nuc_hydro_CeIAG: Nucleoside hydrolases similar to the inosine-adenosine-guanosine-preferring nucleoside hydrolase from Caenorhabditis elegans. Nucleoside hydrolases cleave the N-glycosidic bond in nucleosides generating ribose and the respective base. These enzymes vary in their substrate specificity. This group contains eukaryotic, bacterial and archeal proteins similar to the purine-preferring nucleoside hydrolase (IAG-NH) from C. elegans and the salivary purine nucleosidase from Aedes aegypti. C. elegans IAG-NH exhibits a high affinity for the substrate analogue p-nitrophenylriboside (p-NPR).
Comment:Most nucleoside hydrolases possess either a tryptophan or a histidine at a position equivalent to PDB H241 in the base-aspecific nucleoside hydrolase of Crithidia fasciculate (2MAS_A). This histidine has been identified as the general acid in the catalysis. In the nucleoside hydrolase of the parasite Trypanosoma vivax (1HP0_A), as an alternative to general acid catalysis, the purine base of the substrate is bound between the aromatic side chains of W83 and W260, promoting the protonation of the purine base at N-7.
Comment:11292348
Comment:This group of nucleoside hydrolases possesses residues such as cysteine, proline, tyrosine, alanine, or valine, at a position equivalent to gi 21654712, loc269, the inosine-uridine-preferring nucleoside hydrolase of Crithidia fasciculata has a catalytic histidine (H241) at this position.
Comment:Active site predicted based on similar protein.
Jiyao W et al.(2023). "The conserved domain database in 2023.",