TtcA a new tRNA-thioltransferase with an Fe-S cluster Article - 2014

Denis Bouvier, Natty Labessan, Martin Clémancey, Jean-Marc Latour, Jean-Luc Ravanat, Marc Fontecave, Mohamed Atta

Denis Bouvier, Natty Labessan, Martin Clémancey, Jean-Marc Latour, Jean-Luc Ravanat, Marc Fontecave, Mohamed Atta, « TtcA a new tRNA-thioltransferase with an Fe-S cluster  », Nucleic Acids Research, 2014, pp. 7960-7970. ISSN 0305-1048

Abstract

TtcA catalyzes the post-transcriptional thiolation of cytosine 32 in some tRNAs. The enzyme from Es-cherichia coli was homologously overexpressed in E. coli. The purified enzyme is a dimer containing an iron–sulfur cluster and displays activity in in vitro assays. The type and properties of the cluster were investigated using a combination of UV-visible absorption , EPR and M ¨ ossbauer spectroscopy, as well as by site-directed mutagenesis. These studies demonstrated that the TtcA enzyme contains a redox-active and oxygen-sensitive [4Fe-4S] cluster, chelated by only three cysteine residues and absolutely essential for activity. TtcA is unique tRNA-thiolating enzyme using an iron–sulfur cluster for catalyzing a non-redox reaction.

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