v5.1.0.3
Cicer data from the Legume Information System
Type | Homologous_superfamily |
Description | tRNA His molecules are unusual in having an extra 5' GMP residue (G(-1)) that, in eukaryotes, is added after transcription and RNase P cleavage. Incorporation of this G(-1) residue is a rare example of nucleotide addition occurring at an RNA 5' end in a normal phosphodiester linkage. In Saccharomyces cerevisiae, YGR024c (Thg1p) protein is responsible for this guanylyltransferase reaction [ ]. It catalyses the guanylyltransferase step of G(-1) addition using a ppp-tRNA His substrate, and appears to catalyse the activation step using p-tRNA His and ATP. Thus, it catalyses phosphodiester bond formation at the 5' end of RNAs, formally in a 3'-5' direction []. Thg1 has also been shown to interact with the origin recognition complex and to be required for the G2/M phase transition [ ], and to have polymerase activity []. The polymerase activity has been proposed to be the ancestral activity of this enzyme []. |
Short Name | tRNAHis_GuaTrfase_Thg1_sf |