The crystal structure of Trz1, the long form RNase Z from yeast

Nucleic Acids Res. 2017 Jun 2;45(10):6209-6216. doi: 10.1093/nar/gkx216.


tRNAs are synthesized as precursor RNAs that have to undergo processing steps to become functional. Yeast Trz1 is a key endoribonuclease involved in the 3΄ maturation of tRNAs in all domains of life. It is a member of the β-lactamase family of RNases, characterized by an HxHxDH sequence motif involved in coordination of catalytic Zn-ions. The RNase Z family consists of two subfamilies: the short (250-400 residues) and the long forms (about double in size). Short form RNase Z enzymes act as homodimers: one subunit embraces tRNA with a protruding arm, while the other provides the catalytic site. The long form is thought to contain two fused β-lactamase domains within a single polypeptide. Only structures of short form RNase Z enzymes are known. Here we present the 3.1 Å crystal structure of the long-form Trz1 from Saccharomyces cerevisiae. Trz1 is organized into two β-lactamase domains connected by a long linker. The N-terminal domain has lost its catalytic residues, but retains the long flexible arm that is important for tRNA binding, while it is the other way around in the C-terminal domain. Trz1 likely evolved from a duplication and fusion of the gene encoding the monomeric short form RNase Z.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Catalytic Domain
  • Conserved Sequence
  • Crystallography, X-Ray
  • Endoribonucleases / chemistry*
  • Evolution, Molecular
  • Models, Molecular
  • Open Reading Frames
  • Protein Conformation
  • Protein Domains
  • RNA, Transfer / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • RNA, Transfer
  • Endoribonucleases
  • tRNase Z, S cerevisiae