ATP binding is critical for the conformational change from an open to closed state in archaeal group II chaperonin
ATP binding is critical for the conformational change from an open to closed state in archaeal group II chaperonin
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DOI：
10.1074/jbc.m305484200
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发表时间：
2003-11-07
影响因子：
4.8
通讯作者：
Yohda, M
中科院分区：
文献类型：
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作者：
Iizuka, R;Yoshida, T;Yohda, M
在古细菌和真核细胞质中发现的II族伴侣蛋白没有与GroES相对应的共同伴侣蛋白。相反，有人认为，从顶端区域延伸出来的螺旋状突起充当了中心腔的内置盖子，盖子的打开和关闭是由ATP结合和水解调节的。然而，这种构象变化的细节仍不清楚。为了研究与atp驱动周期相关的构象变化，我们对嗜热古细菌热球菌菌株KS-1的α -伴蛋白进行了蛋白酶敏感性分析和色氨酸荧光光谱分析。在无核苷酸或adp结合状态下，伴侣蛋白，特别是在螺旋突起区，对蛋白酶高度敏感。ATP和硫酸铵的加入诱导其转变为相对耐蛋白酶的形态。在三磷酸腺苷或硫酸铵的存在下，在螺旋突起尖端引入的色氨酸残基的荧光强度增强。我们得出结论，ATP结合诱导了古细菌II族伴侣蛋白从开盖到闭盖的构象变化。
Group II chaperonins, found in archaea and in eukaryotic cytosol, do not have a co-chaperonin corresponding to GroES. Instead, it is suggested that the helical protrusion extending from the apical domain acts as a built-in lid for the central cavity and that the opening and closing of the lid is regulated by ATP binding and hydrolysis. However, details of this conformational change remain unclear. To investigate the conformational change associated with the ATP-driven cycle, we conducted protease sensitivity analyses and tryptophan fluorescence spectroscopy of alpha-chaperonin from a hyperthermophilic archaeum, Thermococcus strain KS-1. In the nucleotide-free or ADP-bound state, the chaperonin, especially in the helical protrusion region, was highly sensitive to proteases. Addition of ATP and ammonium sulfate induced the transition to the relatively protease-resistant form. The fluorescence intensity of the tryptophan residue introduced at the tip of the helical protrusion was enhanced by the presence of ATP or ammonium sulfate. We conclude that ATP binding induces the conformational change from the lid-open to lid-closed form in archaeal group II chaperonin.