tRNA recognition by glutamyl-tRNA reductase
tRNA recognition by glutamyl-tRNA reductase
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DOI：
10.1074/jbc.m401529200
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发表时间：
2004-08-13
影响因子：
4.8
通讯作者：
Jahn, D
中科院分区：
文献类型：
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作者：
Randau, L;Schauer, S;Jahn, D
在古细菌、大多数细菌和叶绿体中卟啉生物合成的第一步中，谷氨酰-tRNA 还原酶 (GluTR) 催化谷氨酰-tRNA 依赖 NADPH 还原为谷氨酸-1-半醛。通过对大肠杆菌 Glu-tRNA(Glu) 的 51 个变异转录本进行动力学分析，确定了 tRNA(Glu) 中对大肠杆菌 GluTR 利用重要的元素。 GluTR 识别需要碱基 U8、U13*G22**A46 碱基三重、三级 Watson-Crick 碱基对 19*56 以及残基 47 的缺失。所有这些碱基都有助于形成大肠杆菌 tRNAGlu 独特的三级核心。缺乏整个反密码子茎/环但保留三级核心结构的两个 tRNA(Glu) 分子仍然是 GluTR 的底物，而进一步减小 tRNA 大小以形成微型螺旋则消除了 GluTR 活性。 RNA足迹实验揭示了GluTR与Glu-tRNA(Glu)三级核心的物理相互作用。大肠杆菌 GluTR 对错误的 Glu-tRNA (Gln) 显示出明显的选择性。我们得出的结论是，大肠杆菌 tRNA(Glu) 独特的三级核心结构足以让大肠杆菌 GluTR 特异性地区分其谷氨酰-tRNA 底物。
During the first step of porphyrin biosynthesis in Archaea, most bacteria, and in chloroplasts glutamyl-tRNA reductase (GluTR) catalyzes the NADPH-dependent reduction of glutamyl-tRNA to glutamate-1-semialdehyde. Elements in tRNA(Glu) important for utilization by Escherichia coli GluTR were determined by kinetic analysis of 51 variant transcripts of E. coli Glu-tRNA(Glu). Base U8, the U13*G22**A46 base triple, the tertiary Watson-Crick base pair 19*56, and the lack of residue 47 are required for GluTR recognition. All of these bases contribute to the formation of the unique tertiary core of E. coli tRNAGlu. Two tRNA(Glu) molecules lacking the entire anticodon stem/loop but retaining the tertiary core structure remained substrates for GluTR, while further decreasing tRNA size toward a minihelix abolished GluTR activity. RNA footprinting experiments revealed the physical interaction of GluTR with the tertiary core of Glu-tRNA(Glu). E. coli GluTR showed clear selectivity against mischarged Glu-tRNA(Gln). We concluded that the unique tertiary core structure of E. coli tRNA(Glu) was sufficient for E. coli GluTR to distinguish specifically its glutamyl-tRNA substrate.