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

Nucleic Acids Res. 2014 Jul;42(12):7960-70. doi: 10.1093/nar/gku508. Epub 2014 Jun 9.

Abstract

TtcA catalyzes the post-transcriptional thiolation of cytosine 32 in some tRNAs. The enzyme from Escherichia 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 Mössbauer 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Cysteine / chemistry
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / isolation & purification
  • Escherichia coli Proteins / metabolism
  • Gene Expression
  • Glutaredoxins / chemistry*
  • Glutaredoxins / genetics
  • Glutaredoxins / isolation & purification
  • Glutaredoxins / metabolism
  • Iron-Sulfur Proteins / chemistry*
  • Iron-Sulfur Proteins / genetics
  • Iron-Sulfur Proteins / isolation & purification
  • Iron-Sulfur Proteins / metabolism
  • Sulfurtransferases / chemistry*
  • Sulfurtransferases / genetics
  • Sulfurtransferases / isolation & purification
  • Sulfurtransferases / metabolism

Substances

  • Escherichia coli Proteins
  • Glutaredoxins
  • Iron-Sulfur Proteins
  • Sulfurtransferases
  • TtcA protein, E coli
  • Cysteine