Novel mutator mutants of E. coli nrdAB ribonucleotide reductase: insight into allosteric regulation and control of mutation rates.

ABSTRACT: Ribonucleotide reductase (RNR) is the enzyme critically responsible for the production of the 5'-deoxynucleoside-triphosphates (dNTPs), the direct precursors for DNA synthesis. The dNTP levels are tightly controlled to permit high efficiency and fidelity of DNA synthesis. Much of this control occurs at the level of the RNR by feedback processes, but a detailed understanding of these mechanisms is still lacking. Using a genetic approach in the bacterium Escherichia coli, a paradigm for the class Ia RNRs, we isolated 23 novel RNR mutants displaying elevated mutation rates along with altered dNTP levels. The responsible amino-acid substitutions in RNR reside in three different regions: (i) the (d)ATP-binding activity domain, (ii) a novel region in the small subunit adjacent to the activity do

SUBMITTER: Ahluwalia D 

PROVIDER: S-EPMC3340444 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature