The interaction of RNA with TRAP: The role of triplet repeats and separating spacer nucleotides
The interaction of RNA with TRAP: The role of triplet repeats and separating spacer nucleotides
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DOI：
10.1016/j.jmb.2004.02.038
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发表时间：
2004-04-16
影响因子：
5.6
通讯作者：
Antson, AA
中科院分区：
文献类型：
--
作者：
Hopcroft, NH;Manfredo, A;Antson, AA
trp RNA 结合衰减蛋白 (TRAP) 通过与新生 trp mRNA 的前导区结合，抑制持续转录，从而调节多种芽孢杆菌中色氨酸生物合成基因的表达。 11 个亚基 TRAP 分子在与色氨酸的复合物中具有活性，并因此结合由 11 个 (G/U)AG 三联体组成的 RNA 靶片段，每个片段由两个或三个非保守“间隔”核苷酸分隔。在这里，我们报道了 TRAP 与包含由两个核苷酸分隔的 UAG 三联体的 RNA 形成的复合物以及与包含由三个核苷酸分隔的 GAG 三联体的 RNA 形成的复合物中的 TRAP 的第一个晶体结构。与 TRAP-RNA 复合物的已知结构的比较表明，三联体中用 U-1 取代 G-1 以及添加额外的间隔核苷酸都会产生更灵活的复合物。这解释了为什么在 trp 前导 RNA 中，所有三核苷酸间隔区后面都跟着一个 G-1 核苷酸。总而言之，这些结构表明 RNA 与 TRAP 的结合是通过涉及三联体的 A-2 和 G-3 核苷酸的特异性相互作用介导的。这伴随着其他核苷酸碱基之间堆积相互作用的破坏，导致驱动结合的熵增加。 (C) 2004 Elsevier Ltd. 保留所有权利。
The trp RNA-binding attenuation protein (TRAP) regulates expression of the tryptophan biosynthetic genes in several Bacilli by binding to the leader region of the nascent trp mRNA, inhibiting continued transcription. The 11 subunit TRAP molecule is active in complex with tryptophan, and binds consequently an RNA target segment consisting of 11 (G/U)AG triplets, each separated by two or three non-conserved "spacer" nucleotides. Here, we report the first crystal structures of TRAP in a complex with RNA containing UAG triplets separated by two nucleotides and in a complex with RNA containing GAG triplets separated by three nucleotides. Comparison with known structures of TRAP-RNA complexes shows that both substitution of G-1 with U-1 in the triplet and addition of an extra spacer nucleotide lead to a more flexible complex. This suggests an explanation why, in the trp leader RNA, all three-nucleotide spacer regions are followed by a G-1 nucleotide. Taken together, the structures demonstrate that RNA binding to TRAP is mediated by specific interactions involving the A-2 and G-3 nucleotides of the triplet. This is accompanied by the disruption of stacking interactions between the bases of the other nucleotides, contributing to the increase in entropy that drives binding. (C) 2004 Elsevier Ltd. All rights reserved.