Structural basis for sulfur relay to RNA mediated by heterohexameric TusBCD complex

Tomoyuki Numata, Shuya Fukai, Yoshiho Ikeuchi, Tsutomu Suzuki, Osamu Nureki

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


Uridine at wobble position 34 of tRNALys, tRNAGlu, and tRNAGln is exclusively modified into 2-thiouridine (s 2U), which is crucial for both precise codon recognition and recognition by the cognate aminoacyl-tRNA synthetases. Recent Escherichia coli genetic studies revealed that the products of five novel genes, tusABCDE, function in the s2U modification. Here, we solved the 2.15 Å crystal structure of the E. coli TusBCD complex, a sulfur transfer mediator, forming a heterohexamer composed of a dimer of the heterotrimer. Structure-based sequence alignment suggested two putative active site Cys residues, Cys79 (in TusC) and Cys78 (in TusD), which are exposed on the hexameric complex. In vivo mutant analyses revealed that only Cys78, in the TusD subunit, participates in sulfur transfer during the s2U modification process. Since the single Cys acts as a catalytic residue, we proposed that TusBCD mediates sulfur relay via a putative persulfide state of the TusD subunit.

Original languageEnglish
Pages (from-to)357-366
Number of pages10
Issue number2
Publication statusPublished - Feb 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Molecular Biology


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