A THERMODYNAMIC STUDY OF UNUSUALLY STABLE RNA AND DNA HAIRPINS
A THERMODYNAMIC STUDY OF UNUSUALLY STABLE RNA AND DNA HAIRPINS
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DOI：
10.1093/nar/19.21.5901
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发表时间：
1991-11-11
影响因子：
14.9
通讯作者：
TINOCO, I
中科院分区：
文献类型：
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作者：
ANTAO, VP;LAI, SY;TINOCO, I
在来自不同生物体的核糖体 RNA 中鉴定出的 RNA 四环序列中，约 70% 属于 (UNCG) 或 (GNRA) 家族（其中 N = A、C、G 或 U；R = A 或 G）。具有这些环序列的RNA发夹形成异常稳定的四环结构。我们研究了 RNA 发夹 GGAC(UUCG)GUCC 和几种序列变体，以确定改变环序列和闭环碱基对对 (UNCG) 四环热力学稳定性的影响。具有保守环 G(CUUG)C 的发夹 GGAG(CUUG)CUCC 也异常稳定。我们确定了解链温度 (T(m))，并获得了 DNA 发夹的热力学参数，其序列类似于具有 (UNCG)、C(GNRA)G、C(GAUA)G 和 G(CUUG)C 环的稳定 RNA 发夹。环中具有 (TTCG)、(dUdUCG) 和相关序列的 DNA 发夹，与它们的 RNA 对应物不同，不会形成异常稳定的发夹。然而，与具有 C(TTTT)G 或 C(AAAA)G 环的发夹相比，具有共有环序列 C(GNRA)G 的 DNA 发夹非常稳定。 C(GATA)G 和 G(CTTG)C 环也非常稳定。异常稳定的 DNA 发夹的相对稳定性与在其 RNA 类似物中观察到的相对稳定性相似。
About 70% of the RNA tetra-loop sequences identified in ribosomal RNAs from different organisms fall into either (UNCG) or (GNRA) families (where N = A, C, G, or U; and R = A or G). RNA hairpins with these loop sequences form unusually stable tetra-loop structures. We have studied the RNA hairpin GGAC(UUCG)GUCC and several sequence variants to determine the effect of changing the loop sequence and the loop-closing base pair on the thermodynamic stability of (UNCG) tetra-loops. The hairpin GGAG(CUUG)CUCC with the conserved loop G(CUUG)C was also unusually stable. We have determined melting temperatures (T(m)), and obtained thermodynamic parameters for DNA hairpins with sequences analogous to stable RNA hairpins with (UNCG), C(GNRA)G, C(GAUA)G, and G(CUUG)C loops. DNA hairpins with (TTCG), (dUdUCG), and related sequences in the loop, unlike their RNA counterparts, did not form unusually stable hairpins. However, DNA hairpins with the consensus loop sequence C(GNRA)G were very stable compared to hairpins with C(TTTT)G or C(AAAA)G loops. The C(GATA)G and G(CTTG)C loops were also extra stable. The relative stabilities of the unusually stable DNA hairpins are similar to those observed for their RNA analogs.