Coenzyme B12 controls transcription of the Streptomyces class Ia ribonucleotide reductase nrdABS operon via a riboswitch mechanism.

ABSTRACT: Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotides to deoxyribonucleotides and are essential for de novo DNA synthesis and repair. Streptomycetes contain genes coding for two RNRs. The class Ia RNR is oxygen dependent, and the class II RNR is oxygen independent and requires coenzyme B12. Either RNR is sufficient for vegetative growth. We show here that the Streptomyces coelicolor M145 nrdABS genes encoding the class Ia RNR are regulated by coenzyme B12. The 5'-untranslated region of nrdABS contains a 123-nucleotide B12 riboswitch. Similar B12 riboswitches are present in the corresponding regions of eight other S. coelicolor genes. The effect of B12 on growth and nrdABS transcription was examined in a mutant in which the nrdJ gene, encoding the class II RNR, was del

SUBMITTER: Borovok I 

PROVIDER: S-EPMC1428431 | biostudies-literature | 2006 Apr

REPOSITORIES: biostudies-literature