Identification of a radical SAM enzyme involved in the synthesis of archaeosine.,Nature Chemical Biology

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Identification of a radical SAM enzyme involved in the synthesis of archaeosine.
Nature Chemical Biology ( IF 12.9 ) Pub Date : 2019-11-18 , DOI: 10.1038/s41589-019-0390-7
Takashi Yokogawa _{1,

2,

3} , Yuichiro Nomura ₁ , Akihiro Yasuda ₁ , Hiromi Ogino ₁ , Keita Hiura ₁ , Saori Nakada ₁ , Natsuhisa Oka _{1,

2} , Kaori Ando ₁ , Takuya Kawamura ₄ , Akira Hirata ₄ , Hiroyuki Hori ₄ , Satoshi Ohno ₁

Affiliation

Archaeosine (G+), 7-formamidino-7-deazaguanosine, is an archaea-specific modified nucleoside found at the 15th position of tRNAs. In Euryarchaeota, 7-cyano-7-deazaguanine (preQ0)-containing tRNA (q0N-tRNA), synthesized by archaeal tRNA-guanine transglycosylase (ArcTGT), has been believed to be converted to G+-containing tRNA (G+-tRNA) by the paralog of ArcTGT, ArcS. However, we found that several euryarchaeal ArcSs have lysine transfer activity to q0N-tRNA to form q0kN-tRNA, which has a preQ0 lysine adduct as a base. Through comparative genomics and biochemical experiments, we found that ArcS forms a robust complex with a radical S-adenosylmethionine (SAM) enzyme named RaSEA. The ArcS-RaSEA complex anaerobically converted q0N-tRNA to G+-tRNA in the presence of SAM and lysine via q0kN-tRNA. We propose that ArcS and RaSEA should be considered an archaeosine synthase α-subunit (lysine transferase) and β-subunit (q0kN-tRNA lyase), respectively.

中文翻译：

鉴定参与古核苷合成的自由基 SAM 酶。

Archaeosine (G+)，7-formamidino-7-deazaguanosine，是一种古细菌特异性修饰核苷，位于 tRNA 的第 15 位。在 Euryarchaeota 中，由古菌 tRNA-鸟嘌呤转糖基酶 (ArcTGT) 合成的含 7-cyano-7-deazaguanine (preQ0) 的 tRNA (q0N-tRNA) 被认为通过以下途径转化为含 G+ 的 tRNA (G+-tRNA) ArcTGT、ArcS 的旁系同源物。然而，我们发现几种广古菌 ArcS 具有向 q0N-tRNA 的赖氨酸转移活性，以形成 q0kN-tRNA，其以 preQ0 赖氨酸加合物为碱基。通过比较基因组学和生化实验，我们发现 ArcS 与名为 RaSEA 的自由基 S-腺苷甲硫氨酸 (SAM) 酶形成了一个强大的复合物。在 SAM 和赖氨酸存在下，ArcS-RaSEA 复合物通过 q0kN-tRNA 将 q0N-tRNA 厌氧转化为 G+-tRNA。

更新日期：2019-11-18

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