InterPro domain: IPR024956

General Information

  • Identifier IPR024956
  • Description tRNAHis guanylyltransferase catalytic domain

Abstract

The Thg1 protein from Saccharomyces cerevisiae is responsible for adding a GMP residue to the 5' end of tRNA His [ 1 ]. The catalytic domain of Thg1 contains a RRM (ferredoxin) fold palm domain, just like the viral RNA-dependent RNA polymerases, reverse transcriptases, family A and B DNA polymerases, adenylyl cyclases, diguanylate cyclases (GGDEF domain) and the predicted polymerase of the CRISPR system [ 2 ]. Thg1 possesses an active site with three acidic residues that chelate Mg++ cations [ 3 ]. Thg1 likely catalyses polymerisation using a similar mechanism to the 5'-3' polymerases [ 3 , 3 ].


1. tRNAHis maturation: an essential yeast protein catalyzes addition of a guanine nucleotide to the 5' end of tRNAHis. Genes Dev. 17, 2889-901
2. Presence of a classical RRM-fold palm domain in Thg1-type 3'- 5'nucleic acid polymerases and the origin of the GGDEF and CRISPR polymerase domains. Biol. Direct 5, 43
3. tRNA(His) guanylyltransferase (THG1), a unique 3'-5' nucleotidyl transferase, shares unexpected structural homology with canonical 5'-3' DNA polymerases. Proc. Natl. Acad. Sci. U.S.A. 107, 20305-10

Species distribution

Gene table