A conformationally restricted guanosine analog reveals the catalytic relevance of three structures of an RNA enzyme.
A conformationally restricted guanosine analog reveals the catalytic relevance of three structures of an RNA enzyme.
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DOI：
10.1016/j.chembiol.2006.11.004
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发表时间：
2007
影响因子：
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通讯作者：
R. Yajima;David J. Proctor;R. Kierzek;E. Kierzek;P. Bevilacqua
中科院分区：
文献类型：
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作者：
R. Yajima;David J. Proctor;R. Kierzek;E. Kierzek;P. Bevilacqua
最近的研究表明，RNA的功能可以通过掺入构象受限的核苷酸来增强。在这里，我们使用8-溴鸟苷，一种具有强制合成构象的核苷酸类似物，来阐明核酶结构的催化相关性。我们之所以选择研究铅依赖的核酶(Leadzyme)，是因为从核磁共振、晶体和计算(MC-Sym)研究得出的结构模型不同，三个活性中心鸟苷(G7、G9或G24)中的哪一个具有不同的糖苷扭转角。在这三个鸟苷位置对8BrG变异体进行了动力学分析。这些数据表明8BrG24铅酶活性过高，而8BrG7和8BrG9铅酶活性降低。这些发现支持铅酶的计算模型，而不是核磁共振和晶体结构，因为这与磷酸二酯键断裂最相关。
Recent studies indicate that RNA function can be enhanced by the incorporation of conformationally restricted nucleotides. Herein, we use 8-bromoguanosine, a nucleotide analog with an enforcedsynconformation, to elucidate the catalytic relevance of ribozyme structures. We chose to study the lead-dependent ribozyme (leadzyme) because structural models derived from NMR, crystal, and computational (MC-Sym) studies differ in which of the three active site guanosines (G7, G9, or G24) have asynglycosidic torsion angle. Kinetic assays were carried out on 8BrG variants at these three guanosine positions. These data indicate that an 8BrG24 leadzyme is hyperactive, while 8BrG7 and 8BrG9 leadzymes have reduced activity. These findings support the computational model of the leadzyme, rather than the NMR and crystal structures, as being the most relevant to phosphodiester bond cleavage.