Institute of Chemistry and Biochemistry, Free University Berlin, Berlin, Germany.
Biochem Biophys Res Commun. 2011 Sep 9;412(4):532-6. doi: 10.1016/j.bbrc.2011.07.030. Epub 2011 Jul 20.
tRNAs are aminoacylated by the aminoacyl-tRNA synthetases. There are at least 20 natural amino acids, but due to the redundancy of the genetic code, 64 codons on the mRNA. Therefore, there exist tRNA isoacceptors that are aminoacylated with the same amino acid, but differ in their sequence and in the anticodon. tRNA identity elements, which are sequence or structure motifs, assure the amino acid specificity. The Seryl-tRNA synthetase is an enzyme that depends on rather few and simple identity elements in tRNA(Ser). The Seryl-tRNA-synthetase interacts with the tRNA(Ser) acceptor stem, which makes this part of the tRNA a valuable structural element for investigating motifs of the protein-RNA complex. We solved the high resolution crystal structures of two tRNA(Ser) acceptor stem microhelices and investigated their interaction with the Seryl-tRNA-synthetase by superposition experiments. The results presented here show that the amino acid side chains Ser151 and Ser156 of the synthetase are interacting in a very similar way with the RNA backbone of the microhelix and that the involved water molecules have almost identical positions within the tRNA/synthetase interface.
tRNA 由氨酰基-tRNA 合成酶氨酰化。有至少 20 种天然氨基酸，但由于遗传密码的简并性，mRNA 上有 64 个密码子。因此，存在携带相同氨基酸但在序列和反密码子上不同的 tRNA 同工受体。tRNA 身份元素是序列或结构基序，可确保氨基酸特异性。丝氨酰-tRNA 合成酶是一种依赖于 tRNA(Ser)中少数简单身份元素的酶。丝氨酰-tRNA 合成酶与 tRNA(Ser)受体茎相互作用，这使该 tRNA 部分成为研究蛋白质-RNA 复合物基序的有价值的结构元素。我们解决了两个 tRNA(Ser)受体茎微螺旋的高分辨率晶体结构，并通过叠加实验研究了它们与丝氨酰-tRNA 合成酶的相互作用。这里呈现的结果表明，合成酶的氨基酸侧链 Ser151 和 Ser156 以非常相似的方式与微螺旋的 RNA 骨架相互作用，并且涉及的水分子在 tRNA/合成酶界面内具有几乎相同的位置。
