Tworowska Izabela, Nikonowicz Edward P
Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, USA.
J Am Chem Soc. 2006 Dec 13;128(49):15570-1. doi: 10.1021/ja0659368.
The base-base hydrogen bond interactions of the psi32,psi39-modified anticodon arm of Escherichia coli tRNAPhe have been investigated using heteronuclear NMR spectroscopy. psi32 and psi39 were enzymatically introduced into a [13C,15N]-isotopically enriched RNA sequence corresponding to the tRNAPhe anticodon arm. Both the psi32-A38 and A31-psi39 nucleotide pairs form Watson-Crick base pairing schemes and the anticodon nucleotides adopt a triloop conformation. Similar effects were observed previously with D2-isopentenyl modification of the A37 N6 that also is native to the tRNAPhe anticodon arm. These results demonstrate that the individual modifications are not sufficient to produce the 32-38 bifurcated hydrogen bond or the U-turn motifs that are observed in crystal structures of tRNAs and tRNA-protein complexes. Thus the formation of these conserved structural features in solution likely require the synergistic interaction of multiple modifications.
利用异核核磁共振光谱研究了大肠杆菌苯丙氨酸转运核糖核酸（tRNAPhe）中经ψ32、ψ39修饰的反密码子臂的碱基-碱基氢键相互作用。通过酶法将ψ32和ψ39引入到与tRNAPhe反密码子臂对应的[13C,15N]同位素富集RNA序列中。ψ32-A38和A31-ψ39核苷酸对均形成沃森-克里克碱基配对模式，且反密码子核苷酸呈现三叶草环构象。先前在tRNAPhe反密码子臂天然存在的A37 N6的D2-异戊烯基修饰中也观察到了类似效应。这些结果表明，单独的修饰不足以产生在转运核糖核酸（tRNA）和tRNA-蛋白质复合物晶体结构中观察到的32-38分叉氢键或U型基序。因此，溶液中这些保守结构特征的形成可能需要多种修饰的协同相互作用。
