Molecular basis for the bifunctional Uba4-Urm1 sulfur-relay system in tRNA thiolation and ubiquitin-like conjugation.

Autor: Pabis M; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland., Termathe M; Max Planck Institute for Molecular Biomedicine, Muenster, Germany., Ravichandran KE; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.; Postgraduate School of Molecular Medicine, Warsaw, Poland., Kienast SD; Max Planck Institute for Molecular Biomedicine, Muenster, Germany.; Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland., Krutyhołowa R; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland., Sokołowski M; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.; Postgraduate School of Molecular Medicine, Warsaw, Poland., Jankowska U; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland., Grudnik P; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland., Leidel SA; Max Planck Institute for Molecular Biomedicine, Muenster, Germany.; Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland., Glatt S; Malopolska Centre of Biotechnology (MCB), Jagiellonian University, Krakow, Poland.
Jazyk: angličtina
Zdroj: The EMBO journal [EMBO J] 2020 Oct 01; Vol. 39 (19), pp. e105087. Date of Electronic Publication: 2020 Sep 09.
DOI: 10.15252/embj.2020105087
Abstrakt: The chemical modification of tRNA bases by sulfur is crucial to tune translation and to optimize protein synthesis. In eukaryotes, the ubiquitin-related modifier 1 (Urm1) pathway is responsible for the synthesis of 2-thiolated wobble uridine (U 34 ). During the key step of the modification cascade, the E1-like activating enzyme ubiquitin-like protein activator 4 (Uba4) first adenylates and thiocarboxylates the C-terminus of its substrate Urm1. Subsequently, activated thiocarboxylated Urm1 (Urm1-COSH) can serve as a sulfur donor for specific tRNA thiolases or participate in ubiquitin-like conjugation reactions. Structural and mechanistic details of Uba4 and Urm1 have remained elusive but are key to understand the evolutionary branch point between ubiquitin-like proteins (UBL) and sulfur-relay systems. Here, we report the crystal structures of full-length Uba4 and its heterodimeric complex with its substrate Urm1. We show how the two domains of Uba4 orchestrate recognition, binding, and thiocarboxylation of the C-terminus of Urm1. Finally, we uncover how the catalytic domains of Uba4 communicate efficiently during the reaction cycle and identify a mechanism that enables Uba4 to protect itself against self-conjugation with its own product, namely activated Urm1-COSH.
(© 2020 The Authors. Published under the terms of the CC BY 4.0 license.)
Databáze: MEDLINE
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