N-terminal triphosphatase domain of mRNA capping enzyme
mRNA capping enzyme, also known as RNA guanylyltransferase and 5'-phosphatase (RNGTT) or mammalian mRNA capping enzyme (Mce1) in mammals, is a bifunctional enzyme that catalyzes the first two steps of cap formation: (1) by removing the gamma-phosphate from the 5'-triphosphate end of nascent mRNA to yield a diphosphate end using the polynucleotide 5'-phosphatase activity (EC 3.1.3.33) of the N-terminal triphosphatase domain; and (2) by transferring the GMP moiety of GTP to the 5'-diphosphate terminus through the C-terminal mRNA guanylyltransferase domain (EC 2.7.7.50). The enzyme is also referred to as CEL-1 in Caenorhabditis elegans.
Feature 1: active site [active site], 9 residue positions
Conserved feature residue pattern:C x x x x x R x x
Evidence:
Comment:the conserved histidine and asparagine in the active site loop are defining features of atypical DSPs that specialize in dephosphorylating 5'-RNA
Jiyao W et al.(2023). "The conserved domain database in 2023.",