Ditzel L, Löwe J, Stock D, Stetter K O, Huber H, Huber R, Steinbacher S
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Cell. 1998 Apr 3;93(1):125-38. doi: 10.1016/s0092-8674(00)81152-6.
We have determined to 2.6 A resolution the crystal structure of the thermosome, the archaeal group II chaperonin from T. acidophilum. The hexadecameric homolog of the eukaryotic chaperonin CCT/TRiC shows an (alphabeta)4(alphabeta)4 subunit assembly. Domain folds are homologous to GroEL but form a novel type of inter-ring contact. The domain arrangement resembles the GroEL-GroES cis-ring. Parts of the apical domains form a lid creating a closed conformation. The lid substitutes for a GroES-like cochaperonin that is absent in the CCT/TRiC system. The central cavity has a polar surface implicated in protein folding. Binding of the transition state analog Mg-ADP-AIF3 suggests that the closed conformation corresponds to the ATP form.
我们已将嗜热栖热菌的古菌Ⅱ型伴侣蛋白——热体的晶体结构解析至2.6埃分辨率。真核伴侣蛋白CCT/TRiC的十六聚体同源物呈现出(αβ)4(αβ)4亚基组装形式。其结构域折叠与GroEL同源，但形成了一种新型的环间接触。结构域排列类似于GroEL - GroES顺式环。顶端结构域的部分区域形成一个盖子，产生封闭构象。该盖子替代了CCT/TRiC系统中不存在的类似GroES的共伴侣蛋白。中央腔具有与蛋白质折叠相关的极性表面。过渡态类似物Mg - ADP - AIF3的结合表明，封闭构象对应于ATP形式。
