Escherichia coli RNase M, is a multiply altered form of RNase I

P. R. Subbarayan, M. P. Deutscher

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


RNase M, an enzyme previously purified to homogeneity from Escherichia coli, was suggested to be the RNase responsible for mRNA degradation in this bacterium. Although related to the endoribonuclease, RNase I, its distinct properties led to the conclusion that RNase M was a second, low molecular mass, broad specificity endoribonuclease present in E. coli. However, based on sequence analysis, southern hybridization, and enzyme activity, we show that RNase M is, in fact, a multiply altered form of RNase I. In addition to three amino acid substitutions that confer the properties of RNase M on the mutated RNase I, the protein is synthesized from an rna gene that contains a UGA nonsense codon at position 5, apparently as a result of a low level of readthrough. We also suggest that RNase M is just one of several previously described endoribonuclease activities that are actually manifestations of RNase I.

Original languageEnglish (US)
Pages (from-to)1702-1707
Number of pages6
Issue number12
StatePublished - Dec 1 2001


  • Endoribonuclease
  • RNA degradation

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology


Dive into the research topics of 'Escherichia coli RNase M, is a multiply altered form of RNase I'. Together they form a unique fingerprint.

Cite this