The class Ib ribonucleotide reductase from Mycobacterium tuberculosis has two active R2F subunits

作者：Hammerstad Marta; Rohr Asmund K; Andersen Niels H; Graslund Astrid; Hogbom Martin; Andersson K Kristoffer^*

来源：Journal of Biological Inorganic Chemistry, 2014, 19(6): 893-902.

DOI：10.1007/s00775-014-1121-x

• Ribonucleotide reductase
• R2
• Tyrosyl radical
• Mycobacterium tuberculosis
• Iron

Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to their corresponding deoxyribonucleotides, playing a crucial role in DNA repair and replication in all living organisms. Class Ib RNRs require either a diiron-tyrosyl radical (Y center dot) or a dimanganese-Y center dot cofactor in their R2F subunit to initiate ribonucleotide reduction in the R1 subunit. Mycobacterium tuberculosis, the causative agent of tuberculosis, contains two genes, nrdF1 and nrdF2, encoding the small subunits R2F-1 and R2F-2, respectively, where the latter has been thought to serve as the only active small subunit in the M. tuberculosis class Ib RNR. Here, we present evidence for the presence of an active Fe (2) (III) -Y center dot cofactor in the M. tuberculosis RNR R2F-1 small subunit, supported and characterized by UV-vis, X-band electron paramagnetic resonance, and resonance Raman spectroscopy, showing features similar to those for the M. tuberculosis R2F-2-Fe (2) (III) -Y center dot cofactor. We also report enzymatic activity of Fe (2) (III) -R2F-1 when assayed with R1, and suggest that the active M. tuberculosis class Ib RNR can use two different small subunits, R2F-1 and R2F-2, with similar activity.

• 出版日期2014-8