Alternative model for mechanism-based inhibition of Escherichia coli ribonucleotide reductase by 2'-azido-2'-deoxyuridine 5'-diphosphate

An analysis of 2'-azido-2'-deoxynucleoside 5'-diphosphate (N3UDP)-catalyzed ribonucleotide reductase (RDPR) inactivation using 2'-(N,C)N3UDP, oxidized R1 and C225SR1 reveal that N3 release precedes N2 and N. generation. EDR analysis of 1'-,2'-,3'- or 4'-(H)N3UDP reveals no change in N. hyperfine interaction. The RDPR-(3'H)N3UDP interaction kinetics reveals that an isotopic effect causes inactivation due to N.-nucleotide intermediate tight noncovalent complex formation. A study reveals that Y. loss caused by N3UDP-RDPR interaction is slower than inactivation due to various inactivation modes.