Nonredox thiolation in tRNA occurring via sulfur activation by a [4Fe-4S] cluster.

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.
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Article dans une revue
Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2017, 114 (28), pp.7355-7360
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https://hal.archives-ouvertes.fr/hal-01631079
Contributeur : Nathalie Gon <>
Soumis le : mercredi 8 novembre 2017 - 16:25:54
Dernière modification le : lundi 4 décembre 2017 - 18:28:05

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  • HAL Id : hal-01631079, version 1

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Simon Arragain, Ornella Bimai, Pierre Legrand, Sylvain Caillat, Jean-Luc Ravanat, et al.. Nonredox thiolation in tRNA occurring via sulfur activation by a [4Fe-4S] cluster.. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2017, 114 (28), pp.7355-7360. 〈hal-01631079〉

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