nuc_hydro_CjNH. Nucleoside hydrolases similar to Campylobacter jejuni nucleoside hydrolase. This group contains eukaryotic and bacterial proteins similar to C. jejuni nucleoside hydrolase. Nucleoside hydrolases cleave the N-glycosidic bond in nucleosides generating ribose and the respective base. These enzymes vary in their substrate specificity. C. jejuni nucleoside hydrolase is inactive against natural nucleosides or against common nucleoside analogues.
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:This group of nucleoside hydrolases possesses a histidine or a tryptophan residue at a position equivalent to gi 21229771, loc279, the inosine-uridine-preferring nucleoside hydrolase of Crithidia fasciculata has a catalytic histidine (H241) at this position.
Jiyao W et al.(2023). "The conserved domain database in 2023.",