Regions of bacteriophage T4 and RB69 RegA translational repressor proteins that determine RNA-binding specificity.
Regions of bacteriophage T4 and RB69 RegA translational repressor proteins that determine RNA-binding specificity.
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决定 RNA 结合特异性的噬菌体 T4 和 RB69 RegA 翻译抑制蛋白区域。
DOI：
10.1073/pnas.89.11.5053
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发表时间：
1992
影响因子：
11.1
通讯作者：
Miller,ES
中科院分区：
文献类型：
--
作者：
Jozwik,CE;Miller,ES
T4和相关噬菌体的RegA蛋白是一种高度保守的RNA结合蛋白，其抑制编码参与DNA代谢的酶的许多噬菌体mRNA的翻译。RB 69是一种与T4相关的噬菌体，具有独特的regA基因，我们已经克隆、测序并表达了该基因。预测的RB 69 RegA的氨基酸序列与T4 RegA的氨基酸序列有78%的相同性。在体内表达的质粒编码的RB 69 RegA抑制T4早期mRNA的翻译，包括rIIA、rIIB、44、45、rpbA和regA的翻译。核苷酸序列确定了几个T4和RB 69 regA突变，其相应的阻遏物的特性进行了表征。所有10个错义突变影响RB 69和T4 RegA之间保守的残基。RegA的两个区域对突变特别敏感：一个在瓦尔-15和Ala-25之间，另一个在Arg-70和Ser-73之间。序列比对和突变数据表明，从瓦尔-15到Ala-25的区域类似于DNA结合蛋白的螺旋-转角-螺旋结构域，并赋予RegA RNA结合特异性。RegA 691蛋白（Ile-24-Thr）具有体内表型，其似乎区分分级RegA介导的翻译抑制的位点特异性和合作结合模式。
RegA protein of T4 and related bacteriophages is a highly conserved RNA-binding protein that represses the translation of many phage mRNAs that encode enzymes involved in DNA metabolism. RB69, a T4-related bacteriophage, has a unique regA gene, which we have cloned, sequenced, and expressed. The predicted amino acid sequence of RB69 RegA is 78% identical to that of T4 RegA. Plasmid-encoded RB69 RegA expressed in vivo represses the translation of T4 early mRNAs, including those of rIIA, rIIB, 44, 45, rpbA, and regA. Nucleotide sequences were determined for several T4 and RB69 regA mutations, and their corresponding repressor properties were characterized. All of the 10 missense mutations affect residues conserved between RB69 and T4 RegA. Two regions of RegA are especially sensitive to mutation: one between Val-15 and Ala-25 and another between Arg-70 and Ser-73. Sequence alignments and mutational data suggest that the region from Val-15 to Ala-25 is similar to helix-turn-helix domains of DNA-binding proteins and confers RNA-binding specificity upon RegA. The RegA691 protein (Ile-24----Thr) has an in vivo phenotype that appears to distinguish site-specific and cooperative binding modes of hierarchical RegA-mediated translational repression.