Centre for Bacterial Cell Biology, Institute for Cell and Molecular Bioscience, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne NE2 4AX, UK.
Nat Commun. 2017 Jun 6;8:15774. doi: 10.1038/ncomms15774.
Transcription in all living organisms is accomplished by multi-subunit RNA polymerases (msRNAPs). msRNAPs are highly conserved in evolution and invariably share a ∼400 kDa five-subunit catalytic core. Here we characterize a hypothetical ∼100 kDa single-chain protein, YonO, encoded by the SPβ prophage of Bacillus subtilis. YonO shares very distant homology with msRNAPs, but no homology with single-subunit polymerases. We show that despite homology to only a few amino acids of msRNAP, and the absence of most of the conserved domains, YonO is a highly processive DNA-dependent RNA polymerase. We demonstrate that YonO is a bona fide RNAP of the SPβ bacteriophage that specifically transcribes its late genes, and thus represents a novel type of bacteriophage RNAPs. YonO and related proteins present in various bacteria and bacteriophages have diverged from msRNAPs before the Last Universal Common Ancestor, and, thus, may resemble the single-subunit ancestor of all msRNAPs.
所有生物的转录都是由多亚基 RNA 聚合酶（msRNAP）完成的。msRNAP 在进化中高度保守，始终具有一个约 400 kDa 的五亚基催化核心。在这里，我们描述了枯草芽孢杆菌 SPβ 噬菌体编码的一种假定的约 100 kDa 的单链蛋白 YonO。YonO 与 msRNAP 具有非常远的同源性，但与单亚基聚合酶没有同源性。我们表明，尽管与 msRNAP 的几个氨基酸同源，并且缺乏大多数保守结构域，但 YonO 是一种高度连续的 DNA 依赖性 RNA 聚合酶。我们证明 YonO 是 SPβ 噬菌体的一种真正的 RNA 聚合酶，它特异性地转录其晚期基因，因此代表了一种新型的噬菌体 RNA 聚合酶。在最后一个普遍共同祖先之前，各种细菌和噬菌体中存在的 YonO 和相关蛋白已经从 msRNAP 中分化出来，因此可能类似于所有 msRNAP 的单亚基祖先。
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