Crystal structure of the Apo forms of Ψ55 tRNA pseudouridine synthase from Mycobacterium tuberculosis -: A hinge at the base of the catalytic cleft
Crystal structure of the Apo forms of Ψ55 tRNA pseudouridine synthase from Mycobacterium tuberculosis -: A hinge at the base of the catalytic cleft
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DOI：
10.1074/jbc.m401045200
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发表时间：
2004-06-04
影响因子：
4.8
通讯作者：
Yeates, TO
中科院分区：
文献类型：
--
作者：
Chaudhuri, BN;Sum, C;Yeates, TO
报道了来自结核分枝杆菌的 RNA 修饰酶 Psi55 tRNA 假尿苷合酶的三维结构。 1.9 埃分辨率的晶体结构揭示了酶，不含底物，具有两种不同的构象。该结构描绘了一种有趣的蛋白质柔性模式，涉及催化模块中央β片层的铰链弯曲。还发现酶的无底物形式的活性位点裂缝的关键部分是无序的。铰链弯曲似乎充当定位基板的夹具。我们的结构数据进一步推进了之前提出的 tRNA 识别机制。目前的晶体结构强调了蛋白质动力学在 tRNA 识别、碱基翻转和修饰中必须发挥的重要作用。
The three-dimensional structure of the RNA-modifying enzyme, Psi55 tRNA pseudouridine synthase from Mycobacterium tuberculosis, is reported. The 1.9-Angstrom resolution crystal structure reveals the enzyme, free of substrate, in two distinct conformations. The structure depicts an interesting mode of protein flexibility involving a hinged bending in the central beta-sheet of the catalytic module. Key parts of the active site cleft are also found to be disordered in the substrate-free form of the enzyme. The hinge bending appears to act as a clamp to position the substrate. Our structural data furthers the previously proposed mechanism of tRNA recognition. The present crystal structure emphasizes the significant role that protein dynamics must play in tRNA recognition, base flipping, and modification.