal structure of recombinant Ta1207 solved by Se-MAD at 2.4 Å resolution revealed a complex with fivefold symmetry. In the crystal lattice, calcium ions induce the formation of a nanocage from two pentamers. The Ta1207 protomers comprise two domains with the same novel α/β topology. A deep pocket with a binding site for a negatively charged group suggests that Ta1207 functions as an intracellular receptor for an unknown ligand. Homologues of Ta1207 occur only in Thermoplasmatales and its function might be related to the extreme lifestyle of these archaea. The thermostable Ta1207 complex might provide a useful fivefold-symmetric scaffold for future nanotechnological applications.
报道了嗜酸嗜热栖热菌（Thermoplasma acidophilum）中Ta1207蛋白的晶体结构。Ta1207是在嗜酸嗜热栖热菌高分子量蛋白复合物筛选中鉴定出来的。在溶液中，Ta1207形成188 kDa的同五聚体。通过硒单波长反常散射（Se-MAD）以2.4 Å分辨率解析的重组Ta1207晶体结构显示出具有五重对称性的复合物。在晶格中，钙离子诱导两个五聚体形成一个纳米笼。Ta1207原体包含两个具有相同新型α/β拓扑结构的结构域。一个带有负电荷基团结合位点的深口袋表明Ta1207作为一种未知配体的细胞内受体发挥作用。Ta1207的同源物仅存在于嗜热栖热菌目（Thermoplasmatales）中，其功能可能与这些古菌的极端生活方式有关。热稳定的Ta1207复合物可能为未来的纳米技术应用提供一个有用的五重对称支架。
