AI Summary
The article discusses the discovery of an enzyme called ArcS that acts on nucleosides and tRNA modifications. This enzyme transfers lysine to a preQ0 base in tRNA, producing an intermediate called preQ0-Lys. This finding sheds light on the synthesis pathway of archaeosine, a modified nucleoside found in archaea tRNAs. The research was conducted by a team at Ehime University in collaboration with other institutions.
The genetic information on DNA is transcribed into messenger RNA (mRNA) and translated to the amino acid sequence by transfer RNA (tRNA) on the ribosome. Modified nucleosides within RNA are involved in maintaining and regulating the protein synthesis system.
Archaeosine is a modified nucleoside found only in the tRNAs from archaea, the so-called third domain of life, and contributes to the maintenance of the L-shaped tRNA three-dimensional structure.
The synthesis of archaeosine involves multiple steps, with the first step introducing a preQ0 base into tRNA via ArcTGT. In the second step, ArcS transfers an amino acid, lysine, to the preQ0 base in tRNA and synthesizes preQ0-Lys as an intermediate. The resultant preQ0-Lys in tRNA is then converted into archaeosine by RaSEA, the third-step enzyme.
This synthesis pathway of archaeosine was elucidated in 2019 through a collaborative study by Ehime University and Gifu University published in Nature Chemical Biology. However, the substrate specificity of the second-step enzyme ArcS was previously unknown.
To address this issue, a research group led by Professor Hiroyuki Hori, Lecturer Dr. Ryota Yamagami, and graduate students Shu Fujita, Yuzuru Sugio, and Dr. Takuya Kawamura (currently at Thomas Jefferson University, U.S.) at the Graduate School of Science and Engineering, Ehime University, in collaboration with Professors Takashi Yokogawa and Natsuhisa Oka