ALTERNATIVE TERTIARY STRUCTURE ATTENUATES SELF-CLEAVAGE OF THE RIBOZYME IN THE SATELLITE RNA OF BARLEY YELLOW DWARF VIRUS
ALTERNATIVE TERTIARY STRUCTURE ATTENUATES SELF-CLEAVAGE OF THE RIBOZYME IN THE SATELLITE RNA OF BARLEY YELLOW DWARF VIRUS
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DOI：
10.1093/nar/19.19.5313
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发表时间：
1991-10-11
影响因子：
14.9
通讯作者：
SILVER, SL
中科院分区：
文献类型：
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作者：
MILLER, WA;SILVER, SL
与大麦黄矮病毒 (sBYDV) 相关的自裂解卫星 RNA 包含一个序列，预计会形成类似于“锤头”类催化 RNA 分子（核酶）的二级结构（Miller 等，1991，Virology 183, 711 - 720）。然而，这种 RNA 与其他天然存在的双髻鲨的不同之处在于其非常慢的切割速度及其结构的某些方面。一个显着的结构差异是，预计有一个额外的螺旋可能是包含三个堆叠螺旋的不寻常假结的一部分。防止额外螺旋形成并有利于锤头的核苷酸取代将自裂解率提高了 400 倍。预计恢复额外螺旋的补偿性取代会降低自裂解率，其程度与计算出的螺旋稳定性成正比。用结构敏感核酸酶对 RNA 进行部分消化，支持了野生型序列中所提出的替代结构的存在，以及快速切割突变体中锤头的形成。这种三级相互作用可以作为分子开关，控制卫星RNA的自切割速率以及可能的其他功能。
A self-cleaving satellite RNA associated with barley yellow dwarf virus (sBYDV) contains a sequence predicted to form a secondary structure similar to catalytic RNA molecules (ribozymes) of the 'hammerhead' class (Miller et al., 1991, Virology 183, 711 - 720). However, this RNA differs from other naturally occurring hammerheads both in its very slow cleavage rate, and in some aspects of its structure. One striking structural difference is that an additional helix is predicted that may be part of an unusual pseudoknot containing three stacked helices. Nucleotide substitutions that prevent formation of the additional helix and favor the hammerhead increased the self-cleavage rate up to 400-fold. Compensatory substitutions, predicted to restore the additional helix, reduced the self-cleavage rate by an extent proportional to the calculated stability of the helix. Partial digestion of the RNA with structure-sensitive nucleases supported the existence of the proposed alternative structure in the wildtype sequence, and formation of the hammerhead in the rapidly-cleaving mutants. This tertiary interaction may serve as a molecular switch that controls the rate of self-cleavage and possibly other functions of the satellite RNA.