Download MendeleyNonredox thiolation in tRNA occurring via sulfur activation by a [4Fe-4S] cluster.
Arragain, S., Bimai, O., Legrand, P., Caillat, S., Ravanat, J.L., Touati, N., Binet, L., Atta, M., Fontecave, M., Golinelli-Pimpaneau, B.(2017) Proc Natl Acad Sci U S A 114: 7355-7360
- PubMed: 28655838
- DOI: https://doi.org/10.1073/pnas.1700902114
- Primary Citation of Related Structures:
5MKO, 5MKP, 5MKQ - PubMed Abstract:
Sulfur is present in several nucleosides within tRNAs. In particular, thiolation of the universally conserved methyl-uridine at position 54 stabilizes tRNAs from thermophilic bacteria and hyperthermophilic archaea and is required for growth at high temperature. The simple nonredox substitution of the C2-uridine carbonyl oxygen by sulfur is catalyzed by tRNA thiouridine synthetases called TtuA. Spectroscopic, enzymatic, and structural studies indicate that TtuA carries a catalytically essential [4Fe-4S] cluster and requires ATP for activity. A series of crystal structures shows that ( i ) the cluster is ligated by only three cysteines that are fully conserved, allowing the fourth unique iron to bind a small ligand, such as exogenous sulfide, and ( ii ) the ATP binding site, localized thanks to a protein-bound AMP molecule, a reaction product, is adjacent to the cluster. A mechanism for tRNA sulfuration is suggested, in which the unique iron of the catalytic cluster serves to bind exogenous sulfide, thus acting as a sulfur carrier.
Organizational Affiliation:
Laboratoire de Chimie des Processus Biologiques, Unité Mixte de Recherche 8229 CNRS, Collège de France, Université Pierre et Marie Curie, 75231 Paris cedex 05, France.
