Structural basis of RNA-dependent recruitment of glutamine to the genetic code
Structural basis of RNA-dependent recruitment of glutamine to the genetic code
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DOI：
10.1126/science.1128470
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发表时间：
2006-06-30
期刊：
影响因子：
56.9
通讯作者：
Nureki, Osamu
中科院分区：
文献类型：
--
作者：
Oshikane, Hiroyuki;Sheppard, Kelly;Nureki, Osamu
古生菌中的谷氨酰转移RNA(Gln-tRNA，Gln)是在异源二聚体Glu-tRNA(Gln)氨基转移酶GatDE的作用下，由错酰化的Gln-tRNA(Gln)在翻译前合成的。本文报道了在3.15埃分辨率下，热营养甲烷杆菌GatDE与tRNA(Gln)络合的晶体结构。GatDE和tRNAGln突变体的生化分析表征了酶的三个反应(谷氨酰胺酶、激酶和氨基转移酶活性)的催化中心。一条40埃长的氨转运通道连接了GatD和GATE中的活性中心。基于D环的形状互补的间接读出识别tRNA(Gln)表明了一种早期的基于反密码子的RNA机制，用于将谷氨酰胺添加到遗传密码中。
Glutaminyl-transfer RNA (Gln-tRNA(Gln)) in archaea is synthesized in a pretranslational amidation of misacylated Glu-tRNA(Gln) by the heterodimeric Glu-tRNA(Gln) amidotransferase GatDE. Here we report the crystal structure of the Methanothermobacter thermautotrophicus GatDE complexed to tRNA(Gln) at 3.15 angstroms resolution. Biochemical analysis of GatDE and of tRNAGln mutants characterized the catalytic centers for the enzyme's three reactions (glutaminase, kinase, and amidotransferase activity). A 40 angstrom-long channel for ammonia transport connects the active sites in GatD and GatE. tRNA(Gln) recognition by indirect readout based on shape complementarity of the D loop suggests an early anticodon-independent RNA-based mechanism for adding glutamine to the genetic code.