purine(pyrimidine) nucleoside:purine(pyrimidine) deoxyribosyltransferase
nucleoside deoxyribosyltransferase I (purine nucleoside:purinedeoxyribosyltransferase: strictly specific for transfer betweenpurine bases)
nucleoside deoxyribosyltransferase II [purine(pyrimidine)nucleoside:purine(pyrimidine) deoxyribosyltransferase]
Identification of the active site nucleophile in nucleoside 2-deoxyribosyltransferase as glutamic acid 98.
Nucleoside 2-deoxyribosyltransferase. Pre-steady-state kinetic analysis of native enzyme and mutant enzyme with an alanyl residue replacing Glu-98.
Active site amino acids that participate in the catalytic mechanism of nucleoside 2'-deoxyribosyltransferase.
Crystal structures of nucleoside 2-deoxyribosyltransferase in native and ligand-bound forms reveal architecture of the active site.
This enzyme catalyzes the cleavage of the exchange of nucleobase from a 2'-deoxyribosylnucleoside with free purine or pyrimidine. According to the literature [4], Asp72, whose sidechain carboxylate could be protonated, may stabilize the oxocarbonium transition state of deoxyribosyl moiety. Glu98 acts as a nucleophile that will make attack on the C1' atom of the transferred deoxyribosyl group, to form a covalent enzyme-substrate complex. In the course of catalysis, Asp72 may act as a general acid, which protonates the leaving nucleobase group. In the next step, this enzyme might place the free base in the proper position to accept the deoxyribose.