Importance of the maintenance pathway in the regulation of the activity of Escherichia coli ribonucleotide reductase.

ABSTRACT: Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides in all organisms. The Escherichia coli class Ia RNR is composed of alpha and beta subunits that form an alpha 2beta 2 active complex. beta contains the diferric tyrosyl radical (Y (*)) cofactor that is essential for the reduction process that occurs on alpha. [Y (*)] in vitro is proportional to RNR activity, and its regulation in vivo potentially represents a mechanism for controlling RNR activity. To examine this thesis, N- and C-terminal StrepII-tagged beta under the control of an l-arabinose promoter were constructed. Using these constructs and with [ l-arabinose] varying from 0 to 0.5 mM in the growth medium, [beta] could be varied from 4 to 3300 microM. [Y (*)] in vivo and on affinity-purified

SUBMITTER: Hristova D 

PROVIDER: S-EPMC2801593 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature