Biochemical characterization of the biosynthesis machineries of t6A, a universal modified nucleoside
type: Dataset
description: Transfer RNA are central elements of the translational system and carry a large diversity of modified nucleosides (derived from canonical nucleosides A, U, G, and C), which tune the stability, the decoding capacity and the identity of these oligonucleotides. t6A (threonylcarbamoyl-N6- adenosine) is a hypermodified nucleoside found at the position 37 (next to the anticodon) in all tRNA decoding ANN codons. It plays an essential role in the fidelity of translation through two main functions: (i) it ensures a correct conformation of the anticodon loop; (ii) it enhances codon/anticodon pairing to prevent frameshifting during translation. This nucleoside is universal, found in Archaea, Bacteria, Eukarya and also in organites such as mitochondria, which suggests that it appeared early in the evolution, probably before the last universal common ancestor (LUCA). Despite the importance of t6A and its distribution, its biosynthetic pathway has remained unknown for almost 40 years.Recently, genetic studies have shown that two universal proteins, Sua5/YrdC and Kae1/YgjD, are both necessary for synthesis of t6A in Saccharomyces cerevisiae and Escherichia coli. In Bacteria, the in vitro synthesis of t6A requires two other bacterial specific proteins called YeaZ and YjeE. In Archaea and Eukarya, Kae1 (the YgjD orthologue) is a part of a conserved protein complex called KEOPS (for Kinase Endopeptidase and Other Proteins of Small size), with three other proteins Bud32, Cgi121 and Pcc1, that have no bacterial homologues. Since its discovery in 2006 in yeast, this complex has been involved in several cellular processes (telomere homeostasis, genome maintenance, transcription regulation), but its real function remained unclear.Using an in vitro biochemical approach we aimed to characterize and compare the t6A biosynthesis systems from the three domains of life, using as model organisms Pyrococcus abyssi (Archaea) Saccharomyces cerevisiae (Eukarya), and Escherichia coli (Bacteria). We h…
identifier: NNT: 2013PA112093
issued: 2026-05-05T19:33:30.555063
language: fr
modified: 2026-05-05T19:33:30.555067
contact point: Organization
  fn: CCSD
keyword: archaea
keyword: archees
keyword: arnt
keyword: infoeu-reposemanticsdoctoralthesis
keyword: kae1
keyword: keops
keyword: luca
keyword: proteine-universelle
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: sua5
keyword: t6a
keyword: theses
keyword: trna
keyword: universal-protein
landing page: https://theses.hal.science/tel-00968096

Biochemical characterization of the biosynthesis machineries of t6A, a universal modified nucleoside
type: Distribution
format: HTML
issued: 2026-05-05T19:33:30.558010
modified: 2026-05-05T19:33:30.537390
access URL: https://theses.hal.science/tel-00968096

test_moissonnage_selune
type: Agent