pfam04446: Thg1 (This model is not part of the current CDD release)
tRNAHis guanylyltransferase
The Thg1 protein from Saccharomyces cerevisiae is responsible for adding a GMP residue to the 5' end of tRNA His. The catalytic domain 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. Thg1 possesses an active site with three acidic residues that chelate Mg++ cations. Thg1 catalyzes polymerization similar to the 5'-3' polymerases.
Jiyao W et al.(2023). "The conserved domain database in 2023.",