The structure of an RNA ''kissing'' hairpin complex of the HIV TAR hairpin loop and its complement
The structure of an RNA ''kissing'' hairpin complex of the HIV TAR hairpin loop and its complement
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DOI：
10.1006/jmbi.1997.1021
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发表时间：
1997-05-30
影响因子：
5.6
通讯作者：
Tinoco, I
中科院分区：
文献类型：
--
作者：
Chang, KY;Tinoco, I
我们使用核磁共振（NMR）获得了HIV-2 TAR发夹环和具有互补环序列的发夹之间形成的RNA“接吻"发夹复合物的结构。接吻发夹在天然反义反应中很重要;它们的复合物是蛋白质结合的特异性靶点。该复合物具有每个环的所有六个核苷酸配对以形成三个同轴堆叠螺旋的弯曲准连续螺旋：两个茎加上环-环相互作用螺旋。从C-13和N-15标记的RNA的异源和同源NMR数据得到的实验约束导致环-环螺旋结构的平均均方根偏差为0.83（+/-0.10）A，33个收敛结构相对于平均结构。与A型RNA相比，接吻复合物的环-环螺旋是扭曲的。它的主要沟被磷酸二酯键阻断，磷酸二酯键连接每个发夹的第一个环残基与它自己的茎，它的两侧是两个带负电荷的磷酸簇。环-环螺旋在相邻碱基对之间具有交替的螺旋扭曲。螺旋连接处的碱基对过度缠绕，螺旋连接处附近的三个碱基对采用高螺旋桨扭转。所有这些变化减少了连接每个茎和环的桥接磷酸二酯弯曲穿过环-环螺旋的大沟所需的距离，并导致在小沟表面具有局部扰动的变形RNA螺旋。交替的螺旋扭曲模式，加上环-环螺旋中的其他扭曲可能对接吻发夹复合物的Rom蛋白识别很重要。(C)出版社：Academic Press Limited
We have used nuclear magnetic resonance (NMR) to obtain the structure of an RNA ''kissing'' hairpin complex formed between the HIV-2 TAR hairpin loop and a hairpin with a complementary loop sequence. Kissing hairpins are important in natural antisense reactions; their complex is a specific target for protein binding. The complex has all six nucleotides of each loop paired to form a bent quasicontinuous helix of three coaxially stacked helices: two stems plus a loop-loop interaction helix. Experimental constraints derived from heteronuclear and homonuclear NMR data on C-13 and N-15-labeled RNA led to a structure for the loop-loop helix with an average root-mean-square deviation of 0.83 (+/-0.10) A for 33 converged structures relative to the average structure. The loop-loop helix of the kissing complex is distorted compared to A-form RNA. Its major groove is blocked by the phosphodiester bonds that connect the first loop residue of each hairpin with its own stem, and it is flanked two negatively charged phosphate clusters. The loop-loop helix has alternating helical twists between adjacent base-pairs. The base-pairs at the helix junctions are overwound and three base-pairs near the helix junctions adopt high propeller twists. All these changes reduce the distance needed for the bridging phosphodiester bends connecting each stem and loop to cross the major groove of the loop-loop helix, and result in a deformed RNA helix with localized perturbations in the minor groove surface. The alternating helical tu ist pattern, plus other distortions in the loop-loop helix may be important for Rom protein recognition of the kissing hairpin complex. (C) Academic Press Limited.