EVOLUTIONARY RELATIONSHIPS AMONG GROUP-II INTRON-ENCODED PROTEINS AND IDENTIFICATION OF A CONSERVED DOMAIN THAT MAY BE RELATED TO MATURASE FUNCTION
EVOLUTIONARY RELATIONSHIPS AMONG GROUP-II INTRON-ENCODED PROTEINS AND IDENTIFICATION OF A CONSERVED DOMAIN THAT MAY BE RELATED TO MATURASE FUNCTION
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DOI：
10.1093/nar/21.22.4991
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发表时间：
1993-11-11
影响因子：
14.9
通讯作者：
LAMBOWITZ, AM
中科院分区：
文献类型：
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作者：
MOHR, G;PERLMAN, PS;LAMBOWITZ, AM
许多 II 组内含子编码逆转录酶样蛋白，这些蛋白可能在内含子移动性和 RNA 剪接中发挥作用。我们比较了 34 个内含子编码的开放阅读框和 4 个未在内含子中编码的相关开放阅读框。许多开放阅读框都有一个逆转录酶样结构域，后面跟着一个额外的保守结构域 X 和一个 Zn2+-指状区域。一些开放阅读框丢失了功能性逆转录酶特征的保守序列块或关键氨基酸，还有一些缺乏 Zn2+-指状区域。由叶绿体 tRNA(Lys) 基因和相关的 Epifagus virginiana matK 开放阅读框编码的开放阅读框缺乏 Zn2+-指状区域，并且仅具有逆转录酶样结构域的残余物，但保留了易于识别的结构域 X。一些发现使我们推测结构域 X 可能在逆转录和 RNA 剪接过程中在内含子 RNA 的结合中发挥作用。总体而言，我们的研究结果与以下假设一致：所有已知的 II 组内含子开放阅读框都是从祖先开放阅读框进化而来的，其中包含逆转录酶、X 和 Zn2+ 指状结构域，并且逆转录酶和 Zn2+ 指状结构域在某些情况下丢失。大多数蛋白质中 X 结构域的保留可能反映了 RNA 剪接的重要功能，该功能独立于这些蛋白质的逆转录酶活性。
Many group II introns encode reverse transcriptase-like proteins that potentially function in intron mobility and RNA splicing. We compared 34 intron-encoded open reading frames and four related open reading frames that are not encoded in introns. Many of these open reading frames have a reverse transcriptase-like domain, followed by an additional conserved domain X, and a Zn2+-finger-like region. Some open reading frames have lost conserved sequence blocks or key amino acids characteristic of functional reverse transcriptases, and some lack the Zn2+-finger-like region. The open reading frames encoded by the chloroplast tRNA(Lys) genes and the related Epifagus virginiana matK open reading frame lack a Zn2+-finger-like region and have only remnants of a reverse transcriptase-like domain, but retain a readily identifiable domain X. Several findings lead us to speculate that domain X may function in binding of the intron RNA during reverse transcription and RNA splicing. Overall, our findings are consistent with the hypothesis that all of the known group II intron open reading frames evolved from an ancestral open reading frame, which contained reverse transcriptase, X, and Zn2+-finger-like domains, and that the reverse transcriptase and Zn2+-finger-like domains were lost in some cases. The retention of domain X in most proteins may reflect an essential function in RNA splicing, which is independent of the reverse transcriptase activity of these proteins.