Klumpp M, Baumeister W, Essen L O
Department of Molecular Structural Biology, Max-Planck-Institute for Biochemistry, Planegg-Martinsried, Germany.
Cell. 1997 Oct 17;91(2):263-70. doi: 10.1016/s0092-8674(00)80408-0.
The crystal structure of the substrate binding domain of the thermosome, the archaeal group II chaperonin, has been determined at 2.3 A resolution. The core resembles the apical domain of GroEL but lacks the hydrophobic residues implied in binding of substrates to group I chaperonins. Rather, a large hydrophobic surface patch is found in a novel helix-turn-helix motif, which is characteristic of all group II chaperonins including the eukaryotic TRiC/CCT complex. Models of the holochaperonin, which are consistent with cryo electron microscopy data, suggest a dual role of this helical protrusion in substrate binding and controlling access to the central cavity independent of a GroES-like cochaperonin.
已通过2.3埃分辨率确定了嗜热体（古菌第二组伴侣蛋白）底物结合结构域的晶体结构。其核心类似于GroEL的顶端结构域，但缺少与第一组伴侣蛋白结合底物相关的疏水残基。相反，在一个新颖的螺旋-转角-螺旋基序中发现了一个大的疏水表面斑块，这是包括真核生物TRiC/CCT复合物在内的所有第二组伴侣蛋白的特征。与冷冻电子显微镜数据一致的全伴侣蛋白模型表明，这种螺旋突出物在底物结合和控制进入中央腔方面具有双重作用，且不依赖于类似GroES的共伴侣蛋白。
